Nasa Space Images

NASA's Galaxy Evolution Explorer in Standby Mode

2012-02-14T00:33:00.000-08:00

NASA's Galaxy Evolution Explorer, or Galex, was placed in standby mode today as engineers prepare to end mission operations, nearly nine years after the telescope's launch.

The spacecraft is scheduled to be decommissioned -- taken out of service -- later this year. The mission extensively mapped large portions of the sky with sharp ultraviolet vision, cataloguing millions of galaxies spanning 10 billion years of cosmic time.

The Galaxy Evolution Explorer launched into space from a Pegasus XL rocket in April of 2003. Since completing its prime mission in the fall of 2007, the mission was extended to continue its census of stars and galaxies.

The mission's science highlights include the discovery of a gigantic comet-like tail behind a speeding star, rings of new stars around old galaxies, and "teenager" galaxies, which help to explain how galaxies evolve. The observatory also helped confirm the existence of the mysterious substance or force known as dark energy, and even caught a black hole devouring a star.

The California Institute of Technology, Pasadena, Calif., leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA's Jet Propulsion Laboratory, also in Pasadena, manages the mission and built the science instrument. The mission was developed under NASA's Explorers Program, managed by the Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on this mission. Caltech manages JPL for NASA.

Graphics and additional information about the Galaxy Evolution Explorer are online at http://www.nasa.gov/galex/ and http://www.galex.caltech.edu/ .

NASA Rover Beginning Ninth Year of Mars Work

2012-02-08T02:28:00.001-08:00

Eight years after landing on Mars for what was planned as a three-month mission, NASA's enduring Mars Exploration Rover Opportunity is working on what essentially became a new mission five months ago.

Opportunity reached a multi-year driving destination, Endeavour Crater, in August 2011. At Endeavour's rim, it has gained access to geological deposits from an earlier period of Martian history than anything it examined during its first seven years. It also has begun an investigation of the planet's deep interior that takes advantage of staying in one place for the Martian winter.

Opportunity landed in Eagle Crater on Mars on Jan. 25, 2004, Universal Time and EST (Jan. 24, PST), three weeks after its rover twin, Spirit, landed halfway around the planet. In backyard-size Eagle Crater, Opportunity found evidence of an ancient wet environment. The mission met all its goals within the originally planned span of three months. During most of the next four years, it explored successively larger and deeper craters, adding evidence about wet and dry periods from the same era as the Eagle Crater deposits.

In mid-2008, researchers drove Opportunity out of Victoria Crater, half a mile (800 meters) in diameter, and set course for Endeavour Crater, 14 miles (22 kilometers) in diameter.

"Endeavour is a window further into Mars' past," said Mars Exploration Rover Program Manager John Callas, of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The trek took three years. In a push to finish it, Opportunity drove farther during its eighth year on Mars -- 4.8 miles (7.7 kilometers) -- than in any prior year, bringing its total driving distance to 21.4 miles (34.4 kilometers).

The "Cape York" segment of Endeavour's rim, where Opportunity has been working since August 2011, has already validated the choice of Endeavour as a long-term goal. "It's like starting a new mission, and we hit pay dirt right out of the gate," Callas said.

The first outcrop that Opportunity examined on Cape York differs from any the rover had seen previously. Its high zinc content suggests effects of water. Weeks later, at the edge of Cape York, a bright mineral vein identified as hydrated calcium sulfate provided what the mission's principal investigator, Steve Squyres of Cornell University, Ithaca, N.Y., calls "the clearest evidence for liquid water on Mars that we have found in our eight years on the planet."

Mars years last nearly twice as long as Earth years. Entering its ninth Earth year on Mars, Opportunity is also heading into its fifth Martian winter. Its solar panels have accumulated so much dust since Martian winds last cleaned them -- more than in previous winters -- the rover needs to stay on a sun-facing slope to have enough energy to keep active through the winter.

Source: http://www.jpl.nasa.gov/news/news.cfm?release=2012-022

Mars-Bound Instrument Detects Solar Burst's Effects

2012-02-05T22:55:00.001-08:00

The largest solar particle event since 2005 has been detected by the radiation- monitoring instrument aboard the Mars Science Laboratory spacecraft, on its way from Earth to Mars.

The Radiation Assessment Detector, inside the mission's Curiosity rover tucked inside the spacecraft, is measuring the radiation exposure that could affect a human astronaut on a potential Mars mission. It has measured an increase resulting from a Jan. 22 solar storm observed by other NASA spacecraft. No harmful effects to the Mars Science Laboratory have been detected from this solar event.

For more information about what effects the radiation detector has measured, visit: http://www.swri.org/9what/releases/2012/rad-solarstorm.htm .

Climate Sciences and the Climate Center of JPL

2012-01-31T01:01:00.000-08:00

Understanding the far-reaching effects of climate change and how to adapt to these effects is one of the great challenges facing society today. Underpinning this challenge is the need to strengthen our understanding of the science and improve on our ability to project the future change, particularly at the regional scale. The factors that connect the buildup of CO2 to global warming require improvements in our understanding which come use of a variety of earth observations that are both available today and planned for tomorrow.

JPL lies at the forefront of key areas of the climate sciences both in developing the critical global observations of Earth required to meet these significant challenges as well as in advancing our understanding of key climate processes on many different fronts. This talk will place many aspects of the research pursued at JPL in this larger context. The JPL-based Earth science highlighted will include:

• Basic research on understanding cryospheric changes, including the loss of ice from the world’s ice sheets and subsequent challenges in modeling this ice loss.
• The monitoring of sea level rise and the challenges in understanding the factors that produce this rise and the projections of future rise.
• The planetary energy balance, our understanding of it, how it is expected to change and where gaps exist in our understanding of the change.
• The carbon cycle – how research at JPL is leading the community in a growing understanding of the carbon cycle and strategies to manage it.
• The water cycle, its component parts including clouds, precipitation, water vapor and surface and subsurface water. New ways to fingerprint the processes that shape the water cycle and determine how it is changing will be emphasized.

One of the ways these important advances are being used is through an ongoing and focused effort to evaluate Earth system models in an attempt to place some level of ultimate confidence on their projections. An important activity led by JPL is the Earth system model evaluation effort carried out in partnership with PCMDI. Highlights of this effort, drawn from the research activities above, will be described.

Vesta Likely Cold and Dark Enough for Ice

2012-01-30T06:16:00.000-08:00

Though generally thought to be quite dry, roughly half of the giant asteroid Vesta is expected to be so cold and to receive so little sunlight that water ice could have survived there for billions of years, according to the first published models of Vesta's average global temperatures and illumination by the sun.

"Near the north and south poles, the conditions appear to be favorable for water ice to exist beneath the surface," says Timothy Stubbs of NASA's Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore County. Stubbs and Yongli Wang of the Goddard Planetary Heliophysics Institute at the University of Maryland published the models in the January 2012 issue of the journal Icarus. The models are based on information from telescopes including NASA's Hubble Space Telescope.

Vesta, the second-most massive object in the asteroid belt between Mars and Jupiter, probably does not have any significant permanently shadowed craters where water ice could stay frozen on the surface all the time, not even in the roughly 300-mile-diameter (480-kilometer-diameter) crater near the south pole, the authors note. The asteroid isn't a good candidate for permanent shadowing because it is tilted on its axis at about 27 degrees, which is even greater than Earth's tilt of roughly 23 degrees. In contrast, the moon, which does have permanently shadowed craters, is tilted at only about 1.5 degrees. As a result of its large tilt, Vesta has seasons, and every part of the surface is expected to see the sun at some point during Vesta's year.

The presence or absence of water ice on Vesta tells scientists something about the tiny world's formation and evolution, its history of bombardment by comets and other objects, and its interaction with the space environment. Because similar processes are common to many other planetary bodies, including the moon, Mercury and other asteroids, learning more about these processes has fundamental implications for our understanding of the solar system as a whole. This kind of water ice is also potentially valuable as a resource for further exploration of the solar system.

Though temperatures on Vesta fluctuate during the year, the model predicts that the average annual temperature near Vesta's north and south poles is less than roughly minus 200 degrees Fahrenheit (145 kelvins). That is the critical average temperature below which water ice is thought to be able to survive in the top 10 feet or so (few meters) of the soil, which is called regolith.

Source: http://www.jpl.nasa.gov/news/news.cfm?release=2012-024

Planck Telescope Warms up as Planned

2012-01-23T05:10:00.000-08:00

The High Frequency Instrument aboard the Planck space telescope has completed its survey of the remnant light from the Big Bang explosion that created our universe. The sensor ran out of coolant on Jan. 14, as expected, ending its ability to detect this faint energy.

"The High Frequency Instrument has reached the end of its observing life, but the Low Frequency Instrument will continue observing for another year, and analysis of data from both instruments is still in the early phase," said Charles Lawrence, the U.S. Planck project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The scientific payoff from the High Frequency Instrument's brilliantly successful operation is still to come."

NASA plays an important role in the Planck mission, which is led by the European Space Agency. In addition to helping with the analysis of the data, NASA contributed several key components to the mission itself. JPL built the state-of-the-art detectors that allowed the High Frequency Instrument to detect icy temperatures down to nearly absolute zero, the coldest temperature theoretically attainable.

Less than half a million years after the universe was created 13.7 billion years ago, the initial fireball cooled to temperatures of about 4,000 degrees Celsius (about 7,200 degrees Fahrenheit), releasing bright, visible light. As the universe has expanded, it has cooled dramatically, and its early light has faded and shifted to microwave wavelengths.

By studying patterns imprinted in that light today, scientists hope to understand the Big Bang and the very early universe, as it appeared long before galaxies and stars first formed.

Planck has been measuring these patterns by surveying the whole sky with its High Frequency Instrument and its Low Frequency Instrument. Combined, they give Planck unparalleled wavelength coverage and the ability to resolve faint details.

Launched in May 2009, the minimum requirement for success was for the spacecraft to complete two whole surveys of the sky. In the end, Planck worked perfectly in completing not two, but five whole-sky surveys with both instruments.

The Low Frequency Instrument will continue surveying the sky for a large part of 2012, providing data to improve the quality of the final results. The first results on the Big Bang and very early universe will not come for another year.

Read the full European Space Agency news release at http://www.esa.int/SPECIALS/Planck/SEMXWNMXDXG_0.html .

Spacecraft Reunite in Lunar Orbit

2012-01-19T03:25:00.000-08:00

During GRAIL's science mission, the two spacecraft will transmit radio signals precisely defining the distance between them. As they fly over areas of greater and lesser gravity caused by visible features such as mountains and craters, and masses hidden beneath the lunar surface, the distance between the two spacecraft will change slightly.

Scientists will translate this information into a high-resolution map of the moon's gravitational field. The data will allow scientists to understand what goes on below the lunar surface. This information will increase knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.

Each spacecraft carries a small camera called GRAIL MoonKAM (Moon Knowledge Acquired by Middle school students) with the sole purpose of education and public outreach. The MoonKAM program is led by Sally Ride, America's first woman in space, and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego.

GRAIL MoonKAM will engage middle schools across the country in the GRAIL mission and lunar exploration. Thousands of fifth- to eighth-grade students will select target areas on the lunar surface and send requests to the GRAIL MoonKAM Mission Operations Center in San Diego. Photos of the target areas will be sent back by the GRAIL satellites for students to study.

A student contest that began in October 2011 also will choose new names for the spacecraft. The new names are scheduled to be announced in January 2012. Ride and Maria Zuber, the mission's principal investigator at the Massachusetts Institute of Technology in Cambridge, chaired the final round of judging.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the GRAIL mission for NASA's Science Mission Directorate, Washington. The GRAIL mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver built the spacecraft. JPL is a division of the Çalifornia Institute of Technology in Pasadena.

Portraits of Moons Captured by Cassini

2011-12-19T05:19:00.000-08:00

NASA’s Cassini spacecraft successfully completed its closest-ever pass over Saturn’s moon Dione on Monday, Dec. 12, slaloming its way through the Saturn system on its way to tomorrow’s close flyby of Titan. Cassini is expected to glide about 2,200 miles (3,600 kilometers) over the Titan surface on Dec. 13.

In the selection of the raw images obtained during the Cassini Dione flyby, Dione is sometimes joined by other moons. Mimas appears just beyond the dark side of Dione in one view. In another view, Epimetheus and Pandora appear together, along with Saturn’s rings.

This Dione encounter was intended primarily for Cassini's composite infrared spectrometer and radio science subsystem. However, the imaging team did capture views of the distinctive, wispy fractures on the side of Dione that always trails in its orbit around Saturn. It also obtained images of a ridge called Janiculum Dorsa on the hemisphere of Dione that always leads in its orbit around Saturn. While other flybys produced more detailed views of the surface, the best resolved images from this flyby have scales ranging from about 1,100 feet (350 meters) to about 1,600 feet (500 meters) per pixel. Janiculum Dorsa will be imaged by Cassini at higher resolution in May 2012.

All of Cassini’s raw images can be seen at http://saturn.jpl.nasa.gov/photos/raw/ .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations team is based at the Space Science Institute in Boulder, Colo. JPL is a division of Caltech.

NASA Invites Students to Name Moon-Bound Spacecraft

2011-10-11T05:52:00.000-07:00

NASA has a class assignment for U.S. students: help the agency give the twin spacecraft headed to orbit around the moon new names.

The naming contest is open to students in kindergarten through 12th grade at schools in the United States. Entries must be submitted by teachers using an online entry form. Length of submissions can range from a short paragraph to a 500-word essay. The entry deadline is Nov. 11.

NASA's solar-powered Gravity Recovery And Interior Laboratory (GRAIL)-A and GRAIL-B spacecraft lifted off from Cape Canaveral Air Force Station, Fla. on Sept. 10 to begin a three-and-a-half-month journey to the moon. GRAIL will create a gravity map of the moon using two spacecraft that orbit at very precise distances. The mission will enable scientists to learn about the moon's internal structure and composition, and give scientists a better understanding of its origin. Accurate knowledge of the moon's gravity also could be used to help choose future landing sites.

"A NASA mission to the moon is one of the reasons why I am a scientist today," said GRAIL Principal Investigator Maria Zuber from the Massachusetts Institute of Technology in Cambridge. "My hope is that GRAIL motivates young people today towards careers in science, math and technology. Getting involved with naming our two GRAIL spacecraft could inspire their interest not only in space exploration but in the sciences, and that's a good thing."

Zuber and former astronaut Sally Ride of Sally Ride Science in San Diego will chair the final round of judging. Sally Ride Science is the lead for GRAIL's MoonKAM program, which enables students to task cameras aboard the two GRAIL spacecraft to take close-up views of the lunar surface.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., a division of the California Institute of Technology, manages the GRAIL mission. GRAIL is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver built the spacecraft.

Insider's Cassini: Dr. Larry Esposito and Cassini's Ultraviolet Imaging Spectrograph

2011-09-30T06:05:00.000-07:00

I recently enjoyed the opportunity to interview yet another Cassini principal investigator (PI) for my "Insider's Cassini" column.

I've known Dr. Larry Esposito of the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) for nearly 20 years, but this is the first chance I've had to delve into the nifty results of his Cassini instrument, the ultraviolet imaging spectrograph (UVIS).

Dr. Esposito is from Schenectady, N.Y., and unlike me can probably spell his hometown without Googling. He attended my alma mater MIT to obtain his undergraduate degree before pursuing a PhD from U-Mass Amherst. He then moved to LASP in 1977 and he's been there ever since, opining he's "never had a real job" as he climbed the ranks from research associate, lecturer, associate professor, and finally to full professor of astrophysical and planetary science.

From his early work at LASP, he became "addicted to space missions" and has never looked back, working on such diverse projects as Pioneer Venus, Mars Observer, Phobos (a Russian mission), Galileo, Voyager, Mars '96, and of course Cassini. He also has made observations with the Hubble Space Telescope and has been the principal investigator for a number of Venus mission proposals. Even though he was on the imaging team for Pioneer 11 and Venus Express, most of his career has been devoted to ultraviolet spectroscopy of the planets, a perfect fit for UVIS.

UVIS is one of four Optical Remote Sensing (ORS) instruments on Cassini, similar to the ultraviolet instruments on Pioneer Venus, Voyager, and Galileo -- but with higher spatial, spectral, and time resolution. It has a significant data volume requirement (though not as much as a visible-light camera) and can provide useful observations to aid all five Cassini science disciplines -- Titan, icy moons, rings, magnetosphere, and Saturn itself.

Dr. Esposito told me UVIS is on nearly all the time, with his goal of UVIS "never being turned off" given its ability to obtain rich science data from almost every target. UVIS can take images and spectra simultaneously, basically enabling each pixel to have its own spectrum (something new on Cassini in ultraviolet wavelengths). UVIS is about the size of a small piece of carry-on luggage, with a mass of 15 kilograms and a peak power usage of only 14 watts. Speaking of carry-on luggage, I must share the anecdote of UVIS' trip to JPL from Colorado. The instrument initially went to JPL in checked baggage, but the case arrived dented. After that, it enjoyed a one-way journey to LAX in its own economy seat (next to a LASP engineer), where that ticket was charged to a "Mr. U. V. Experiment"! Fortunately, U.V. had an uneventful flight halfway across the country.

UVIS is essentially a telescope with four apertures -- two imaging spectrometers and two point detectors. The two UVIS spectrometers are called the EUV (extreme) and FUV (far) imaging spectrometers; UVIS covers a wavelength range of 55 to 192 nanometers (recall visible light roughly spans 390-750 nanometers). As Dr. Esposito put it, UVIS has a "butterflies'-eyes view," given these insects see in ultraviolet wavelengths.

The UVIS point detectors include a hydrogen/deuterium absorption cell, which measures this critical ratio important for solar system formation models (and Lyman-alpha in the hydrogen spectrum), and a high-speed photometer which observes distant stars and our sun during occultations, up to 1,000 times per second!

NASA's WISE Mission Captures Black Hole's Wildly Flaring Jet

2011-09-27T00:55:00.000-07:00

Astronomers using NASA's Wide-field Infrared Survey Explorer (WISE) have captured rare data of a flaring black hole, revealing new details about these powerful objects and their blazing jets.

Scientists study jets to learn more about the extreme environments around black holes. Much has been learned about the material feeding black holes, called accretion disks, and the jets themselves, through studies using X-rays, gamma rays and radio waves. But key measurements of the brightest part of the jets, located at their bases, have been difficult despite decades of work. WISE is offering a new window into this missing link through its infrared observations.

"Imagine what it would be like if our sun were to undergo sudden, random bursts, becoming three times brighter in a matter of hours and then fading back again. That's the kind of fury we observed in this jet," said Poshak Gandhi, a scientist with the Japan Aerospace Exploration Agency (JAXA). He is the lead author of a new study on the results appearing in the Astrophysical Journal Letters. "With WISE's infrared vision, we were able to zoom in on the inner regions near the base of the stellar-mass black hole's jet for the first time and observe the physics of jets in action."

The black hole, called GX 339-4, had been observed previously. It lies more than 20,000 light-years away from Earth near the center of our galaxy. It has a mass at least six times greater than the sun. Like other black holes, it is an ultra-dense collection of matter, with gravity that is so great even light cannot escape. In this case, the black hole is orbited by a companion star that feeds it. Most of the material from the companion star is pulled into the black hole, but some of it is blasted away as a jet flowing at nearly the speed of light.

"To see bright flaring activity from a black hole, you need to be looking at the right place at the right time," said Peter Eisenhardt, the project scientist for WISE at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "WISE snapped sensitive infrared pictures every 11 seconds for a year, covering the whole sky, allowing it to catch this rare event."

Observing the jet's variability was possible because of images taken of the same patch of sky over time, a feature of NEOWISE, the asteroid-hunting portion of the WISE mission. WISE data enabled the team to zoom in on the very compact region around the base of the jet streaming from the black hole. The size of the region is equivalent to the width of a dime seen at the distance of our sun.

The results surprised the team, showing huge and erratic fluctuations in the jet activity on timescales ranging from 11 seconds to a few hours. The observations are like a dance of infrared colors and show that the size of the jet's base varies. Its radius is approximately 15,000 miles (24,140 kilometers), with dramatic changes by as large as a factor of 10 or more.

"If you think of the black hole's jet as a firehose, then it's as if we've discovered the flow is intermittent and the hose itself is varying wildly in size," Poshak said.

The new data also allowed astronomers to make the best measurements yet of the black hole's magnetic field, which is 30,000 times more powerful than the one generated by Earth at its surface. Such a strong field is required for accelerating and channeling the flow of matter into a narrow jet. The WISE data are bringing astronomers closer than ever to understanding how this exotic phenomenon works.

GRAIL and Jobs

2011-09-20T01:49:00.000-07:00

If there's any doubt that the Space Coast will continue to be open for business, that thought was drowned out by the roar of the latest NASA launch from Florida.

NASA’s GRAIL spacecraft, the second major mission to launch from Florida since the final space shuttle flight in July, is on its way to the moon – and it carries the hopes and dreams of a nation with it.

On August 5, NASA launched Juno from Florida on its five-year journey to Jupiter. In November, we will launch the Mars Science Laboratory (MSL), Curiosity, a rover that will help us evaluate the likelihood that life has ever existed on Mars and serve as a precursor to a future human mission to the Red Planet. The vast amount of information that GRAIL sends us will be mined by scientists and students for decades to come. With these and many other exciting upcoming missions, it's clear that NASA is taking its next big leap into deep space exploration, and the space industry continues to provide the jobs and workers needed to support this critical effort.

GRAIL and MSL created good-paying American jobs. More than 3000 people nationwide were employed just on these two missions alone, from spacecraft design and processing through ground operations and ongoing mission management after the spacecraft reach their destinations.

As President Obama looks for ways to put America back to work, NASA continues to be an engine of job growth and economic opportunity. The President has repeatedly stressed that the only way for America to win the future is to out innovate, out educate, and out build our global competitors. Those three goals have been central to NASA's mission from the beginning. We continue to stretch the boundaries of science and the possible. Our partnerships to educate the next generation of scientists and engineers -- to support the jobs of tomorrow -- are growing. And our collaborations with private industry are enhancing our ability to design and build the most technologically advanced spacecraft in the world to explore new destinations and take humans farther into space.

Source:

NASA's Dawn Collects a Bounty of Beauty From Vesta

2011-09-19T05:27:00.000-07:00

A new video from NASA's Dawn spacecraft takes us on a flyover journey above the surface of the giant asteroid Vesta.

The data obtained by Dawn's framing camera, used to produce the visualizations, will help scientists determine the processes that formed Vesta's striking features. It will also help Dawn mission fans all over the world visualize this mysterious world, which is the second most massive object in the main asteroid belt.

The video, which shows Vesta as seen from Dawn's perspective, can be viewed at: http://www.jpl.nasa.gov/video/index.cfm?id=1020 .

You'll notice in the video that Vesta is not entirely lit up. There is no light in the high northern latitudes because, like Earth, Vesta has seasons. Currently it is northern winter on Vesta, and the northern polar region is in perpetual darkness. When we view Vesta's rotation from above the south pole, half is in darkness simply because half of Vesta is in daylight and half is in the darkness of night .

Another distinct feature seen in the video is a massive circular structure in the south pole region. Scientists were particularly eager to see this area close-up, since NASA's Hubble Space Telescope first detected it years ago. The circular structure, or depression, is several hundreds of miles, or kilometers, wide, with cliffs that are also several miles high. One impressive mountain in the center of the depression rises approximately 9 miles (15 kilometers) above the base of this depression, making it one of the highest elevations on all known bodies with solid surfaces in the solar system.

The collection of images, obtained when Dawn was about 1,700 miles (2,700 kilometers) above Vesta's surface, was used to determine its rotational axis and a system of latitude and longitude coordinates. One of the first tasks tackled by the Dawn science team was to determine the precise orientation of Vesta's rotation axis relative to the celestial sphere.

The zero-longitude, or prime meridian, of Vesta was defined by the science team using a tiny crater about 1,640 feet (500 meters) in diameter, which they named "Claudia," after a Roman woman during the second century B.C. Dawn's craters will be named after the vestal virgins—the priestesses of the goddess Vesta, and famous Roman women, while other features will be named for festivals and towns of that era.

The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Other scientific partners include Planetary Science Institute, Tucson, Ariz.; Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany; DLR Institute for Planetary Research, Berlin, Germany; Italian National Institute for Astrophysics, Rome; and the Italian Space Agency, Rome. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft.

Cassini Presents Saturn Moon Quintet

2011-09-17T01:43:00.000-07:00

With the artistry of a magazine cover shoot, NASA's Cassini spacecraft captured this portrait of five of Saturn's moons poised along the planet's rings.

From left to right are Janus, Pandora, Enceladus, Mimas and finally Rhea, bisected by the right side of the frame. The view was acquired at a distance of approximately 684,000 miles (1.1 million kilometers) from Rhea and 1.1 million miles (1.8 million kilometers) from Enceladus.

The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on July 29, 2011. Image scale is about 4 miles (7 kilometers) per pixel on Rhea and 7 miles (11 kilometers) per pixel on Enceladus.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org.

NASA to Announce Kepler Discovery at Media Briefing

2011-09-16T05:52:00.000-07:00

NASA will host a news briefing at 11 a.m. PDT (2 p.m. EDT), Thursday, Sept. 15, to announce a new discovery by the Kepler mission. The briefing will be held at NASA's Ames Research Center in Moffett Field, Calif. The event will be carried live on NASA Television and the agency's website at http://www.nasa.gov/ntv . It will also be streamed live, with a chat available, at http://www.ustream.tv/nasajpl2 .

Kepler is the first NASA mission capable of finding Earth-size planets in or near the "habitable zone," the region in a planetary system where liquid water can exist on the surface of the orbiting planet. Although additional observations will be needed over time to achieve that milestone, Kepler is detecting planets and planet candidates with a wide range of sizes and orbital distances to help us better understand our place in the galaxy.

A representative from Industrial Light & Magic (ILM), a division of Lucasfilm Ltd., will join a panel of scientists to discuss the discovery. The briefing participants are:
--Charlie Sobeck, Kepler deputy project manager, Ames Research Center
--Nick Gautier, Kepler project scientist, NASA's Jet Propulsion Laboratory, Pasadena, Calif.
--Laurance Doyle, lead author, SETI Institute, Mountain View, Calif.
--John Knoll, visual effects supervisor, ILM, San Francisco.
--Greg Laughlin, professor for Astrophysics and Planetary Science, University of California, Santa Cruz, Calif.

Kepler is a NASA Discovery mission. NASA Ames Research Center, Moffett Field, Calif., is the home organization of the science principal investigator and is responsible for the ground system development, mission operations and science data analysis. The Jet Propulsion Laboratory, Pasadena, Calif., managed the Kepler mission development. Ball Aerospace & Technologies Corp. of Boulder, Colo., was responsible for developing the Kepler flight system and supports mission operations. For more information about the Kepler mission, visit http://www.nasa.gov/kepler .

NASA GRAIL Moon Mission Launch Rescheduled

2011-09-09T04:55:00.000-07:00

The launch of a Delta II vehicle carrying NASA's Gravity Recovery and Interior Laboratory (GRAIL) was scrubbed today, Thursday, Sept. 8, due to weather. Conditions associated with upper level winds were in violation of the launch criteria.

The Delta II and GRAIL are safe and secure at this time. The launch is rescheduled for Friday, Sept. 9, from Space Launch Complex-17B at Cape Canaveral Air Force Station, Fla. There are two instantaneous launch opportunities at 5:33:25 a.m. PDT (8:33:25 a.m. EDT) and 6:12:31 a.m. PDT (9:12:31 a.m. EDT). The forecast for tomorrow (Sept. 9) shows a 40 percent chance of favorable weather conditions for the launch.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the GRAIL mission. The Massachusetts Institute of Technology, Cambridge, is home to the mission's principal investigator, Maria Zuber.

The GRAIL mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.

More information about GRAIL is online at: http://www.nasa.gov/grail and http://grail.nasa.gov .

NASA Picks Three Proposals for Flight Demonstration

2011-08-25T02:38:00.001-07:00

NASA has selected three proposals, including one from NASA's Jet Propulsion Laboratory in Pasadena, Calif., as Technology Demonstration Missions to transform space communications, deep space navigation and in-space propulsion capabilities.

The projects will develop and fly a space solar sail, deep space atomic clock, and space-based optical communications system.

These crosscutting flight demonstrations were selected because of their potential to provide tangible, near-term products and infuse high-impact capabilities into NASA's future space operations missions. By investing in high payoff, disruptive technology that industry does not have today, NASA matures the technology required for its future missions while proving the capabilities and lowering the cost of government and commercial space activities.

"These technology demonstration missions will improve our communications, navigation and in-space propulsion capabilities, enable future missions that could not otherwise be performed, and build the technological capability of America's space industry," said NASA Chief Technologist Bobby Braun at NASA Headquarters in Washington. "Optical communication will enable rapid return of the voluminous data associated with sending spacecraft and humans to new frontiers. High-performance atomic clocks enable a level of spacecraft navigation precision and autonomous operations in deep space never before achieved, and solar sails enable new space missions through highly efficient station-keeping or propellant-less main propulsion capabilities for spacecraft."

The proposals selected for demonstration missions are:
-- Laser Communications Relay Demonstration, David J. Israel, principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Md.
-- Deep Space Atomic Clock, Todd Ely, principal investigator at the California Institute of Technology/NASA's Jet Propulsion Laboratory in Pasadena, Calif.
-- Beyond the Plum Brook Chamber; An In-Space Demonstration of a Mission-Capable Solar Sail, Nathan Barnes, principal investigator at L'Garde Inc., of Tustin, Calif.

Technology Demonstration Missions are a vital element in NASA's space technology maturation pipeline. They prove feasibility in the environment of space and help advance innovations from concept to flight and use in missions. The advances anticipated from communications, navigation and in-space propulsion technology will allow future NASA missions to pursue bolder and more sophisticated science, enable human missions beyond low Earth orbit, and enable entirely new approaches to U.S. space operations.

The Laser Communications Relay demonstration mission will fly and validate a reliable, capable, and cost-effective optical communications technology. Optical communications technology provides data rates up to 100 times higher than today's systems, which will be needed for future human and robotic space missions. The technology is directly applicable to the next generation of NASA's space communications network. After the demonstration, the developed space and ground assets will be qualified for use by near-Earth and deep space missions requiring high bandwidth and a small ground station reception area.

The Deep Space Atomic Clock demonstration mission will fly and validate a miniaturized mercury-ion atomic clock that is 10-times more accurate than today's systems. This project will demonstrate ultra-precision timing in space and its benefits for one-way radio navigation. The investigation will fly as a hosted payload on an Iridium spacecraft and make use of GPS signals to demonstrate precision orbit determination and confirm the clock's performance. Precision timing and navigation is critical to the performance of a wide range of deep space exploration missions.

The Solar Sail demonstration mission will deploy and operate a sail area 7 times larger than ever flown in space. It is potentially applicable to a wide range of future space missions, including an advanced space weather warning system to provide more timely and accurate notice of solar flare activity. This technology also could be applied to economical orbital debris removal and propellant-less deep space exploration missions. The National Oceanic and Atmospheric Administration is collaborating with NASA and L'Garde Inc. on the demonstration.

The clock and solar sail will be ready for flight in three years. The optical communications team anticipates it will take four years to mature the technology for flight. NASA's Office of the Chief Technologist plans to make a total investment in these three missions of approximately $175 million, contingent on future appropriations. Each of the selected teams also will receive funding from partners who plan on using the technologies as part of future space missions.

Projects include all elements of the flight test demonstration including test planning, flight hardware, launch, ground operations, and post-testing assessment and reporting. Each team has proposed between one and two years of spaceflight operations and data analysis. To reduce cost, the technology demonstrations will ride to space with other payloads aboard commercially provided launch vehicles. Launches are anticipated in 2015 and 2016.

NASA Research Yields Full Map of Antarctic Ice Flow

2011-08-20T01:55:00.000-07:00

NASA-funded researchers have created the first complete map of the speed and direction of ice flow in Antarctica.

The map, which shows glaciers flowing thousands of miles from the continent's deep interior to its coast, will be critical for tracking future sea-level increases from climate change. The team created the map using integrated radar observations from a consortium of international satellites.

"This is like seeing a map of all the oceans' currents for the first time. It's a game changer for glaciology," said Eric Rignot of NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the University of California (UC), Irvine. Rignot is lead author of a paper about the ice flow published online Thursday in Science Express. "We are seeing amazing flows from the heart of the continent that had never been described before."

Rignot and UC Irvine scientists Jeremie Mouginot and Bernd Scheuchl used billions of data points captured by European, Japanese and Canadian satellites to weed out cloud cover, solar glare and land features masking the glaciers. With the aid of NASA technology, the team painstakingly pieced together the shape and velocity of glacial formations, including the previously uncharted East Antarctica, which comprises 77 percent of the continent.

Like viewers of a completed jigsaw puzzle, the scientists were surprised when they stood back and took in the full picture. They discovered a new ridge splitting the 5.4 million-square-mile (14 million-square-kilometer) landmass from east to west.

The team also found unnamed formations moving up to 800 feet (244 meters) annually across immense plains sloping toward the Antarctic Ocean and in a different manner than past models of ice migration.

"The map points out something fundamentally new: that ice moves by slipping along the ground it rests on," said Thomas Wagner, NASA's cryospheric program scientist in Washington. "That's critical knowledge for predicting future sea level rise. It means that if we lose ice at the coasts from the warming ocean, we open the tap to massive amounts of ice in the interior."

The work was conducted in conjunction with the International Polar Year (IPY) (2007-2008). Collaborators worked under the IPY Space Task Group, which included NASA; the European Space Agency (ESA); Canadian Space Agency (CSA); Japan Aerospace Exploration Agency; the Alaska Satellite Facility in Fairbanks; and MacDonald, Dettwiler and Associates of Richmond, British Columbia, Canada. The map builds on partial charts of Antarctic ice flow created by NASA, CSA and ESA using different techniques.

"To our knowledge, this is the first time that a tightly knit collaboration of civilian space agencies has worked together to create such a huge dataset of this type," said Yves Crevier of CSA. "It is a dataset of lasting scientific value in assessing the extent and rate of change in polar regions."

NASA's Juno Spacecraft Launches to Jupiter

2011-08-10T05:47:00.000-07:00

NASA's solar-powered Juno spacecraft lifted off from Cape Canaveral Air Force Station in Florida at 9:25 a.m. PDT (12:25 p.m. EDT) Friday to begin a five-year journey to Jupiter.

Juno's detailed study of the largest planet in our solar system will help reveal Jupiter's origin and evolution. As the archetype of giant gas planets, Jupiter can help scientists understand the origin of our solar system and learn more about planetary systems around other stars.

"Today, with the launch of the Juno spacecraft, NASA began a journey to yet another new frontier," NASA Administrator Charles Bolden said. "The future of exploration includes cutting-edge science like this to help us better understand our solar system and an ever-increasing array of challenging destinations."

After Juno's launch aboard an Atlas V rocket, mission controllers now await telemetry from the spacecraft indicating it has achieved its proper orientation, and that its massive solar arrays, the biggest on any NASA deep-space probe, have deployed and are generating power.

"We are on our way, and early indications show we are on our planned trajectory," said Jan Chodas, Juno project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We will know more about Juno's status in a couple hours after its radios are energized and the signal is acquired by the Deep Space Network antennas at Canberra."

Juno will cover the distance from Earth to the moon (about 250,000 miles or 402,336 kilometers) in less than one day's time. It will take another five years and 1,740 million miles (2,800 million kilometers) to complete the journey to Jupiter. The spacecraft will orbit the planet's poles 33 times and use its collection of eight science instruments to probe beneath the gas giant's obscuring cloud cover to learn more about its origins, structure, atmosphere and magnetosphere, and look for a potential solid planetary core.

With four large moons and many smaller moons, Jupiter forms its own miniature solar system. Its composition resembles that of a star, and if it had been about 80 times more massive, the planet could have become a star instead.

"Jupiter is the Rosetta Stone of our solar system," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined, and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary -- to interpret what Jupiter has to say."

Juno's name comes from Greek and Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.

The NASA Deep Space Network -- or DSN -- is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions.

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.

For more information about Juno, visit http://www.nasa.gov/juno and http://missionjuno.swri.edu .

NASA's Spitzer Finds Distant Galaxies Grazed on Gas

2011-07-12T02:26:00.000-07:00

Galaxies once thought of as voracious tigers are more like grazing cows, according to a new study using NASA's Spitzer Space Telescope.

Astronomers have discovered that galaxies in the distant, early universe continuously ingested their star-making fuel over long periods of time. This goes against previous theories that the galaxies devoured their fuel in quick bursts after run-ins with other galaxies.

"Our study shows the merging of massive galaxies was not the dominant method of galaxy growth in the distant universe," said Ranga-Ram Chary of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena, Calif. "We're finding this type of galactic cannibalism was rare. Instead, we are seeing evidence for a mechanism of galaxy growth in which a typical galaxy fed itself through a steady stream of gas, making stars at a much faster rate than previously thought."

Chary is the principal investigator of the research, appearing in the Aug. 1 issue of the Astrophysical Journal. According to his findings, these grazing galaxies fed steadily over periods of hundreds of millions of years and created an unusual amount of plump stars, up to 100 times the mass of our sun.

"This is the first time that we have identified galaxies that supersized themselves by grazing," said Hyunjin Shim, also of the Spitzer Science Center and lead author of the paper. "They have many more massive stars than our Milky Way galaxy."

Galaxies like our Milky Way are giant collections of stars, gas and dust. They grow in size by feeding off gas and converting it to new stars. A long-standing question in astronomy is: Where did distant galaxies that formed billions of years ago acquire this stellar fuel? The most favored theory was that galaxies grew by merging with other galaxies, feeding off gas stirred up in the collisions.

Chary and his team addressed this question by using Spitzer to survey more than 70 remote galaxies that existed 1 to 2 billion years after the Big Bang (our universe is approximately 13.7 billion years old). To their surprise, these galaxies were blazing with what is called H alpha, which is radiation from hydrogen gas that has been hit with ultraviolet light from stars. High levels of H alpha indicate stars are forming vigorously. Seventy percent of the surveyed galaxies show strong signs of H alpha. By contrast, only 0.1 percent of galaxies in our local universe possess this signature.

Previous studies using ultraviolet-light telescopes found about six times less star formation than Spitzer, which sees infrared light. Scientists think this may be due to large amounts of obscuring dust, through which infrared light can sneak. Spitzer opened a new window onto the galaxies by taking very long-exposure infrared images of a patch of sky called the GOODS fields, for Great Observatories Origins Deep Survey.

Further analyses showed that these galaxies furiously formed stars up to 100 times faster than the current star-formation rate of our Milky Way. What's more, the star formation took place over a long period of time, hundreds of millions of years. This tells astronomers that the galaxies did not grow due to mergers, or collisions, which happen on shorter timescales. While such smash-ups are common in the universe -- for example, our Milky Way will merge with the Andromeda galaxy in about 5 billion years -- the new study shows that large mergers were not the main cause of galaxy growth. Instead, the results show that distant, giant galaxies bulked up by feeding off a steady supply of gas that probably streamed in from filaments of dark matter.

Chary said, "If you could visit a planet in one of these galaxies, the sky would be a crazy place, with tons of bright stars, and fairly frequent supernova explosions."

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer Space Telescope mission for the agency's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech. Caltech manages JPL for NASA.

New Insights on How Solar Minimums Affect Earth

2011-06-21T05:33:00.000-07:00

Since 1611, humans have recorded the comings and goings of black spots on the sun. The number of these sunspots waxes and wanes over approximately an 11-year cycle -- more sunspots generally mean more activity and eruptions on the sun and vice versa.

The number of sunspots can change from cycle to cycle, and 2008 saw the longest and weakest solar minimum since scientists have been monitoring the sun with space-based instruments.

Observations have shown, however, that magnetic effects on Earth due to the sun, effects that cause the aurora to appear, did not go down in synch with the cycle of low magnetism on the sun. Now, a paper in Annales Geophysicae that appeared on May 16, 2011 reports that these effects on Earth did in fact reach a minimum -- indeed they attained their lowest levels of the century -- but some eight months later. The scientists believe that factors in the speed of the solar wind, and the strength and direction of the magnetic fields embedded within it, helped produce this anomalous low.

"Historically, the solar minimum is defined by sunspot number," says space weather scientist Bruce Tsurutani at NASA's Jet Propulsion Laboratory in Pasadena, Calif., who is first author on the paper. "Based on that, 2008 was identified as the period of solar minimum. But the geomagnetic effects on Earth reached their minimum quite some time later, in 2009. So we decided to look at what caused the geomagnetic minimum."

Geomagnetic effects basically amount to any magnetic changes on Earth due to the sun, and they're measured by magnetometer readings on the surface of the Earth. Such effects are usually harmless, with the only obvious sign of their presence being the appearance of auroras near the poles. However, in extreme cases, they can cause power grid failures on Earth or induce dangerous currents in long pipelines, so it is valuable to know how the geomagnetic effects vary with the sun.

Three things help determine how much energy from the sun is transferred to Earth's magnetosphere from the solar wind: the speed of the solar wind, the strength of the magnetic field outside Earth's bounds (known as the interplanetary magnetic field) and which direction it is pointing, since a large southward component is necessary to connect successfully to Earth's magnetosphere and transfer energy. The team -- which also included Walter Gonzalez and Ezequiel Echer of the Brazilian National Institute for Space Research in São José dos Campos, Brazil -- examined each component in turn.

First, the researchers noted that in 2008 and 2009, the interplanetary magnetic field was the lowest it had been in the history of the space age. This was an obvious contribution to the geomagnetic minimum. But since the geomagnetic effects didn't drop in 2008, it could not be the only factor.

To examine the speed of the solar wind, they turned to NASA's Advanced Composition Explorer (ACE), which is in interplanetary space outside the Earth's magnetosphere, approximately 1 million miles toward the sun. The ACE data showed that the speed of the solar wind stayed high during the sunspot minimum. Only later did it begin a steady decline, correlating to the timing of the decline in geomagnetic effects.

The next step was to understand what caused this decrease. The team found a culprit in something called coronal holes. Coronal holes are darker, colder areas within the sun's outer atmosphere. Fast solar wind shoots out the center of coronal holes at speeds up to 500 miles per second, but wind flowing out of the sides slows down as it expands into space.

"Usually, at solar minimum, the coronal holes are at the sun's poles," says Giuliana de Toma, a solar scientist at the National Center for Atmospheric Research whose research on this topic helped provide insight for this paper. "Therefore, Earth receives wind from only the edges of these holes, and it's not very fast. But in 2007 and 2008, the coronal holes were not confined to the poles as normal."

Those coronal holes lingered at low latitudes to the end of 2008. Consequently, the center of the holes stayed firmly pointed towards Earth, sending fast solar wind in Earth's direction. Only as they finally appeared closer to the poles in 2009 did the speed of the solar wind at Earth begin to slow down. And, of course, the geomagnetic effects and sightings of the aurora along with it.

Coronal holes seem to be responsible for minimizing the southward direction of the interplanetary magnetic field as well. The solar wind's magnetic fields oscillate on the journey from the sun to Earth. These fluctuations are known as Alfvén waves. The wind coming out of the centers of the coronal holes has large fluctuations, meaning that the southward magnetic component – like that in all the directions -- is fairly large. The wind that comes from the edges, however, has smaller fluctuations, and comparably smaller southward components. So, once again, coronal holes at lower latitudes would have a better chance of connecting with Earth's magnetosphere and causing geomagnetic effects, while mid-latitude holes would be less effective.

Working together, these three factors -- low interplanetary magnetic field strength, combined with slower solar wind speed and smaller magnetic fluctuations due to coronal hole placement -- create the perfect environment for a geomagnetic minimum.

Knowing what situations cause and suppress intense geomagnetic activity on Earth is a step toward better predicting when such events might happen. To do so well, Tsurutani points out, requires focusing on the tight connection between such effects and the complex physics of the sun. "It's important to understand all of these features better," he says. "To understand what causes low interplanetary magnetic fields and what causes coronal holes in general. This is all part of the solar cycle. And all part of what causes effects on Earth."

Voyager Set to Enter Interstellar Space

2011-06-10T01:54:00.001-07:00

More than 30 years after they left Earth, NASA's twin Voyager probes are now at the edge of the solar system. Not only that, they're still working.

And with each passing day they are beaming back a message that, to scientists, is both unsettling and thrilling.

The message is, "Expect the unexpected."

"It's uncanny," says Ed Stone of the California Institute of Technology in Pasadena, Voyager Project Scientist since 1972. "Voyager 1 and 2 have a knack for making discoveries."
Today, April 28, 2011, NASA held a live briefing to reflect on what the Voyager mission has accomplished--and to preview what lies ahead as the probes prepare to enter the realm of interstellar space in our Milky Way galaxy.

The adventure began in the late 1970s when the probes took advantage of a rare alignment of outer planets for an unprecedented Grand Tour. Voyager 1 visited Jupiter and Saturn, while Voyager 2 flew past Jupiter, Saturn, Uranus and Neptune. (Voyager 2 is still the only probe to visit Uranus and Neptune.)

When pressed to name the top discoveries from those encounters, Stone pauses, not for lack of material, but rather an embarrassment of riches. "It's so hard to choose," he says.

Stone's partial list includes the discovery of volcanoes on Jupiter's moon Io; evidence for an ocean beneath the icy surface of Europa; hints of methane rain on Saturn's moon Titan; the crazily-tipped magnetic poles of Uranus and Neptune; icy geysers on Neptune's moon Triton; planetary winds that blow faster and faster with increasing distance from the sun.

"Each of these discoveries changed the way we thought of other worlds," says Stone.

In 1980, Voyager 1 used the gravity of Saturn to fling itself slingshot-style out of the plane of the solar system. In 1989, Voyager 2 got a similar assist from Neptune. Both probes set sail into the void.

Sailing into the void sounds like a quiet time, but the discoveries have continued.

Stone sets the stage by directing our attention to the kitchen sink. "Turn on the faucet," he instructs. "Where the water hits the sink, that's the sun, and the thin sheet of water flowing radially away from that point is the solar wind. Note how the sun 'blows a bubble' around itself."

There really is such a bubble, researchers call it the "heliosphere," and it is gargantuan. Made of solar plasma and magnetic fields, the heliosphere is about three times wider than the orbit of Pluto. Every planet, asteroid, spacecraft, and life form belonging to our solar system lies inside.

The Voyagers are trying to get out, but they're not there yet. To locate them, Stone peers back into the sink: "As the water [or solar wind] expands, it gets thinner and thinner, and it can't push as hard. Abruptly, a sluggish, turbulent ring forms. That outer ring is the heliosheath--and that is where the Voyagers are now."

The heliosheath is a very strange place, filled with a magnetic froth no spacecraft has ever encountered before, echoing with low-frequency radio bursts heard only in the outer reaches of the solar system, so far from home that the sun is a mere pinprick of light.

"In many ways, the heliosheath is not like our models predicted," says Stone.

In June 2010, Voyager 1 beamed back a startling number: zero. That's the outward velocity of the solar wind where the probe is now. No one thinks the solar wind has completely stopped; it may have just turned a corner. But which way? Voyager 1 is trying to figure that out through a series of "weather vane" maneuvers, in which the spacecraft turns itself in a different direction to track the local breeze. The old spacecraft still has some moves left, it seems.

No one knows exactly how many more miles the Voyagers must travel before they "pop free" into interstellar space. Most researchers believe, however, that the end is near. "The heliosheath is 3 to 4 billion miles in thickness," estimates Stone. "That means we'll be out within five years or so."

There is plenty of power for the rest of the journey. Both Voyagers are energized by the radioactive decay of a Plutonium 238 heat source. This should keep critical subsystems running through at least 2020.

After that, he says, "Voyager will become our silent ambassador to the stars."

Each probe is famously equipped with a Golden Record, literally, a gold-coated copper phonograph record. It contains 118 photographs of Earth; 90 minutes of the world's greatest music; an audio essay entitled Sounds of Earth (featuring everything from burbling mud pots to barking dogs to a roaring Saturn 5 liftoff); greetings in 55 human languages and one whale language; the brain waves of a young woman in love; and salutations from the secretary general of the United Nations. A team led by Carl Sagan assembled the record as a message to possible extraterrestrial civilizations that might encounter the spacecraft.

"A billion years from now, when everything on Earth we've ever made has crumbled into dust, when the continents have changed beyond recognition and our species is unimaginably altered or extinct, the Voyager record will speak for us," wrote Carl Sagan and Ann Druyan in an introduction to a CD version of the record.

Some people note that the chance of aliens finding the Golden Record is fantastically remote. The Voyager probes won't come within a few light years of another star for some 40,000 years. What are the odds of making contact under such circumstances?

On the other hand, what are the odds of a race of primates evolving to sentience, developing spaceflight, and sending the sound of barking dogs into the cosmos?
Expect the unexpected, indeed.

The Voyagers were built by NASA's Jet Propulsion Laboratory in Pasadena, Calif., which continues to operate both spacecraft. JPL is a division of the California Institute of Technology in Pasadena. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate.

For more information about the Voyager spacecraft, visit: http://voyager.jpl.nasa.gov and http://www.nasa.gov/voyager .

Tweetup at NASA's JPL Previews 2011 Missions

2011-06-07T07:12:00.000-07:00

NASA's Jet Propulsion Laboratory in Pasadena, Calif., will host a Tweetup on Monday, June 6. More than 100 NASA Twitter followers, who registered in April, will attend the event.

With four NASA/JPL space missions launching in 2011 and an asteroid belt encounter nearly underway, this year will be one of the busiest ever in planetary exploration. Tweetup participants will interact with JPL scientists and engineers about these upcoming missions: Aquarius, to study ocean salinity; Grail, to study the moon's gravity field; Juno to Jupiter; and the Mars Science Laboratory/Curiosity rover. Tweetup participants also will learn about the Dawn mission and its planned encounter with the asteroid Vesta.

The Tweetup will take place from approximately 8 a.m. to 5:30 p.m. PDT. The event will be carried live on http://www.ustream.tv/nasajpl2 , and portions will also be broadcast on NASA Television from about 8:15 - 10:30 a.m. PDT and 1:30 - 3:30 p.m. PDT on June 6 at: http://www.nasa.gov/ntv.

The event will include a tour of JPL, hands-on demonstrations and a last chance to see the Curiosity rover before it ships to Florida for its launch in the fall. Tour stops will include the Spacecraft Assembly Facility, where Curiosity is undergoing assembly and testing, the mission control center of NASA's Deep Space Network, and JPL's new Earth Science Center.

Tweetup participants will mingle with fellow attendees and the staff behind @NASA, @NASAJPL, @MarsRovers, @AsteroidWatch and other NASA social media accounts.

NASA's first Tweetup was held at JPL on Jan. 21, 2009, and NASA Headquarters held its first on July 21, 2009. The most recent event was at NASA's Kennedy Space Center for the space shuttle Endeavour's final launch. Following JPL's June event, the next NASA Tweetup will be July 7-8 at Kennedy for the Space Shuttle Program's final launch. Registration for that Tweetup is open from noon EDT (9 a.m. PDT) Wednesday, June 1, through noon Thursday, June 2, at: http://www.nasa.gov/tweetup .

WEB COVERAGE
Follow the conversation before and during the June 6 event on Twitter by using the hashtag #NASATweetup and following the @NASAJPL, @JPLTweetup, and @NASATweetup accounts.

Find all the ways to connect and collaborate with NASA at: http://www.nasa.gov/connect .

Juno Solar Panels Complete Testing

2011-06-03T05:52:00.000-07:00

The three massive solar panels that will provide power for NASA's Juno spacecraft during its mission to Jupiter have seen their last photons of light until they are deployed in space after launch.

The last of the Jupiter-bound spacecraft's panels completed pre-flight testing at the Astrotech payload processing facility in Titusville, Fla., and was folded against the side of the spacecraft into its launch configuration Thursday, May 26. The solar-powered Juno spacecraft will orbit Jupiter's poles 30 times to find out more about the gas giant's origins, structure, atmosphere and magnetosphere.

"Completing the testing and stow of solar panels is always a big pre-launch milestone, and with Juno, you could say really big because our panels are really big," said Jan Chodas, Juno's project manager from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The next time these three massive solar arrays are extended to their full length, Juno will be climbing away from the Earth at about seven miles per second."

This is the first time in history a spacecraft has used solar power so far out in space (Jupiter is five times farther from the sun than Earth). To operate on the sun's light that far out requires solar panels about the size of the cargo section of a typical tractor-trailer you'd see on the interstate highway. Even with all that surface area pointed sunward, all three panels, which are 2.7 meters wide (9 feet), by 8.9 meters long (29 feet), will only generate about enough juice to power five standard light bulbs -- about 450 watts of electricity. If the arrays were optimized to operate at Earth, they would produce 12 to 14 kilowatts of power.

In other recent events, the 106-foot-long (32-meter-long), 12.5-foot-wide (3.8-meter-wide) first stage of the United Launch Alliance Atlas V launch vehicle that will carry Juno into space arrived at the Skid Strip at Cape Canaveral Air Force Station on May 24, aboard the world's second largest cargo aircraft -- a Volga-Dnepr Antonov AN-124-100. The two-stage Atlas V, along with the five solid rocket boosters that ring the first stage, will be assembled and tested on site at Launch Complex-41 at Cape Canaveral this summer.

The launch period for Juno opens Aug. 5, 2011, and extends through Aug. 26. For an Aug. 5 liftoff, the launch window opens at 8:39 a.m. PDT (11:39 am EDT) and remains open through 9:39 a.m. PDT (12:39 p.m. EDT).

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.

More information about Juno is online at http://www.nasa.gov/juno .

You can learn more about the Juno mission to Jupiter by logging on to the mission's new website. The new site was created by Juno Principal Investigator Scott Bolton in conjunction with Radical Media of New York. "It is one-stop shopping for anyone who wants to be entertained as much as informed about space science and the upcoming Juno mission," said Bolton. This Juno website can be found at: http://missionjuno.swri.edu .

A Night with the Stars...in a Conference Room

2011-06-02T03:43:00.000-07:00

Ancient astronomers looked up at the dark skies in wonder, as the stars marched by overhead like precision dancers.

In the early 17th century, Galileo Galilei brought the world one step closer to the heavens with his telescope, discovering, among other celestial marvels, moons around Jupiter, and our own moon's pockmarked surface.

Nowadays, the stars are closer to us than ever, thanks to powerful telescopes in space and on the ground. Modern astronomers don't have to step outside, because they get precise data delivered straight to their own laptops. If Galileo could see us now, he'd probably be thrilled by the advances -- and also a little puzzled that astronomy no longer means gazing through telescopes at the twinkling, dark skies.

"You can access a priceless wealth of astronomy data from your couch," said Amy Mainzer, the deputy project scientist for NASA's Wide-field Infrared Survey Explorer mission at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We can do almost all of our research on our laptops."

Sometimes astronomers do take trips out to ground-based observatories. They sleep during the day, and, instead of peering up at the night sky, they command the telescopes from computer screens. Some telescopes can also be operated remotely from laptops. Mainzer and a colleague, Mike Cushing, a member of the WISE team at JPL, recently spent an evening with the stars in a conference room at NASA's Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena.

"I guess in some sense, there is a slight loss of romance doing remote observing," said Cushing. "But it is more than made up for by being able to sleep in your own bed!"

This particular night, Mainzer and Cushing, along with an undergraduate student, Emily DeBaun from Dartmouth College in Hanover, N.H., were on a hunt for brown dwarfs. These are cool, dim stars with somewhat stunted development. They begin life like stars, but never grow massive enough to ignite nuclear fusion and shine with sunlight, as our sun does so brilliantly. Instead, brown dwarfs glow because of the heat leftover from their formation. This heat makes them easy to see with infrared telescopes.

The first brown dwarf wasn't discovered until 1995, though these objects had been predicted to exist as far back as the 1960s. More discoveries rolled in during the early 2000s with the help of data from the Sloan Digital Sky Survey and the Two Micron All-Sky Survey, an infrared all-sky mapping project sponsored by the Infrared Analysis and Processing Center and the University of Massachusetts, Amherst.

The WISE mission promises to find even more of these little stars, with its improved infrared all-sky maps. In fact, WISE will likely more than double the number of known brown dwarfs out to 25 light-years from our sun, and it may even find one that's closer to us than our closet known star, Proxima Centauri, which is about 4 light-years away. The WISE telescope wrapped up its all-sky survey and went into hibernation in Feb. 2011, but astronomers are just now beginning to sift through the data.

Mainzer and Cushing had plucked a few good brown dwarf candidates out of the WISE data. Their next step was to use the NASA Infrared Telescope Facility atop Mauna Kea in Hawaii to gather more information on the objects, and figure out if they are indeed brown dwarfs, and not something else, such as a distant galaxy masquerading as a nearby, cool star. That's what brought them to a quiet conference room late at night, when even the most owlish of the astronomers usually working in the building had gone home.

"You've got Guidedog," said Cushing, talking via speaker-phone to the NASA Infrared Telescope Facility telescope operator in Hawaii. Guidedog is the name of one of the computers that controls the camera on the telescope. The operator took control of the computer in order to focus the telescope.

Throughout the night, Mainzer and Cushing told the operator when they were ready to point the telescope at a different patch of sky, while controlling the specific settings from a software interface on their laptops. The laptop screen was projected onto a big screen in the conference room, where they could get a better view of the software.

One task involved placing their objects of interest into thin windows, or slits, which mask other nearby stars. Once the command was given to capture an image, an instrument on the Infrared Telescope Facility, called a spectrometer, broke apart the object's light into its basic components, much as a prism disperses sunlight into a rainbow. These data were then transformed into plots, called spectra, showing the various light intensities at each wavelength. The resulting peaks and dips revealed molecules making up the object, as well as its temperature.

"I think we bagged another T-dwarf," said Mainzer, referring to a classification system that organizes brown dwarfs according to their temperature. T-dwarfs are about 1,400 to 500 Kelvin (about 1,130 to 230 degrees Celsius). WISE will likely find even colder brown dwarfs, possibly even the elusive Y-dwarfs, which some theories say could be as cold as 200 Kelvin (minus 73 degrees Celsius). If such an object is revealed, it would be the coldest star-like body known.

The search for brown dwarfs continued on into night. Keeping the astronomers awake were bags of sweet-and-sour gummies and M&Ms, not to mention the thrill of discovering new worlds.

They stayed up until about 3 a.m. that night, which was midnight in Hawaii. The telescope was then handed off to another team of remote observers.

"We're still up late with the stars, even though we see them with electronic sensors instead of peering through the telescope with our own eyes," said Mainzer. "But compared to ancient astronomers, I think our sense of awe is the same, and we’re continuing the quest to understand our astonishing universe."

NASA's Spirit Rover Completes Mission on Mars

2011-05-31T01:47:00.000-07:00

NASA has ended operational planning activities for the Mars rover Spirit and transitioned the Mars Exploration Rover Project to a single-rover operation focused on Spirit's still-active twin, Opportunity.

This marks the completion of one of the most successful missions of interplanetary exploration ever launched.

Spirit last communicated on March 22, 2010, as Martian winter approached and the rover's solar-energy supply declined. The rover operated for more than six years after landing in January 2004 for what was planned as a three-month mission.

NASA checked frequently in recent months for possible reawakening of Spirit as solar energy available to the rover increased during Martian spring. A series of additional re-contact attempts ended today, designed for various possible combinations of recoverable conditions.

"Our job was to wear these rovers out exploring, to leave no unutilized capability on the surface of Mars, and for Spirit, we have done that," said Mars Exploration Rover Project Manager John Callas of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Spirit drove 4.8 miles (7.73 kilometers), more than 12 times the goal set for the mission. The drives crossed a plain to reach a distant range of hills that appeared as mere bumps on the horizon from the landing site; climbed slopes up to 30 degrees as Spirit became the first robot to summit a hill on another planet; and covered more than half a mile (nearly a kilometer) after Spirit's right-front wheel became immobile in 2006. The rover returned more than 124,000 images. It ground the surfaces off 15 rock targets and scoured 92 targets with a brush to prepare the targets for inspection with spectrometers and a microscopic imager.

"What's really important is not only how long Spirit worked or how far Spirit drove, but also how much exploration and scientific discovery Spirit accomplished," Callas said.

One major finding came, ironically, from dragging the inoperable right-front wheel as the rover was driving backwards in 2007. That wheel plowed up bright white soil. Spirit's Alpha Particle X-ray Spectrometer and Miniature Thermal Emission Spectrometer revealed that the bright material was nearly pure silica.

"Spirit's unexpected discovery of concentrated silica deposits was one of the most important findings by either rover," said Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for Spirit and Opportunity. "It showed that there were once hot springs or steam vents at the Spirit site, which could have provided favorable conditions for microbial life."

The silica-rich soil neighbors a low plateau called Home Plate, which was Spirit's main destination after the historic climb up Husband Hill. "What Spirit showed us at Home Plate was that early Mars could be a violent place, with water and hot rock interacting to make what must have been spectacular volcanic explosions. It was a dramatically different world than the cold, dry Mars of today," said Squyres.

The trove of data from Spirit could still yield future science revelations. Years of analysis of some 2005 observations by the rover's Alpha Particle X-ray Spectrometer, Miniature Thermal Emission Spectrometer and Moessbauer Spectrometer produced a report last year that an outcrop on Husband Hill bears a high concentration of carbonate. This is evidence of a wet, non-acidic ancient environment that may have been favorable for microbial life.

"What's most remarkable to me about Spirit's mission is just how extensive her accomplishments became," said Squyres. "What we initially conceived as a fairly simple geologic experiment on Mars ultimately turned into humanity's first real overland expedition across another planet. Spirit explored just as we would have, seeing a distant hill, climbing it, and showing us the vista from the summit. And she did it in a way that allowed everyone on Earth to be part of the adventure."

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rovers Opportunity and Spirit for the NASA Science Mission Directorate, Washington. For more about the rovers, see: http://www.nasa.gov/rovers and http://marsrovers.jpl.nasa.gov.

Teasing Apart Galaxy Collisions

2011-05-27T01:47:00.001-07:00

A few billion years from now, our Milky Way galaxy will collide with the Andromeda galaxy. This will mark a moment of both destruction and creation.

The galaxies will lose their separate identities as they merge into one. At the same time, cosmic clouds of gas and dust will smash together, triggering the birth of new stars.

To better understand collisions like these, astronomers have assembled an atlas of several galactic "train wrecks."

The new images combine observations from NASA's Spitzer Space Telescope, which observes infrared light, and NASA's Galaxy Evolution Explorer spacecraft, which observes ultraviolet light. By analyzing information from different parts of the light spectrum, scientists can learn much more about the collision process than from a single wavelength alone.

"We're working with the theorists to give our understanding a reality check," said the lead author of a paper on the results, Lauranne Lanz of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. "Our understanding will really be tested in a few billion years, when the Milky Way experiences its own collision."

Read the full story from the Harvard-Smithsonian Center for Astrophysics at http://www.cfa.harvard.edu/news/2011/pr201117.html

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

Caltech leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. JPL manages the mission and built the science instrument. The mission was developed under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on this mission.

More information is online at http://www.nasa.gov/galex/ and http://www.galex.caltech.edu

Cassini and Telescope See Violent Saturn Storm

2011-05-25T02:10:00.000-07:00

NASA's Cassini spacecraft and a European Southern Observatory ground-based telescope tracked the growth of a giant early-spring storm in Saturn's northern hemisphere that is so powerful it stretches around the entire planet.

The rare storm has been wreaking havoc for months and shooting plumes of gas high into the planet's atmosphere.

Cassini's radio and plasma wave science instrument first detected the large disturbance, and amateur astronomers tracked its emergence in December 2010. As it rapidly expanded, its core developed into a giant, powerful thunderstorm. The storm produced a 3,000-mile-wide (5,000-kilometer-wide) dark vortex, possibly similar to Jupiter's Great Red Spot, within the turbulent atmosphere.

The dramatic effects of the deep plumes disturbed areas high up in Saturn's usually stable stratosphere, generating regions of warm air that shone like bright "beacons" in the infrared. Details are published in this week's edition of Science Magazine.

"Nothing on Earth comes close to this powerful storm," says Leigh Fletcher, the study's lead author and a Cassini team scientist at the University of Oxford in the United Kingdom. "A storm like this is rare. This is only the sixth one to be recorded since 1876, and the last was way back in 1990."

This is the first major storm on Saturn observed by an orbiting spacecraft and studied at thermal infrared wavelengths, where Saturn's heat energy reveals atmospheric temperatures, winds and composition within the disturbance.

Temperature data were provided by the Very Large Telescope (VLT) on Cerro Paranal in Chile and Cassini's composite infrared spectrometer (CIRS), operated by NASA's Goddard Space Flight Center in Greenbelt, Md.

"Our new observations show that the storm had a major effect on the atmosphere, transporting energy and material over great distances, modifying the atmospheric winds -- creating meandering jet streams and forming giant vortices -- and disrupting Saturn's slow seasonal evolution," said Glenn Orton, a paper co-author, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

The violence of the storm -- the strongest disturbances ever detected in Saturn's stratosphere -- took researchers by surprise. What started as an ordinary disturbance deep in Saturn's atmosphere punched through the planet's serene cloud cover to roil the high layer known as the stratosphere.

"On Earth, the lower stratosphere is where commercial airplanes generally fly to avoid storms which can cause turbulence," says Brigette Hesman, a scientist at the University of Maryland in College Park who works on the CIRS team at Goddard and is the second author on the paper. "If you were flying in an airplane on Saturn, this storm would reach so high up, it would probably be impossible to avoid it."

Other indications of the storm's strength are the changes in the composition of the atmosphere brought on by the mixing of air from different layers. CIRS found evidence of such changes by looking at the amounts of acetylene and phosphine, both considered to be tracers of atmospheric motion. A separate analysis using Cassini's visual and infrared mapping spectrometer, led by Kevin Baines of JPL, confirmed the storm is very violent, dredging up larger atmospheric particles and churning up ammonia from deep in the atmosphere in volumes several times larger than previous storms. Other Cassini scientists are studying the evolving storm, and a more extensive picture will emerge soon.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The mission is managed by JPL for NASA's Science Mission Directorate in Washington. The European Southern Observatory in Garching, Germany operates the VLT in Chile. JPL is a division of the California Institute of Technology in Pasadena.

Comet Elenin: Preview of a Coming Attraction

2011-05-24T06:49:00.000-07:00

You may have heard the news: Comet Elenin is coming to the inner-solar system this fall. Comet Elenin (also known by its astronomical name C/2010 X1), was first detected on Dec. 10, 2010 by Leonid Elenin, an observer in Lyubertsy, Russia, who made the discovery "remotely" using the ISON-NM observatory near Mayhill, New Mexico.

At the time of the discovery, the comet was about 647 million kilometers (401 million miles) from Earth. Over the past four-and-a-half months, the comet has – as comets do – closed the distance to Earth's vicinity as it makes its way closer to perihelion (its closest point to the sun). As of May 4, Elenin's distance is about 274 million kilometers (170 million miles).

"That is what happens with these long-period comets that come in from way outside our planetary system," said Don Yeomans of NASA's Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "They make these long, majestic, speedy arcs through our solar system, and sometimes they put on a great show. But not Elenin. Right now that comet looks kind of wimpy."

How does a NASA scientist define cometary wimpiness?

"We're talking about how a comet looks as it safely flies past us," said Yeomans. "Some cometary visitors arriving from beyond the planetary region – like Hale-Bopp in 1997 -- have really lit up the night sky where you can see them easily with the naked eye as they safely transit the inner-solar system. But Elenin is trending toward the other end of the spectrum. You'll probably need a good pair of binoculars, clear skies, and a dark, secluded location to see it even on its brightest night."

Comet Elenin should be at its brightest shortly before the time of its closest approach to Earth on Oct. 16 of this year. At its closest point, it will be 35 million kilometers (22 million miles) from us. Can this icy interloper influence us from where it is, or where it will be in the future? What about this celestial object inspiring some shifting of the tides or even tectonic plates here on Earth? There have been some incorrect Internet speculations that external forces could cause comet Elenin to come closer.

"Comet Elenin will not encounter any dark bodies that could perturb its orbit, nor will it influence us in any way here on Earth," said Yeomans. "It will get no closer to Earth than 35 million kilometers [about 22 million miles]. "

"Comet Elenin will not only be far away, it is also on the small side for comets," said Yeomans. "And comets are not the most densely-packed objects out there. They usually have the density of something akin to loosely packed icy dirt.

"So you've got a modest-sized icy dirtball that is getting no closer than 35 million kilometers," said Yeomans. "It will have an immeasurably miniscule influence on our planet. By comparison, my subcompact automobile exerts a greater influence on the ocean's tides than comet Elenin ever will."

Yeomans did have one final thought on comet Elenin.

"This comet may not put on a great show. Just as certainly, it will not cause any disruptions here on Earth. But there is a cause to marvel," said Yeomans. "This intrepid little traveler will offer astronomers a chance to study a relatively young comet that came here from well beyond our solar system's planetary region. After a short while, it will be headed back out again, and we will not see or hear from Elenin for thousands of years. That's pretty cool."

NASA detects, tracks and characterizes asteroids and comets passing relatively close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and predicts their paths to determine if any could be potentially hazardous to our planet.

JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington, DC. JPL is a division of the California Institute of Technology in Pasadena.

Free-Floating Planets May be More Common Than Stars

2011-05-23T02:55:00.000-07:00

Astronomers, including a NASA-funded team member, have discovered a new class of Jupiter-sized planets floating alone in the dark of space, away from the light of a star. The team believes these lone worlds were probably ejected from developing planetary systems.

The discovery is based on a joint Japan-New Zealand survey that scanned the center of the Milky Way galaxy during 2006 and 2007, revealing evidence for up to 10 free-floating planets roughly the mass of Jupiter. The isolated orbs, also known as orphan planets, are difficult to spot, and had gone undetected until now. The newfound planets are located at an average approximate distance of 10,000 to 20,000 light-years from Earth.

"Although free-floating planets have been predicted, they finally have been detected, holding major implications for planetary formation and evolution models," said Mario Perez, exoplanet program scientist at NASA Headquarters in Washington.

The discovery indicates there are many more free-floating Jupiter-mass planets that can't be seen. The team estimates there are about twice as many of them as stars. In addition, these worlds are thought to be at least as common as planets that orbit stars. This would add up to hundreds of billions of lone planets in our Milky Way galaxy alone.

"Our survey is like a population census," said David Bennett, a NASA and National Science Foundation-funded co-author of the study from the University of Notre Dame in South Bend, Ind. "We sampled a portion of the galaxy, and based on these data, can estimate overall numbers in the galaxy."

The study, led by Takahiro Sumi from Osaka University in Japan, appears in the May 19 issue of the journal Nature.

The survey is not sensitive to planets smaller than Jupiter and Saturn, but theories suggest lower-mass planets like Earth should be ejected from their stars more often. As a result, they are thought to be more common than free-floating Jupiters.

Previous observations spotted a handful of free-floating, planet-like objects within star-forming clusters, with masses three times that of Jupiter. But scientists suspect the gaseous bodies form more like stars than planets. These small, dim orbs, called brown dwarfs, grow from collapsing balls of gas and dust, but lack the mass to ignite their nuclear fuel and shine with starlight. It is thought the smallest brown dwarfs are approximately the size of large planets.

On the other hand, it is likely that some planets are ejected from their early, turbulent solar systems, due to close gravitational encounters with other planets or stars. Without a star to circle, these planets would move through the galaxy as our sun and other stars do, in stable orbits around the galaxy's center. The discovery of 10 free-floating Jupiters supports the ejection scenario, though it's possible both mechanisms are at play.

"If free-floating planets formed like stars, then we would have expected to see only one or two of them in our survey instead of 10," Bennett said. "Our results suggest that planetary systems often become unstable, with planets being kicked out from their places of birth."

The observations cannot rule out the possibility that some of these planets may have very distant orbits around stars, but other research indicates Jupiter-mass planets in such distant orbits are rare.

The survey, the Microlensing Observations in Astrophysics (MOA), is named in part after a giant wingless, extinct bird family from New Zealand called the moa. A 5.9-foot (1.8-meter) telescope at Mount John University Observatory in New Zealand is used to regularly scan the copious stars at the center of our galaxy for gravitational microlensing events. These occur when something, such as a star or planet, passes in front of another, more distant star. The passing body's gravity warps the light of the background star, causing it to magnify and brighten. Heftier passing bodies, like massive stars, will warp the light of the background star to a greater extent, resulting in brightening events that can last weeks. Small planet-size bodies will cause less of a distortion, and brighten a star for only a few days or less.

A second microlensing survey group, the Optical Gravitational Lensing Experiment (OGLE), contributed to this discovery using a 4.2-foot (1.3 meter) telescope in Chile. The OGLE group also observed many of the same events, and their observations independently confirmed the analysis of the MOA group.

NASA's Jet Propulsion Laboratory, Pasadena,Calif., manages NASA's Exoplanet Exploration program office. JPL is a division of the California Institute of Technology in Pasadena.

More information about exoplanets and NASA's planet-finding program is at http://planetquest.jpl.nasa.gov.

Mars Rover Driving Leaves Distinctive Tracks

2011-05-20T03:10:00.000-07:00

When NASA's Opportunity Mars rover uses an onboard navigation capability during backward drives, it leaves a distinctive pattern in the wheel tracks visible on the Martian ground.

The pattern appears in an image posted at http://photojournal.jpl.nasa.gov/catalog/?IDNumber=PIA14129.

The rover team routinely commands Opportunity to drive backward as a precaution for extending the life of the rover's right-front wheel, which has been drawing more electrical current than the other five wheels. Rover drivers can command the rover to check for potential hazards in the drive direction, whether the rover is driving backward or forward. In that autonomous navigation mode, the rover pauses frequently, views the ground with the navigation camera on its mast, analyzes the stereo images, and makes a decision about proceeding.

When the drive is backward, the drive-direction view from the navigation camera is partially blocked by an antenna in the middle of the rover. Therefore, at each pause to check for hazards, the rover pivots slightly to the side to get a clear view. If it sees no hazard, it turns back to the direction it was going and continues the drive for about another 4 feet (1.2 meters) before checking again. This set of activities leaves tracks showing the slight turnout on a rhythmically repeated basis, like a dance step.

Opportunity has driven more than 1.6 miles (about 2.6 kilometers) since leaving "Santa Maria" crater in late March and resuming a long-term trek toward the much larger Endeavour crater. Opportunity has now driven more than 18 miles (29 kilometers) on Mars.

Opportunity and its twin rover, Spirit, completed their three-month prime missions on Mars in April 2004. Both rovers continued in years of bonus, extended missions. Both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Spirit has not communicated with Earth since March 2010.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington.

NASA's Dawn Captures First Image of Nearing Asteroid

2011-05-17T01:34:00.000-07:00

NASA's Dawn spacecraft has obtained its first image of the giant asteroid Vesta, which will help fine-tune navigation during its approach.

Dawn is expected to achieve orbit around Vesta on July 16, when the asteroid is about 188 million kilometers (117 million miles) from Earth.

The image from Dawn's framing cameras was taken on May 3 when the spacecraft began its approach and was approximately 1.21 million kilometers (752,000 miles) from Vesta. The asteroid appears as a small, bright pearl against a background of stars. Vesta is also known as a protoplanet, because it is a large body that almost formed into a planet.

"After plying the seas of space for more than a billion miles, the Dawn team finally spotted its target," said Carol Raymond, Dawn's deputy principal investigator at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This first image hints of detailed portraits to come from Dawn's upcoming visit."

Vesta is 530 kilometers (330 miles) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes obtained images of the bright orb for about two centuries, but with little surface detail.

Mission managers expect Vesta's gravity to capture Dawn in orbit on July 16. To enter orbit, Dawn must match the asteroid's path around the sun, which requires very precise knowledge of the body's location and speed. By analyzing where Vesta appears relative to stars in framing camera images, navigators will pin down its location and enable engineers to refine the spacecraft's trajectory.

Dawn will start collecting science data in early August at an altitude of approximately 1,700 miles (2,700 kilometers) above the asteroid's surface. As the spacecraft gets closer, it will snap multi-angle images, allowing scientists to produce topographic maps. Dawn will later orbit at approximately 200 kilometers (120 miles) to perform other measurements and obtain closer shots of parts of the surface. Dawn will remain in orbit around Vesta for one year. After another long cruise phase, Dawn will arrive in 2015 at its second destination, Ceres, an even more massive body in the asteroid belt.

Gathering information about these two icons of the asteroid belt will help scientists unlock the secrets of our solar system's early history. The mission will compare and contrast the two giant bodies shaped by different forces. Dawn's science instruments will measure surface composition, topography and texture. Dawn will also measure the tug of gravity from Vesta and Ceres to learn more about their internal structures. The spacecraft's full odyssey will take it on a 5-billion-kilometer (3-billion-mile) journey, which began with its launch in September 2007.

Dawn's mission to Vesta and Ceres is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala.

The University of California in Los Angeles is responsible for overall Dawn mission science. Orbital Sciences Corp. of Dulles, Va., designed and built the spacecraft. The framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research in Katlenburg-Lindau in Germany, with significant contributions by the German Aerospace Center (DLR) Institute of Planetary Research in Berlin and in coordination with the Institute of Computer and Communication Network Engineering in Braunschweig. The framing camera project is funded by NASA, the Max Planck Society and DLR.

Galileo Data Reveal Magma Ocean Under Jupiter Moon

2011-05-16T04:06:00.000-07:00

New data analysis from NASA's Galileo spacecraft reveals a subsurface ocean of molten or partially molten magma beneath the surface of Jupiter's volcanic moon Io.

The finding heralds the first direct confirmation of this kind of magma layer at Io and explains why the moon is the most volcanic object known in the solar system. The research was conducted by scientists at the University of California, Los Angeles; the University of California, Santa Cruz;, and the University of Michigan, Ann Arbor. The study is published this week in the journal Science.

"Scientists are excited we finally understand where Io's magma is coming from and have an explanation for some of the mysterious signatures we saw in some of the Galileo's magnetic field data," said Krishan Khurana, lead author of the study and former co-investigator on Galileo's magnetometer team at UCLA. "It turns out Io was continually giving off a 'sounding signal' in Jupiter's rotating magnetic field that matched what would be expected from molten or partially molten rocks deep beneath the surface."

Io produces about 100 times more lava each year than all the volcanoes on Earth. While Earth's volcanoes occur in localized hotspots like the "Ring of Fire" around the Pacific Ocean, Io's volcanoes are distributed all over its surface. A global magma ocean about 30 to 50 kilometers (20 to 30 miles) beneath Io's crust helps explain the moon's activity.

"It has been suggested that both the Earth and its moon may have had similar magma oceans billions of years ago at the time of their formation, but they have long since cooled," said Torrence Johnson, a former Galileo project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. He was not directly involved in the study. "Io's volcanism informs us how volcanoes work and provides a window in time to styles of volcanic activity that may have occurred on the Earth and moon during their earliest history."

NASA's Voyager spacecraft discovered Io's volcanoes in 1979, making that moon the only body in the solar system other than Earth known to have active magma volcanoes. The energy for the volcanic activity comes from the squeezing and stretching of the moon by Jupiter's gravity as Io orbits the largest planet in the solar system.

Galileo was launched in 1989 and began orbiting Jupiter in 1995. Unexplained signatures appeared in magnetic field data from Galileo flybys of Io in October 1999 and February 2000. After a successful mission, the spacecraft was intentionally sent into Jupiter's atmosphere in 2003.

"During the final phase of the Galileo mission, models of the interaction between Io and Jupiter's immense magnetic field, which bathes the moon in charged particles, were not yet sophisticated enough for us to understand what was going on in Io's interior," said Xianzhe Jia, a co-author of the study at the University of Michigan.

Recent work in mineral physics showed that a group of rocks known as "ultramafic" rocks become capable of carrying substantial electrical current when melted. Ultramafic rocks are igneous in origin, or form through the cooling of magma. On Earth, they are believed to originate from the mantle. The finding led Khurana and colleagues to test the hypothesis that the strange signature was produced by current flowing in a molten or partially molten layer of this kind of rock.

Tests showed that the signatures detected by Galileo were consistent with a rock such as lherzolite, an igneous rock rich in silicates of magnesium and iron found in Spitzbergen, Norway. The magma ocean layer on Io appears to be more than 50 kilometers (30 miles thick), making up at least 10 percent of the moon's mantle by volume. The blistering temperature of the magma ocean probably exceeds 1,200 degrees Celsius (2,200 degrees Fahrenheit).

The Galileo mission was managed by JPL for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.

Be Our Guest: JPL Invites Public to Open House

2011-05-11T04:59:00.000-07:00

NASA's Jet Propulsion Laboratory invites the public to its annual Open House on Saturday, May 14, and Sunday, May 15, from 9 a.m. to 5 p.m.

The event, themed "The Excitement in Explorations," invites visitors to share in the wonders of space through high-definition and 3-D videos, live demonstrations, interactions with scientists and engineers, and a first look at JPL's new Earth Science Center.

The Earth Science Center showcases our home planet and JPL's Earth science missions. Visitors will pass by two touchscreens located on opposite walls of the facility that control real-time views of "Eyes on the Earth," an interactive 3-D visualization website. Visitors will also have the opportunity to watch a movie in the 3-D theater, which seats up to 40 people.

Other Open House highlights include:

- A chance to see the most unique car in this world before it leaves Earth: The next rover bound for Mars, Mars Science Laboratory/Curiosity, in the "clean room" before it is shipped to Florida for a November 2011 launch. Curiosity also stars in its own "reality TV show" via live-streaming webcam: http://www.ustream.tv/nasajpl .
- Life-size rover models in a "Mars" test bed.
- A perennial crowd-pleaser, the Robo-Dome, where a pair of 700-pound robots glide in a high-tech arena under artificial stars. The Robo-Dome is used to simulate complex maneuvers that could be used for future space missions.
- JPL's Microdevices Lab, where engineers and scientists use tiny technology to revolutionize space exploration.
- Solar-safe telescopes that allow visitors to see the sun.

Selected locations at Open House will be featured live online, with a live chat available, on Ustream TV at: http://www.ustream.tv/nasajpl2 on Sat., May 14, from 9 a.m. to noon PDT (noon to 3 p.m. EDT).

JPL is located at 4800 Oak Grove Drive, Pasadena, Calif., 91109. Admission to Open House is free. Parking is also free, but is limited. To get to JPL, take the Berkshire Avenue/Oak Grove Drive exit from the 210 Freeway in La Canada/Flintridge. All visitors should wear comfortable shoes -- no buses will be provided from JPL parking lots. JPL will provide vans for mobility-challenged guests.

Vehicles entering NASA/JPL property are subject to inspection. Visitors cannot bring these items to NASA/JPL: weapons, explosives, incendiary devices, dangerous instruments, alcohol, illegal drugs, pets, all types of skates including skateboards, Segways and bicycles. No bags, backpacks or ice chests are allowed, except small purses and diaper bags.

More information about JPL is online at: http://www.jpl.nasa.gov . Follow us via social media, including Facebook and Twitter . A full list, with links, is at: http://www.jpl.nasa.gov/social/ .

Two NASA Sites Win Webby Awards

2011-05-06T05:15:00.000-07:00

Two NASA websites have been recognized in the 15th Annual Webby Awards -- the leading international honor for the world's best Internet sites.

NASA's main website, www.NASA.gov, received its third consecutive People's Voice Award for best government site. NASA's Global Climate Change site at http://climate.nasa.gov/, which won last year's People's Voice Award for science, won the 2011 judges' award for best science site.

"NASA is committed to sharing its compelling story with people everywhere and with every communication tool," said David Weaver, NASA's associate administrator for communications. "We are very grateful to the online community for its continued support of what we are doing, and are excited about our future."

NASA recently posted new interactive pieces on the 30th anniversary of the Space Shuttle Program and the 50th anniversary of the first U.S. spaceflight. And in the last year, the agency has streamlined its online video presentation into a single player and deployed a version of the site optimized for mobile devices.

"NASA has a very broad-based Web team that can take content, literally the best raw material in the universe, and create compelling imagery, video and multimedia pieces to tell the agency's story," said Internet Services Manager Brian Dunbar in the Office of Communications at NASA Headquarters in Washington.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Global Climate Change site for the agency's Science Mission Directorate.

"NASA satellites take key measurements of our climate, and the Global Climate Change site gives the public access to that data as a visual, immersive experience," said Randal Jackson, JPL's Internet communications manager for the Global Climate Change site. "We're grateful for the high degree of interest the public has shown in Earth's vital signs."

NASA has had a Web presence almost since HTML was invented in the early 1990's, but the site's popularity skyrocketed after a 2003 redesign and relaunch focused on making it more usable and understandable for the general public. Since then, there have been more than 1.5 billion visits to the site, and its customer-satisfaction ratings are among the highest in government and comparable to popular commercial sites.

Reaching beyond the agency's website, NASA's online communications include a Facebook page with more than 368,000 "likes"; a Twitter feed with more than a million followers; and more than 160 accounts across a variety of social media platforms. Last fall, NASA placed first by a wide margin in the L2 Digital IQ Index for the Public Sector study that ranks 100 public sector organizations in the effectiveness of their websites, digital outreach, social media use and mobile sites.

The Office of Communications and the Office of the Chief Information Officer, both at NASA Headquarters, manage the agency's website.

Presented by the International Academy of Digital Arts and Sciences, the Webby Award recognizes excellence in technology and creativity. The academy created the awards in 1996 to help drive the creative, technical, and professional progress of the Internet and evolving forms of interactive media. While members of the International Academy of Digital Arts and Sciences select the Webby award winners, the online community determines the winners of the People's Voice Awards.

To find all the ways you can connect and collaborate with NASA, visit: http://www.nasa.gov/connect.

The California Institute of Technology in Pasadena manages JPL for NASA.

NASA Technology Looks Inside Japan's Nuclear Reactor

2011-05-03T03:44:00.000-07:00

Design techniques honed at NASA's Jet Propulsion Laboratory in Pasadena, Calif., for Mars rovers were used to create the rover currently examining the inside of Japan's nuclear reactors, in areas not yet deemed safe for human crews.

The iRobot PackBot employs technologies used previously in the design of "Rocky-7," which served as a terrestrial test bed at JPL for the current twin Mars rovers, Spirit and Opportunity. PackBot's structural features are modeled after Rocky-7, including the lightweight, high-torque actuators that control the rover; and its strong, lightweight frame structure and sheet-metal chassis.

PackBot's other "ancestor," called Urbie, was an urban reconnaissance robot with military and disaster response applications. Urbie's lightweight structure and rugged features also made it useful in emergency response situations; for example, at sites contaminated with radiation and chemical spills, and at buildings damaged by earthquakes. Urbie's physical structure was designed by iRobot Corp., Bedford, Mass., while JPL was responsible for the intelligent robot's onboard sensors and vision algorithms, which helped the robot factor in obstacles and determine an appropriate driving path. Following the success of Urbie's milestones, the team at iRobot created its successor: PackBot.

Since 2002, iRobot has delivered variations of the PackBot model to the U.S. Army, U.S. Air Force and U.S. Navy. The tactical robot's first military deployment was to Afghanistan in July 2002, to assist soldiers by providing "eyes and ears" in the most dangerous or inaccessible areas. It was also used to search through debris at Ground Zero after the Sept. 11, 2001 attacks in New York.

Recently, iRobot provided two PackBots to help after the devastating March 11, 2011, earthquake and tsunami in Japan. The PackBot models, currently taking radioactivity readings in the damaged Fukushima Daiichi nuclear power plant buildings, are equipped with multiple cameras and hazard material sensors. The images and readings provided by the PackBots indicated radiation levels are still too high to allow human repair crews to safely enter the buildings.

Urbie was a joint effort of the Defense Advanced Research Project's Agency's (DARPA) Tactical Mobile Robot program, JPL, iRobot Corp., the Robotics Institute of Carnegie Mellon University, and the University of Southern California's Robotics Research Laboratory. JPL is managed for NASA by the California Institute of Technology in Pasadena.

For more information on the history of the partnership between iRobot and JPL, visit: http://www.sti.nasa.gov/tto/Spinoff2005/ps_1.html .

NASA Orbiter Reveals Big Changes in Mars' Atmosphere

2011-05-02T05:51:00.000-07:00

NASA's Mars Reconnaissance Orbiter has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet's axis varies.

This process can affect the stability of liquid water, if it exists on the Martian surface, and increase the frequency and severity of Martian dust storms.

Researchers using the orbiter's ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet's south pole. The scientists suspect that much of this carbon dioxide enters the planet's atmosphere and swells the atmosphere's mass when Mars' tilt increases. The findings are published in this week's issue of the journal Science.

The newly found deposit has a volume similar to Lake Superior's nearly 3,000 cubic miles (about 12,000 cubic kilometers). The deposit holds up to 80 percent as much carbon dioxide as today's Martian atmosphere. Collapse pits caused by dry ice sublimation and other clues suggest the deposit is in a dissipating phase, adding gas to the atmosphere each year. Mars' atmosphere is about 95 percent carbon dioxide, in contrast to Earth's much thicker atmosphere, which is less than .04 percent carbon dioxide.

"We already knew there is a small perennial cap of carbon-dioxide ice on top of the water ice there, but this buried deposit has about 30 times more dry ice than previously estimated," said Roger Phillips of Southwest Research Institute in Boulder, Colo. Phillips is deputy team leader for the Mars Reconnaissance Orbiter's Shallow Radar instrument and lead author of the report.

"We identified the deposit as dry ice by determining the radar signature fit the radio-wave transmission characteristics of frozen carbon dioxide far better than the characteristics of frozen water," said Roberto Seu of Sapienza University of Rome, team leader for the Shallow Radar and a co-author of the new report. Additional evidence came from correlating the deposit to visible sublimation features typical of dry ice.

"When you include this buried deposit, Martian carbon dioxide right now is roughly half frozen and half in the atmosphere, but at other times it can be nearly all frozen or nearly all in the atmosphere," Phillips said.

An occasional increase in the atmosphere would strengthen winds, lofting more dust and leading to more frequent and more intense dust storms. Another result is an expanded area on the planet's surface where liquid water could persist without boiling. Modeling based on known variation in the tilt of Mars' axis suggests several-fold changes in the total mass of the planet's atmosphere can happen on time frames of 100,000 years or less.

The changes in atmospheric density caused by the carbon-dioxide increase also would amplify some effects of the changes caused by the tilt. Researchers plugged the mass of the buried carbon-dioxide deposit into climate models for the period when Mars' tilt and orbital properties maximize the amount of summer sunshine hitting the south pole. They found at such times, global, year-round average air pressure is approximately 75 percent greater than the current level.

"A tilted Mars with a thicker carbon-dioxide atmosphere causes a greenhouse effect that tries to warm the Martian surface, while thicker and longer-lived polar ice caps try to cool it," said co-author Robert Haberle, a planetary scientist at NASA's Ames Research Center in Moffett Field, Calif. "Our simulations show the polar caps cool more than the greenhouse warms. Unlike Earth, which has a thick, moist atmosphere that produces a strong greenhouse effect, Mars' atmosphere is too thin and dry to produce as strong a greenhouse effect as Earth's, even when you double its carbon-dioxide content."

The Shallow Radar, one of the Mars Reconnaissance Orbiter's six instruments, was provided by the Italian Space Agency, and its operations are led by the Department of Information Engineering, Electronics and Telecommunications at Sapienza University of Rome. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter project for NASA's Science Mission Directorate at the agency's headquarters in Washington. Lockheed Martin Space Systems in Denver built the spacecraft.

JPL Tweetup Previews Missions: Mars, Jupiter and More

2011-04-29T04:08:00.000-07:00

NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., will host a Tweetup for approximately 120 Twitter followers on Monday, June 6 for the full day (roughly 9 a.m. to 5 p.m. PDT).

With four space missions launching this year and an asteroid belt encounter nearly underway, 2011 will be one of the busiest ever in planetary exploration. Tweetup participants will interact with JPL scientists and engineers about these upcoming missions: Aquarius, to study ocean salinity; Grail, to study the moon's gravity field; Juno to Jupiter; and the Mars Science Laboratory/Curiosity rover. Participants also will learn about the Dawn mission and its upcoming encounter with the asteroid Vesta.

The Tweetup will include a tour of JPL, robotics demonstrations and a last chance to see the Curiosity rover before it ships to Florida to prepare for a November launch. Tour stops will include the Spacecraft Assembly Facility, where Curiosity is under construction, the mission control center of NASA's Deep Space Network, and JPL's new Earth Science Visitor Center.

Tweetup participants also will mingle with fellow attendees and the staff behind the tweets on @NASA, @NASAJPL, @MarsRovers, @AsteroidWatch and more.

Registration for the event opens at noon PDT (3 p.m. EDT) on Tuesday, April 26, and it closes at noon PDT (3 p.m. EDT) on Wednesday, April 27. For more information about the Tweetup and to sign up, visit: http://www.nasa.gov/tweetup .

NASA Television will broadcast portions of the Tweetup on June 6 at: http://www.ustream.tv/channel/nasa-hd-tv and http://www.ustream.tv/nasajpl2 .

Find all the ways to connect and collaborate with NASA at: http://www.nasa.gov/connect
For more information about JPL, visit: http://www.nasa.gov/jpl . JPL is managed for NASA by the California Institute of Technology in Pasadena.

Ultraviolet Spotlight on Plump Stars in Tiny Galaxies

2011-04-27T01:50:00.000-07:00

Astronomers using NASA's Galaxy Evolution Explorer may be closer to knowing why some of the most massive stellar explosions ever observed occur in the tiniest of galaxies.

"It's like finding a sumo wrestler in a little 'Smart Car,'" said Don Neill, a member of NASA's Galaxy Evolution Explorer team at the California Institute of Technology in Pasadena, and lead author of a new study published in the Astrophysical Journal.

"The most powerful explosions of massive stars are happening in extremely low-mass galaxies. New data are revealing that the stars that start out massive in these little galaxies stay massive until they explode, while in larger galaxies they are whittled away as they age, and are less massive when they explode," said Neill.

Over the past few years, astronomers using data from the Palomar Transient Factory, a sky survey based at the ground-based Palomar Observatory near San Diego, have discovered a surprising number of exceptionally bright stellar explosions in so-called dwarf galaxies up to 1,000 times smaller than our Milky Way galaxy. Stellar explosions, called supernovae, occur when massive stars -- some up to 100 times the mass of our sun -- end their lives.

The Palomar observations may explain a mystery first pointed out by Neil deGrasse Tyson and John Scalo when they were at the University of Austin Texas (Tyson is now the director of the Hayden Planetarium in New York, N.Y.). They noted that supernovae were occurring where there seemed to be no galaxies at all, and they even proposed that dwarf galaxies were the culprits, as the Palomar data now indicate.

Now, astronomers are using ultraviolet data from the Galaxy Evolution Explorer to further examine the dwarf galaxies. Newly formed stars tend to radiate copious amounts of ultraviolet light, so the Galaxy Evolution Explorer, which has scanned much of the sky in ultraviolet light, is the ideal tool for measuring the rate of star birth in galaxies.

The results show that the little galaxies are low in mass, as suspected, and have low rates of star formation. In other words, the petite galaxies are not producing that many huge stars.

"Even in these little galaxies where the explosions are happening, the big guys are rare," said co-author Michael Rich of UCLA, who is a member of the mission team.

In addition, the new study helps explain why massive stars in little galaxies undergo even more powerful explosions than stars of a similar heft in larger galaxies like our Milky Way. The reason is that low-mass galaxies tend to have fewer heavy atoms, such as carbon and oxygen, than their larger counterparts. These small galaxies are younger, and thus their stars have had less time to enrich the environment with heavy atoms.

According to Neill and his collaborators, the lack of heavy atoms in the atmosphere around a massive star causes it to shed less material as it ages. In essence, the massive stars in little galaxies are fatter in their old age than the massive stars in larger galaxies. And the fatter the star, the bigger the blast that will occur when it finally goes supernova. This, according to the astronomers, may explain why super supernovae are occurring in the not-so-super galaxies.

"These stars are like heavyweight champions, breaking all the records," said Neill.

Added Rich, "These dwarf galaxies are especially interesting to astronomers, because they are quite similar to the kinds of galaxies that may have been present in our young universe, shortly after the Big Bang. The Galaxy Evolution Explorer has given us a powerful tool for learning what galaxies were like when the universe was just a child."

Caltech leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA's Jet Propulsion Laboratory in Pasadena manages the mission and built the science instrument. Caltech manages JPL for NASA. The mission was developed under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on this mission.

Graphics and additional information about the Galaxy Evolution Explorer are online at http://www.nasa.gov/galex/ and http://www.galex.caltech.edu .

Cassini Sees Saturn Electric Link With Enceladus

2011-04-26T01:50:00.001-07:00

NASA is releasing the first images and sounds of an electrical connection between Saturn and one of its moons, Enceladus.

The data collected by the agency's Cassini spacecraft enable scientists to improve their understanding of the complex web of interaction between the planet and its numerous moons. The results of the data analysis are published in the journals Nature

Scientists previously theorized an electrical circuit should exist at Saturn. After analyzing data that Cassini collected in 2008, scientists saw a glowing patch of ultraviolet light emissions near Saturn's north pole that marked the presence of a circuit, even though the moon is 240,000 kilometers (150,000 miles) away from the planet.

The patch occurs at the end of a magnetic field line connecting Saturn and its moon Enceladus. The area, known as an auroral footprint, is the spot where energetic electrons dive into the planet's atmosphere, following magnetic field lines that arc between the planet's north and south polar regions.

"The footprint discovery at Saturn is one of the most important fields and particle revelations from Cassini and ultimately may help us understand Saturn's strange magnetic field," said Marcia Burton, a Cassini fields and particles scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It gives us the first visual connection between Saturn and one of its moons."

The auroral footprint measures approximately 1,200 kilometers (750 miles) by less than 400 kilometers (250 miles), covering an area comparable to California or Sweden. At its brightest, the footprint shone with an ultraviolet light intensity far less than Saturn's polar auroral rings, but comparable to the faintest aurora visible at Earth without a telescope in the visible light spectrum. Scientists have not found a matching footprint at the southern end of the magnetic field line.
Jupiter's active moon Io creates glowing footprints near Jupiter's north and south poles, so scientists suspected there was an analogous electrical connection between Saturn and Enceladus. It is the only known active moon in the Saturn system with jets spraying water vapor and organic particles into space. For years, scientists used space telescopes to search Saturn's poles for footprints, but they found none.

"Cassini fields and particles instruments found particle beams aligned with Saturn's magnetic field near Enceladus, and scientists started asking if we could see an expected ultraviolet spot at the end of the magnetic field line on Saturn," said Wayne Pryor, a lead author of the Nature study released today, and Cassini co-investigator at Central Arizona College in Coolidge, Ariz. "We were delighted to find the glow close to the 'bulls-eye' at the center of our target."

In 2008, Cassini detected a beam of energetic protons near Enceladus aligned with the magnetic field and field-aligned electron beams. A team of scientists analyzed the data and concluded the electron beams had sufficient energy flux to generate a detectable level of auroral emission at Saturn. A few weeks later, Cassini captured images of an auroral footprint in Saturn's northern hemisphere. In 2009, a group of Cassini scientists led by Donald Gurnett at the University of Iowa in Iowa City, detected more complementary signals near Enceladus consistent with currents that travel from the moon to the top of Saturn's atmosphere, including a hiss-like sound from the magnetic connection. That paper was published in March in Geophysical Research Letters.

The water cloud above the Enceladus jets produces a massive, ionized "plasma" cloud through its interactions with the magnetic bubble around Saturn. This cloud disturbs the magnetic field lines. The footprint appears to flicker in these new data, so the rate at which Enceladus is spewing particles may vary.

"The new data are adding fuel to the fire of some long-standing debates about this active little moon," said Abigail Rymer, the other lead author of the Nature study and a Cassini team scientist based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Scientists have been wondering whether the venting rate is variable, and these new data suggest that it is."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and several of its instruments were designed, developed and assembled at JPL.

To see a video and hear the sounds of the electrical connection, and to get more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

JPL Director Charles Elachi Receives Multiple Honors

2011-04-25T02:23:00.000-07:00

The director of NASA's Jet Propulsion Laboratory, Charles Elachi, is receiving multiple awards and honors this year in the United States and overseas.

"I'm extremely pleased to receive all these honors, which reflect the groundbreaking research and projects I've had the opportunity to work on with my colleagues at Caltech, JPL and NASA through the years," Elachi said.

This week, Elachi accepted the 2011 General James E. Hill Lifetime Space Achievement Award from the Space Foundation. The award was presented at the National Space Symposium in Colorado Springs, Colo.

The award, named for the Space Foundation's former chairman, Gen. James E. Hill, USAF (retired), recognizes "outstanding individuals who have distinguished themselves through lifetime contributions to the welfare or betterment of humankind through exploration, development and use of space, or through use of space technology, information, themes or resources in academic, cultural, industrial or other pursuits of broad benefit to humanity."

On March 5, Elachi was presented with an honorary doctor of science degree by Occidental College in Los Angeles during its 40th annual President's Circle Dinner at JPL. Also in March, he received the American Astronautical Society's 2011 Carl Sagan Memorial Award at the organization's symposium in Greenbelt, Md. The award, presented in cooperation with the Planetary Society, is given to individuals who demonstrate leadership in research or policies advancing exploration of the cosmos.

In addition to the trio of awards he has accepted in the United States this year, Elachi is receiving two international honors.

He is being inducted into the French Legion, known as the Chevalier de la Legion d'Honneur. Although Elachi is a native of Lebanon, and the award is traditionally restricted to natives of France, the honor has been bestowed on foreign nationals "who have served France or the ideals it upholds." Being honored at age 16 as Lebanon's top science student enabled Elachi to attend the college of his choice, France's University of Grenoble, where he earned a bachelor's degree in physics in 1968. That same year, he received an engineering degree from the Polytechnic Institute in Grenoble, where he graduated first in the class.

"I'm very honored to be recognized with such a prestigious award," said Elachi, who will formally accept the honor for his life's work at a ceremony in the near future. "The years I spent in France, at the University of Grenoble and the Polytechnic Institute in Grenoble, were an important part of my life and helped pave the way for my career."

After studying in France, Elachi moved to Pasadena, where he received a master's (1969) and Ph.D. (1971) in electrical sciences from the California Institute of Technology. He also earned a master's degree (1983) in geology from UCLA and an MBA (1979) from USC.

Elachi noted that throughout his career, his links to France have continued through his research.

He joined JPL in 1970 as a researcher on various Earth and planetary missions. Elachi has been serving as JPL director since May 2001, and the decade since then has included such successful NASA space missions as the Mars Exploration Rovers Spirit and Opportunity, the Phoenix Mars Lander, Stardust, Spitzer, Kepler, and such Earth-orbiting satellites as Grace and Topex/Poseidon-Jason.

"Over the last three decades, JPL and the French Space Agency, working together, have revolutionized the field of oceanography by developing the capability to observe and monitor ocean currents on a global basis from space," Elachi said.

In addition to serving as JPL director, Elachi is vice president of Caltech, and an electrical engineering and planetary science professor. Caltech manages JPL for NASA.

Elachi has recently been listed in the top 10 on the Arabian Business Magazine "Power 500" list of the world's most influential people of Arab descent. The award looks at the influence of people from the Middle East in every sector: from the business world, media, entertainment, sports, science, arts and academia. Elachi is described as "one person who has driven mankind's thirst for knowledge about the other planets in our solar system."

NASA Marks Earth Day With Online Activities, Programs

2011-04-22T04:14:00.000-07:00

NASA and NASA's Jet Propulsion Laboratory, Pasadena, Calif., are celebrating the 41st anniversary of Earth Day this week with several online activities to engage the public in the agency's mission to use the vantage point of space to explore and protect our home planet.

Among the activities are two Web chats. On Thursday, April 21, JPL will host a pre-Earth Day Web video chat with a JPL scientist. Then on Earth Day, Friday, April 22, scientists involved in an airborne campaign in Greenland to monitor Arctic ice cover will participate in a second Web chat.

NASA maintains the world's largest contingent of dedicated Earth scientists and engineers to lead and assist other agencies in preserving the planet's environment.

For details on NASA Earth Day activities and new agency programs dedicated to expanding our knowledge of our home planet, visit: http://www.nasa.gov/earthday .

Student Video Chat with a NASA Earth Scientist

Thursday, April 21 (10-10:30 a.m. PDT) -- The JPL Education Office is hosting a live Web video chat with JPL scientist Annmarie Eldering, who will answer questions submitted in advance by middle school students. Eldering is the deputy project scientist for NASA's upcoming Orbiting Carbon Observatory 2 mission, which will measure carbon dioxide in the atmosphere. The chat will be broadcast live at: http://www.ustream.tv/nasajpl2/ .

NASA Chat: Live from the Top of the World

Friday, April 22 (noon-1 p.m. PDT) -- A team of Arctic explorers is in Greenland keeping a careful eye on changes in the ice landscape. Chat online with NASA's Lora Koenig from Kangerlussuag, Greenland, and Tom Wagner from NASA Headquarters in Washington about the Operation IceBridge airborne mission. The chat window opens at 11:30 a.m. PDT for advance registration. The chat will be broadcast live at: http://www.nasa.gov/connect/chat/live_from_greenland.html .

NASA Earth Day Video Contest 2011

Share your vision of what NASA's exploration of Earth means to you by creating a short YouTube video. NASA's Goddard Space Flight Center in Greenbelt, Md., announced on Wednesday a contest for the best video about discoveries or real-world benefits resulting from NASA's Earth science program. Producers are encouraged to draw from NASA's extensive collection of public domain Earth imagery. Submissions are due by May 27. For more information, visit: http://www.nasa.gov/topics/earth/features/earth-videos.html .

Additional NASA Center Activities

Marshall Space Flight Center, Huntsville, Ala., Thursday, April 21 (8 a.m.-10:30 a.m. PDT) -- Events organized around the theme "Sustainability" include ceremonial tree planting, announcement of photo contest winners, and exhibits by environmental vendors and organizations.

Ames Research Center, Mountain View, Calif., Wednesday-Friday, April 20-22 (3:30-4:30 p.m. PDT) -- Employees can tour the "Sustainability Base," a new facility that has re-purposed NASA technology designed for closed-loop systems in space. The project is a candidate for the platinum-plus rating by the internationally recognized LEED (Leadership in Energy and Environmental Design) green building certification system. For more information, visit: http://www.nasa.gov/externalflash/sustainability-base/index.html .

JPL is managed for NASA by the California Institute of Technology in Pasadena, Calif.

WISE Delivers Millions of Galaxies, Stars, Asteroids

2011-04-20T05:35:00.000-07:00

Astronomers across the globe can now sift through hundreds of millions of galaxies, stars and asteroids collected in the first bundle of data from NASA's Wide-field Infrared Survey Explorer (WISE) mission.

"Starting today thousands of new eyes will be looking at WISE data, and I expect many surprises," said Edward (Ned) Wright of UCLA, the mission's principal investigator.

WISE launched into space on Dec. 14, 2009 on a mission to map the entire sky in infrared light with greatly improved sensitivity and resolution over its predecessors. From its polar orbit, it scanned the skies about one-and-a-half times while collecting images taken at four infrared wavelengths of light. It took more than 2.7 million images over the course of its mission, capturing objects ranging from faraway galaxies to asteroids relatively close to Earth.

Like other infrared telescopes, WISE required coolant to chill its heat-sensitive detectors. When this frozen hydrogen coolant ran out, as expected, in early October, 2010, two of its four infrared channels were still operational. The survey was then extended for four more months, with the goal of finishing its sweep for asteroids and comets in the main asteroid belt of our solar system.

The mission's nearby discoveries included 20 comets, more than 33,000 asteroids between Mars and Jupiter, and 133 near-Earth objects (NEOs), which are those asteroids and comets with orbits that come within 28 million miles (about 45 million kilometers) of Earth's path around the sun. The satellite went into hibernation in early February of this year.

Today, WISE is taking the first major step in meeting its primary goal of delivering the mission's trove of objects to astronomers. Data from the first 57 percent of the sky surveyed is accessible through an online public archive. The complete survey, with improved data processing, will be made available in the spring of 2012. A predecessor to WISE, the Infrared Astronomical Satellite, served a similar role about 25 years ago, and those data are still valuable to astronomers today. Likewise, the WISE legacy is expected to endure for decades.

"We are excited that the preliminary data contain millions of newfound objects," said Fengchuan Liu, the project manager for WISE at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "But the mission is not yet over -- the real treasure is the final catalog available a year from now, which will have twice as many sources, covering the entire sky and reaching even deeper into the universe than today's release."

Astronomers will use WISE's infrared data to hunt for hidden oddities, and to study trends in large populations of known objects. Survey missions often result in the unexpected discoveries too, because they are looking everywhere in the sky rather than at known targets. Data from the mission are also critical for finding the best candidates for follow-up studies with other telescopes, including the European Space Agency's Herschel observatory, which has important NASA contributions.

"WISE is providing the newest-generation 'address book' of the infrared universe with the precise location and brightness of hundreds of millions of celestial objects," said Roc Cutri, lead scientist for WISE data processing at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, Calif. "WISE continues the long tradition of infrared sky surveys supported by Caltech, stretching back to the 1969 Two Micron Sky Survey."

So far, the WISE mission has released dozens of colorful images of the cosmos, in which infrared light has been assigned colors we see with our eyes. The whole collection can be seen at http://wise.ssl.berkeley.edu/gallery_images.html .

The public archive for astronomers is online at http://wise2.ipac.caltech.edu/docs/release/prelim/index.html. Instructions for astronomy enthusiasts wanting to try their hand at using the archive are at http://wise.ssl.berkeley.edu/wise_image_service.html.

JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

Tuning an 'Ear' to the Music of Gravitational Waves

2011-04-19T01:35:00.000-07:00

A team of scientists and engineers at NASA's Jet Propulsion Laboratory has brought the world one step closer to "hearing" gravitational waves -- ripples in space and time predicted by Albert Einstein in the early 20th century.

The research, performed in a lab at JPL in Pasadena, Calif., tested a system of lasers that would fly aboard the proposed space mission called Laser Interferometer Space Antenna, or LISA. The mission's goal is to detect the subtle, whisper-like signals of gravitational waves, which have yet to be directly observed. This is no easy task, and many challenges lie ahead.

The new JPL tests hit one significant milestone, demonstrating for the first time that noise, or random fluctuations, in LISA's laser beams can be hushed enough to hear the sweet sounds of the elusive waves.

"In order to detect gravitational waves, we have to make extremely precise measurements," said Bill Klipstein, a physicist at JPL. "Our lasers are much noisier than what we want to measure, so we have to remove that noise carefully to get a clear signal; it's a little like listening for a feather to drop in the middle of a heavy rainstorm." Klipstein is a co-author of a paper about the lab tests that appeared in a recent issue of Physical Review Letters.

The JPL team is one of many groups working on LISA, a joint European Space Agency and NASA mission proposal, which, if selected, would launch in 2020 or later. In August of this year, LISA was given a high recommendation by the 2010 U.S. National Research Council decadal report on astronomy and astrophysics.

One of LISA's primary goals is to detect gravitational waves directly. Studies of these cosmic waves began in earnest decades ago when, in 1974, researchers discovered a pair of orbiting dead stars -- a type called pulsars -- that were spiraling closer and closer together due to an unexplainable loss of energy. That energy was later shown to be in the form of gravitational waves. This was the first indirect proof of the waves, and ultimately earned the 1993 Nobel Prize in Physics.

LISA is expected to not only "hear" the waves, but also learn more about their sources -- massive objects such as black holes and dead stars, which sing the waves like melodies out to the universe as the objects accelerate through space and time. The mission would be able to detect gravitational waves from massive objects in our Milky Way galaxy as well as distant galaxies, allowing scientists to tune into an entirely new language of our universe.

The proposed mission would amount to a giant triangle of three distinct spacecraft, each connected by laser beams. These spacecraft would fly in formation around the sun, about 20 degrees behind Earth. Each one would hold a cube made of platinum and gold that floats freely in space. As gravitational waves pass by the spacecraft, they would cause the distance between the cubes, or test masses, to change by almost imperceptible amounts -- but enough for LISA's extremely sensitive instruments to be able to detect corresponding changes in the connecting laser beams.

"The gravitational waves will cause the 'corks' to bob around, but just by a tiny bit," said Glenn de Vine, a research scientist and co-author of the recent study at JPL. "My friend once said it's sort of like rubber duckies bouncing around in a bathtub."

The JPL team has spent the last six years working on aspects of this LISA technology, including instruments called phase meters, which are sophisticated laser beam detectors. The latest research accomplishes one of their main goals -- to reduce the laser noise detected by the phase meters by one billion times, or enough to detect the signal of gravitational waves.

The job is like trying to find a proton in a haystack. Gravitational waves would change the distance between two spacecraft -- which are flying at 5 million kilometers (3.1 million miles) apart -- by about a picometer, which is about 100 million times smaller than the width of a human hair. In other words, the spacecraft are 5,000,000,000 meters apart, and LISA would detect changes in that distance on the order of .000000000005 meters!

At the heart of the LISA laser technology is a process known as interferometry, which ultimately reveals if the distances traveled by the laser beams of light, and thus the distance between the three spacecraft, have changed due to gravitational waves. The process is like combining ocean waves -- sometimes they pile up and grow bigger, and sometimes they cancel each other out or diminish in size.

"We can't use a tape measure to get the distances between these spacecraft," said de Vine, "So we use lasers. The wavelengths of the lasers are like our tick marks on a tape measure."

On LISA, the laser light is detected by the phase meters and then sent to the ground, where it is "interfered" via data processing (the process is called time-delay interferometry for this reason -- there's a delay before the interferometry technique is applied). If the interference pattern between the laser beams is the same, then that means the spacecraft haven't moved relative to each other. If the interference pattern changes, then they did. If all other reasons for spacecraft movement have been eliminated, then gravitational waves are the culprit.

That's the basic idea. In reality, there are a host of other factors that make this process more complex. For one thing, the spacecraft don't stay put. They naturally move around for reasons that have nothing to do with gravitational waves. Another challenge is the laser beam noise. How do you know if the spacecraft moved because of gravitational waves, or if noise in the laser is just making it seem as if the spacecraft moved?

This is the question the JPL team recently took to their laboratory, which mimics the LISA system. They introduced random, artificial noise into their lasers and then, through a complicated set of data processing actions, subtracted most of it back out. Their recent success demonstrated that they could see changes in the distances between mock spacecraft on the order of a picometer.

In essence, they hushed the roar of the laser beams, so that LISA, if selected for construction, will be able to hear the universe softly hum a tune of gravitational waves.

Other authors of the paper from JPL are Brent Ware; Kirk McKenzie; Robert E. Spero and Daniel A. Shaddock, who has a joint post with JPL and the Australian National University in Canberra.

LISA is a proposed joint NASA and European Space Agency mission. The NASA portion of the mission is managed by NASA's Goddard Space Flight Center, Greenbelt, Md. Some of the key instrumentation studies for the mission are being performed at JPL. The U.S. mission scientist is Tom Prince at the California Institute of Technology in Pasadena. JPL is managed by Caltech for NASA.

NASA's Jupiter-Bound Spacecraft Arrives in Florida

2011-04-18T01:37:00.000-07:00

NASA's Juno spacecraft has arrived in Florida to begin final preparations for a launch this summer.

The spacecraft was shipped from Lockheed Martin Space Systems, Denver, to the Astrotech payload processing facility in Titusville, Fla., today. The solar-powered Juno spacecraft will orbit Jupiter's poles 33 times to find out more about the gas giant's origins, structure, atmosphere and magnetosphere.

"The Juno spacecraft and the team have come a long way since this project was first conceived in 2003," said Scott Bolton, Juno's principal investigator, based at Southwest Research Institute in San Antonio. "We're only a few months away from a mission of discovery that could very well rewrite the books on not only how Jupiter was born, but how our solar system came into being."

Next Monday, Juno will be removed from its shipping container, the first of the numerous milestones to prepare it for launch. Later that week, the spacecraft will begin functional testing to verify its state of health after the road trip from Colorado. After this, the team will load updated flight software and perform a series of mission readiness tests. These tests involve the entire spacecraft flight system, as well as the associated science instruments and the ground data system.

Juno will be carried into space aboard a United Launch Alliance Atlas V rocket lifting off from Launch Complex-41 at the Cape Canaveral Air Force Station in Florida. The launch period opens Aug. 5, 2011, and extends through Aug. 26. For an Aug. 5 liftoff, the launch window opens at 8:39 a.m. PDT (11:39 am EDT) and remains open through 9:39 a.m. PDT (12:39 p.m. EDT).

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute at San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, is building the spacecraft.

The Italian Space Agency in Rome is contributing an infrared spectrometer instrument and a portion of the radio science experiment. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.

WISE Mission Spots 'Horseshoe' Asteroid

2011-04-16T01:41:00.000-07:00

An asteroid recently discovered by NASA's Wide-field Infrared Survey Explorer (WISE) may be a bit of an oddball.

Most near-Earth asteroids -- NEAs for short -- have eccentric, or egg-shaped, orbits that take the asteroids right through the inner solar system. The new object, designated 2010 SO16, is different. Its orbit is almost circular such that it cannot come close to any other planet in the solar system except Earth.

However, even though the asteroid rides around with Earth, it never gets that close.

"It keeps well away from Earth," said Apostolos "Tolis" Christou, who, together with David Asher of the Armagh Observatory in Northern Ireland, analyzed the orbit of the body after it was discovered in infrared images taken by WISE. "So well, in fact, that it has likely been in this orbit for several hundred thousand years, never coming closer to our planet than 50 times the distance to the moon."

The asteroid is one of a few that trace out a horseshoe shape relative to Earth. As the asteroid approaches Earth, the planet's gravity causes the object to shift back into a larger orbit that takes longer to go around the sun than Earth. Alternately, as Earth catches up with the asteroid, the planet's gravity causes it to fall into a closer orbit that takes less time to go around the sun than Earth. The asteroid therefore never completely passes our planet. This slingshot-like effect results in a horseshoe-shaped path as seen from Earth, in which 2010 SO16 takes 175 years to get from one end of the horseshoe to the other.

"The origins of this object could prove to be very interesting," said Amy Mainzer of NASA's Jet Propulsion Laboratory, Pasadena, Calif., the principal investigator of NEOWISE, which is the asteroid- and comet-hunting portion of the WISE survey mission. "We are really excited that the astronomy community is already finding treasures in the NEOWISE data that have been released so far."

NEOWISE finished its one complete sweep of the solar system in early February of this year. Data on the orbits of asteroids and comets detected by the project, including near-Earth objects, are catalogued at the NASA-funded International Astronomical Union's Minor Planet Center, at the Smithsonian Astrophysical Observatory in Cambridge, Mass.

A full story from the Armagh Observatory, including animations, is online at http://www.arm.ac.uk/press/2011/aac_horseshoe_orbit.html.

JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md.

The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/, http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise .

Fast-Rotating Asteroid Winks For Astronomer's Camera

2011-04-15T01:37:00.000-07:00

Video imaging of newly discovered asteroid 2011 GP59 shows the object appearing to blink on and off about once every four minutes.

Amateur astronomers, including Nick James of Chelmsford, Essex, England, have captured video of the interesting object. James generated this video of GP59 on the night of Monday, April 11. The video, captured with an 11-inch Schmidt-Cassegrain telescope, is a compilation of 137 individual frames, each requiring 30 seconds of exposure.

At the time, the asteroid was approximately 3,356,000 kilometers (2,081,000 mile) distant. Since then, the space rock has become something of a darling of the amateur astronomy community, with many videos available. (Here is one recent posting: http://www.youtube.com/watch?v=O7wsAZNr56E )

"Usually, when we see an asteroid strobe on and off like that, it means that the body is elongated and we are viewing it broadside along its long axis first, and then on its narrow end as it rotates ," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "GP59 is approximately 50 meters [240 feet] long, and we think its period of rotation is about seven-and-a-half minutes. This makes the object's brightness change every four minutes or so."

2011 GP59 was discovered the night of April 8/9 by astronomers with the Observatorio Astronomico de Mallorca in Andalusia, Spain. It will make its closest approach to Earth on April 15 at 19:09 UTC (12:09 p.m. PDT) at a distance just beyond the moon's orbit - about 533,000 kilometers (331,000 miles).

"Although newly discovered, the near-term orbital location of asteroid 2011 GP59 can be accurately plotted," said Yeomans. "There is no possibility of the small space rock entering Earth's atmosphere during this pass or for the foreseeable future."

NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and plots their orbits to determine if any could be potentially hazardous to our planet.

JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.

More information about asteroids and near-Earth objects is at: http://www.jpl.nasa.gov/asteroidwatch .

NASA Telescopes Help Discover Surprisingly Young Galaxy

2011-04-14T03:10:00.000-07:00

Astronomers have uncovered one of the youngest galaxies in the distant universe, with stars that formed 13.5 billion years ago, a mere 200 million years after the Big Bang.

The finding addresses questions about when the first galaxies arose, and how the early universe evolved.

NASA's Hubble Space Telescope was the first to spot the newfound galaxy. Detailed observations from the W.M. Keck Observatory on Mauna Kea in Hawaii revealed the observed light dates to when the universe was only 950 million years old; the universe formed about 13.7 billion years ago.

Infrared data from both Hubble and the post-coolant, or "warm," phase of NASA's Spitzer Space Telescope mission revealed the galaxy's stars are quite mature, which means they must have formed when the universe was just a toddler.

"This challenges theories of how soon galaxies formed in the first years of the universe," said Johan Richard of the Centre de Recherche Astronomique de Lyon, Université Lyon 1 in France, lead author of a new study accepted for publication in the Monthly Notices of the Royal Astronomical Society. "It could even help solve the mystery of how the hydrogen fog that filled the early universe was cleared."

This galaxy is not the most distant ever observed, but it is one of the youngest to be observed with such clarity. Normally, galaxies like this one are extremely faint and difficult to study, but, in this case, nature has provided the astronomers with a cosmic magnifying glass. The galaxy's image is being magnified by the gravity of a massive cluster of galaxies parked in front of it, making it appear 11 times brighter. This phenomenon is called gravitational lensing.

"Without this big lens in space, we could not study galaxies this faint with currently available observing facilities," said co-author Eiichi Egami of the University of Arizona in Tucson. "Thanks to nature, we have this great opportunity to see our universe as it was eons ago."

The findings may help explain how the early universe became "reionized." At some point in our universe's early history, it transitioned from the so-called dark ages to a period of light, as the first stars and galaxies began to ignite. This starlight ionized neutral hydrogen atoms floating around in space, giving them a charge. Ultraviolet light could then travel unimpeded through what had been an obscuring fog.

The discovery of a galaxy possessing stars that formed only 200 million years after the big bang helps astronomers probe this cosmic reionization epoch. When this galaxy was developing, its hot, young stars would have ionized vast amounts of the neutral hydrogen gas in intergalactic space. A population of similar galaxies probably also contributed to this reionization, but they are too faint to see without the magnifying effects of gravitational lensing.

NASA's James Webb Space Telescope (JWST), scheduled to launch later this decade, will be able to see these faint galaxies lacking magnification. A successor to Hubble and Spitzer, JWST will see infrared light from the missing population of early galaxies. As a result, the mission will reveal some of our universe's best-kept secrets.

"Seeing a galaxy as it appeared near the beginning of the universe is an awe-inspiring feat enabled by innovative technology and the fortuitous effect of gravitational lensing," said Jon Morse, NASA's Astrophysics Division director at the agency's headquarters in Washington. "Observations like this open a window across space and time, but more importantly, they inspire future work to one day peer at the stars that lit up the universe following the big bang."

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer.

NASA's Jupiter-Bound Spacecraft Arrives in Florida

2011-04-13T01:38:00.000-07:00

NASA Telescope Ferrets Out Planet-Hunting Targets

2011-04-08T04:02:00.001-07:00

Astronomers have come up with a new way of identifying close, faint stars with NASA's Galaxy Evolution Explorer satellite.

The technique should help in the hunt for planets that lie beyond our solar system, because nearby, hard-to-see stars could very well be home to the easiest-to-see alien planets.

The glare of bright, shining stars has frustrated most efforts at visualizing distant worlds. So far, only a handful of distant planets, or exoplanets, have been directly imaged. Small, newborn stars are less blinding, making the planets easier to see, but the fact that these stars are dim means they are hard to find in the first place. Fortunately, the young stars emit more ultraviolet light than their older counterparts, which makes them conspicuous to the ultraviolet-detecting Galaxy Evolution Explorer.

"We've discovered a new technique of using ultraviolet light to search for young, low-mass stars near the Earth," said David Rodriguez, a graduate student of astronomy at UCLA, and lead author of a recent study. "These young stars make excellent targets for future direct imaging of exoplanets."

Tantrum-Throwing Baby Stars

Young stars, like human children, tend to be a bit unruly -- they spout a greater proportion of energetic X-rays and ultraviolet light than more mature stars. In some cases, X-ray surveys can pick out these youngsters due to the "racket" they cause. However, many smaller, less "noisy" baby stars perfect for exoplanet imaging studies have gone undetected except in the most detailed X-ray surveys. To date, such surveys have covered only a small percentage of the sky.

Rodriguez and his team figured the Galaxy Evolution Explorer, which has scanned about three-quarters of the sky in ultraviolet light, could fill this gap. Astronomers compared readings from the telescope with optical and infrared data to look for the telltale signature of rambunctious junior stars. Follow-up observations of 24 candidates identified in this manner determined that 17 of the stars showed clear signs of youth, validating the team's approach.

"The Galaxy Evolution Explorer can readily select young, low-mass stars that are too faint to turn up in all-sky X-ray surveys, which makes the telescope an incredibly useful tool," Rodriguez said.

Cool, Red and in the Neighborhood

Astronomers call the low-mass stars in question "M-class" stars. Also known as red dwarfs, these stars glow a relatively cool crimson color compared to the hotter oranges and yellows of stars like our sun, and the whites and blues of the most scorching stars. With data from the Galaxy Evolution Explorer, astronomers could reap a bounty of these red dwarfs still in their cosmic youth, under 100 million years old.

In many ways, these stars represent a best-case scenario for the direct imaging of exoplanets. They are close and in clear lines-of-sight, which generally makes viewing easier. Their low mass means they are dimmer than heavier stars, so their light is less likely to mask the feeble light of a planet. And because they are young stars, their planets are freshly formed, and thus warmer and brighter than older planetary bodies.

The Better to See Planets With

So far, only a handful of the more than 500 exoplanets on record have actually been "seen" by our ground- and space-based telescopes. The vast majority of foreign worlds have instead turned up via indirect means. One common technique, for instance, relies on detecting the slight gravitational "wobbles" exoplanets impart to their host stars. Another technique, the "transit method," registers the tiny dip in a star's light as an exoplanet crosses in front of it relative to our vantage point. NASA's Kepler mission, in just its first four months of operations, has already come up with a list of more than 1,200 candidate exoplanets using the transit method.

At a very basic level, directly imaging an exoplanet is worthwhile because, after all, "seeing is believing," Rodriguez said. But catching a glimpse of an exoplanet also opens up novel scientific avenues.

Direct imaging is well suited for seeing big planets circling host stars at considerable distances, comparable to Uranus and Neptune in our solar system. Observing such arrangements is useful for testing concepts of solar system evolution, Rodriguez said. Plus, gleaning details about the atmospheres of imaged exoplanets is less difficult than indirectly investigating worlds that transit their stars.

As for actually imaging clouds or surface features of exoplanets, however, that will have to wait. Current images of exoplanets, while full of information, resemble fuzzy dots. But as technology advances, ever more information about our close-by planetary brethren will emerge.

Data from NASA's Wide-field Infrared Survey Explorer (WISE) mission could also reveal stars that would make good candidates for imaging planets. Its all-sky maps will allow scientists to pick out nearby, young stars surrounded by warm disks of planetary debris that glow with infrared light. Such stars are similar to the ones where planets have already been successfully imaged.

The new study was published in the February issue of The Astrophysical Journal and includes co-authors Mike Bessell (Australian National University), Ben Zuckerman (UCLA), and Joel Kastner (Rochester Institute of Technology).

The California Institute of Technology in Pasadena leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA's Jet Propulsion Laboratory, also in Pasadena, manages the mission and built the science instrument. Caltech manages JPL for NASA. The mission was developed under NASA's Explorers Program managed by NASA's Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on this mission.

Additional information about the Galaxy Evolution Explorer are online at http://www.galex.caltech.edu and http://www.nasa.gov/galex .

The Art of Making Stars

2011-04-07T02:55:00.000-07:00

It might look like an abstract painting, but this splash of colors is in fact a busy star-forming complex called Rho Ophiuchi.

NASA's Wide-field Infrared Explorer, or WISE, captured the picturesque image of the region, which is one of the closest star-forming complexes to Earth.

The amazing variety of colors seen in this image represents different wavelengths of infrared light. The bright white nebula in the center of the image is glowing due to heating from nearby stars, resulting in what is called an emission nebula. The same is true for most of the multi-hued gas prevalent throughout the entire image, including the bluish, bow-shaped feature near the bottom right.

The bright red area in the bottom right is light from the star in the center – Sigma Scorpii – that is reflected off of the dust surrounding it, creating what is called a reflection nebula. And the much darker areas scattered throughout the image are pockets of cool, dense gas that block out the background light, resulting in absorption (or 'dark') nebulae. WISE's longer wavelength detectors can typically see through dark nebulae, but these are exceptionally opaque.

JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md.

The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise .

Winter thaws out with hot exoplanet news

2011-04-06T02:57:00.000-07:00

To date the search for habitable Earth-like planets has primarily focused on nuclear burning stars. I propose that this search should be expanded to cool white dwarf stars that have expended their nuclear fuel.

I define the continuously habitable zone of white dwarfs, and show that it extends from ~0.005 to 0.02 AU for white dwarfs with masses from 0.4 to 0.9 solar masses, temperatures less than 10,000 K, and habitable durations of at least 3 Gyr. As they are similar in size to Earth, white dwarfs may be deeply eclipsed by terrestrial planets that orbit edge-on, which can easily be detected with ground-based telescopes.

If planets can migrate inward or reform near white dwarfs, I show that a global robotic telescope network could carry out a transit survey of nearby white dwarfs placing interesting constraints on the presence of habitable Earths. If planets were detected, I show that the survey would favor detection of planets similar to Earth: similar size, temperature, rotation period, and host star temperatures similar to the Sun.

The Large Synoptic Survey Telescope could place even tighter constraints on the frequency of habitable Earths around white dwarfs. The confirmation and characterization of these planets might be carried out with large ground and space telescopes.

NASA Airborne Radar Set to Image Hawaiian Volcano

2011-04-05T02:06:00.000-07:00

The Kilauea volcano that recently erupted on the Big Island of Hawaii will be the target for a NASA study to help scientists better understand processes occurring under Earth's surface.

A NASA Gulfstream-III aircraft equipped with a synthetic aperture radar developed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., is scheduled to depart Sunday, April 3, from the Dryden Aircraft Operations Facility in Palmdale, Calif., to the Big Island for a nine-day mission.

The Uninhabited Aerial Vehicle Synthetic Aperture Radar, or UAVSAR, uses a technique called interferometric synthetic aperture radar that sends pulses of microwave energy from the aircraft to the ground to detect and measure very subtle deformations in Earth's surface, such as those caused by earthquakes, volcanoes, landslides and glacier movements.

As the Gulfstream-III flies at an altitude of about 12,500 meters (41,000 feet), the radar, located in a pod under the aircraft's belly, will collect data over Kilauea. The UAVSAR's first data acquisitions over this volcanic region took place in January 2010, when the radar flew over the volcano daily for a week. The UAVSAR detected deflation of Kilauea's caldera over one day, part of a series of deflation-inflation events observed at Kilauea as magma is pumped into the volcano's east rift zone.

This month's flights will repeat the 2010 flight paths to an accuracy of within 5 meters, or about 16.5 feet, assisted by a Platform Precision Autopilot designed by engineers at NASA's Dryden Flight Research Center on Edwards Air Force Base, Calif. By comparing these camera-like images, interferograms are formed that reveal changes in Earth's surface.

Between March 5 and 11, 2011, a spectacular fissure eruption occurred along the east rift zone. Satellite radar imagery captured the progression of this volcanic event.

"The April 2011 UAVSAR flights will capture the March 2011 fissure eruption surface displacements at high resolution and from multiple viewing directions, giving us an improved resolution of the magma injected into the east rift zone that caused the eruption," said JPL research scientist Paul Lundgren.

This injection of magma takes the form of a dike, a thin blade-like sheet of magma extending from the surface to several kilometers depth, with an opening of only a few meters.

"Our goal is to be able to deploy the UAVSAR on short notice to better understand and aid in responding to hazards from Kilauea and other volcanoes in the Pacific region covered by this study," Lundgren added.

For more on UAVSAR, visit: http://uavsar.jpl.nasa.gov . For more information about NASA's G-III Earth science research aircraft, visit: http://www.nasa.gov/centers/dryden/news/FactSheets/FS-089-DFRC.html .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

Forensic Sleuthing Ties Ring Ripples to Impacts

2011-04-04T03:44:00.001-07:00

Like forensic scientists examining fingerprints at a cosmic crime scene, scientists working with data from NASA's Cassini, Galileo and New Horizons missions have traced telltale ripples in the rings of Saturn and Jupiter back to collisions with cometary fragments dating back more than 10 years ago.

The ripple-producing culprit, in the case of Jupiter, was comet Shoemaker-Levy 9, whose debris cloud hurtled through the thin Jupiter ring system during a kamikaze course into the planet in July 1994. Scientists attribute Saturn's ripples to a similar object – likely another cloud of comet debris -- plunging through the inner rings in the second half of 1983. The findings are detailed in a pair of papers published online today in the journal Science.

"What's cool is we're finding evidence that a planet's rings can be affected by specific, traceable events that happened in the last 30 years, rather than a hundred million years ago," said Matthew Hedman, a Cassini imaging team associate, lead author of one of the papers, and a research associate at Cornell University, Ithaca, N.Y. "The solar system is a much more dynamic place than we gave it credit for."

From Galileo's visit to Jupiter, scientists have known since the late 1990s about patchy patterns in the Jovian ring. But the Galileo images were a little fuzzy, and scientists didn't understand why such patterns would occur. The trail was cold until Cassini entered orbit around Saturn in 2004 and started sending back thousands of images. A 2007 paper by Hedman and colleagues first noted corrugations in Saturn's innermost ring, dubbed the D ring.

A group including Hedman and Mark Showalter, a Cassini co-investigator based at the SETI Institute in Mountain View, Calif., then realized that the grooves in the D ring appeared to wind together more tightly over time. Playing the process backward, Hedman then demonstrated the pattern originated when something tilted the D ring off its axis by about 100 meters (300 feet) in late 1983. The scientists found the influence of Saturn's gravity on the tilted area warped the ring into a tightening spiral.

Cassini imaging scientists got another clue when the sun shone directly along Saturn's equator and lit the rings edge-on in August 2009. The unique lighting conditions highlighted ripples not previously seen in another part of the ring system. Whatever happened in 1983 was not a small, localized event; it was big.

The collision had tilted a region more than 19,000 kilometers (12,000 miles) wide, covering part of the D ring and the next outermost ring, called the C ring. Unfortunately spacecraft were not visiting Saturn at that time, and the planet was on the far side of the sun, hidden from telescopes on or orbiting Earth, so whatever happened in 1983 passed unnoticed by astronomers.

Hedman and Showalter, the lead author on the second paper, began to wonder whether the long-forgotten pattern in Jupiter's ring system might illuminate the mystery. Using Galileo images from 1996 and 2000, Showalter confirmed a similar winding spiral pattern. They applied the same math they had applied to Saturn – but now with Jupiter's gravitational influence factored in.

Unwinding the spiral pinpointed the date when Jupiter's ring was tilted off its axis: between June and September 1994. Shoemaker-Levy plunged into the Jovian atmosphere during late July 1994. The estimated size of the nucleus was also consistent with the amount of material needed to disturb Jupiter's ring.

The Galileo images also revealed a second spiral, which was calculated to have originated in 1990. Images taken by New Horizons in 2007, when the spacecraft flew by Jupiter on its way to Pluto, showed two newer ripple patterns, in addition to the fading echo of the Shoemaker-Levy impact.

"We now know that collisions into the rings are very common – a few times per decade for Jupiter and a few times per century for Saturn," Showalter said. "Now scientists know that the rings record these impacts like grooves in a vinyl record, and we can play back their history later."

The ripples also give scientists clues to the size of the clouds of cometary debris that hit the rings. In each of these cases, the nuclei of the comets – before they likely broke apart – were a few kilometers wide.

"Finding these fingerprints still in the rings is amazing and helps us better understand impact processes in our solar system," said Linda Spilker, Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Cassini's long sojourn around Saturn has helped us tease out subtle clues that tell us about the history of our origins."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.

The imaging team is based at the Space Science Institute in Boulder, Colo. JPL managed the Galileo mission for NASA, and designed and built the Galileo orbiter. The New Horizons mission is led by Principal Investigator Alan Stern of Southwest Research Institute, Boulder, Colo., and managed by the Johns Hopkins Applied Physics Laboratory, Laurel, Md., for NASA's Science Mission Directorate.

More information about Cassini can be found at http://www.nasa.gov/cassini .

Future Engineers Unite at Robotics Competition

2011-04-01T06:20:00.000-07:00

The 20th season of the Los Angeles regional FIRST (For Inspiration and Recognition of Science and Technology) Robotics Competition, held at the Long Beach Convention Center, March 25 and 26, proved to be a fierce competition between 63 high school teams from across California and as far away as Chile.

Students from three California schools – South High School, Torrance; West Covina High School, West Covina; and Diamond Bar High School, Diamond Bar, won the overall regional competition. Two other California schools also took top honors. Chaminade College Preparatory, West Hills, receied the coveted Regional Chairman's award, while Foshay Learning Center, Los Angeles, a team mentored by NASA's Jet Propulsion Laboratory in Pasadena, Calif., took home the Engineering Inspiration award.

The winners will represent the California region at the FIRST championships April 27 to 30 in St. Louis, where they will compete against 51,000 other students on more than 2,000 teams.

The FIRST program was founded two decades ago to encourage students to pursue careers in science and technology through robotics competitions. With the help of engineers from JPL, aerospace and other companies and institutions of higher education, FIRST continues to grow and inspire students.

For more information, visit: http://www.usfirst.org/ .

NASA Announces 2011 Carl Sagan Fellows

2011-03-30T04:52:00.000-07:00

NASA has selected five potential discoverers as the recipients of the 2011 Carl Sagan Postdoctoral Fellowships, named after the late astronomer. The Carl Sagan Fellowship takes a theme-based approach, in which fellows will focus on compelling scientific questions, such as "Are there Earth-like planets orbiting other stars?"

Sagan once said, "Somewhere, something incredible is waiting to be known," which is in line with the Sagan Fellowship's primary goal: to discover and characterize planetary systems and Earth-like planets around other stars. Planets outside of our solar system are called exoplanets. The fellowship also aims to support outstanding recent postdoctoral scientists in conducting independent research broadly related to the science goals of NASA's Exoplanet Exploration Program.

Previous Sagan Fellows have contributed significant discoveries in exoplanet exploration. including: the first characterizations of a super-Earth's atmosphere using a ground-based telescope; and the discovery of a massive disk of dust and gas encircling a giant young star, which could potentially answer the long-standing question of how massive stars are born.

"The Sagan Fellowship program seeks to identify the most highly qualified young researchers in the field of exoplanets. Nowhere is the dynamism of this young branch of astronomy demonstrated more dramatically than by the intellectual quality and enthusiasm of these five new Sagan Fellows," said Charles Beichman, executive director of the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena. "These scientists are certain to be leaders of this exciting and rapidly growing field for many years to come."

The program, created in 2008, awards selected postdoctoral scientists with annual stipends of approximately $64,500 for up to three years, plus an annual research budget of up to $16,000. Topics range from techniques for detecting the glow of a dim planet in the blinding glare of its host star, to searching for the crucial ingredients of life in other planetary systems.

The 2011 Sagan Fellows are:

-- David Kipping, who will work at the Harvard-Smithsonian Center for Astrophysics, Cambridge, to combine theory and observation to conduct a search for the moons of exoplanets.

-- Bryce Croll, who will work at the Massachusetts Institute of Technology, Cambridge, Mass., to characterize the atmospheres of both large and small exoplanets using a variety of telescopes.

-- Wladimir Lyra, who will work at NASA's Jet Propulsion Laboratory, Pasadena, Calif., to study planet-forming disks and exoplanet formation.

-- Katie Morzinski, who will work at the University of Arizona, Tucson, to commission and employ high-contrast adaptive optics systems that will directly image Jupiter-like exoplanets.

-- Sloane Wiktorowicz, who will work at the University of California, Santa Cruz to use a technique called optical polarimetry to directly detect exoplanets.

NASA has two other astrophysics theme-based fellowship programs: the Einstein Fellowship Program, which supports research into the physics of the cosmos, and the Hubble Fellowship Program, which supports research into cosmic origins. The Sagan Fellowship Program is administered by the NASA Exoplanet Science Institute as part of NASA's Exoplanet Exploration Program at JPL in Pasadena, Calif. The California Institute of Technology manages JPL for NASA.

Cassini Finds Saturn Sends Mixed Signals

2011-03-28T02:20:00.000-07:00

Recent data from NASA's Cassini spacecraft show that the variation in radio waves controlled by the planet's rotation is different in the northern and southern hemispheres.

Moreover, the northern and southern rotational variations also appear to change with the Saturnian seasons, and the hemispheres have actually swapped rates. These two radio waves, converted to the human audio range, can be heard in a new video available online at: http://www.nasa.gov/multimedia/videogallery/index.html?media_id=74390781

"These data just go to show how weird Saturn is," said Don Gurnett, Cassini's radio and plasma wave science instrument team lead and professor of physics at the University of Iowa, Iowa City. "We thought we understood these radio wave patterns at gas giants, since Jupiter was so straightforward. Without Cassini's long stay, scientists wouldn't have understood that the radio emissions from Saturn are so different."

Saturn emits radio waves known as Saturn Kilometric Radiation, or SKR for short. To Cassini, they sound a bit like bursts of a spinning air raid siren, since the radio waves vary with each rotation of the planet. This kind of radio wave pattern had been previously used at Jupiter to measure the planet's rotation rate, but at Saturn, as is the case with teenagers, the situation turned out to be much more complicated.

When NASA's Voyager spacecraft visited Saturn in the early 1980s, the radiation emissions indicated the length of Saturn's day was about 10.66 hours. But as its clocking continued by a flyby of the joint ESA-NASA Ulysses spacecraft and Cassini, the radio burst varied by seconds to minutes. A paper in Geophysical Research Letters in 2009 analyzing Cassini data showed that the Saturn Kilometric Radiation was not even a solo, but a duet, with two singers out of sync. Radio waves emanating from near the north pole had a period of around 10.6 hours; radio waves near the south pole had a period of around 10.8 hours.

A new paper led by Gurnett that was published in Geophysical Research Letters in December 2010 shows that, in recent Cassini data, the southern and northern SKR periods crossed over around March 2010, about seven months after equinox, when the sun shines directly over a planet's equator. The southern SKR period decreased from about 10.8 hours on Jan. 1, 2008 and crossed with the northern SKR period around March 1, 2010, at around 10.67 hours. The northern period increased from about 10.58 hours to that convergence point.

Seeing this kind of crossover led the Cassini scientists to go back into data from previous Saturnian visits. With a new eye, they saw that NASA's Voyager data taken in 1980, about a year after Saturn's 1979 equinox, showed different warbles from Saturn's northern and southern poles. They also saw a similar kind of effect in the Ulysses radio data between 1993 and 2000. The northern and southern periods detected by Ulysses converged and crossed over around August 1996, about nine months after the previous Saturnian equinox.

Cassini scientists don't think the differences in the radio wave periods had to do with hemispheres actually rotating at different rates, but more likely came from variations in high-altitude winds in the northern and southern hemispheres. Two other papers involving Cassini investigators were published in December, with results complementary to the radio and plasma wave science instrument -- one by Jon Nichols, University of Leicester, U.K., in the same issue of Geophysical Research Letters, and the other led by David Andrews, also of University of Leicester, in the Journal of Geophysical Research.

In the Nichols paper, data from the NASA/ESA Hubble Space Telescope showed the northern and southern auroras on Saturn wobbled back and forth in latitude in a pattern matching the radio wave variations, from January to March 2009, just before equinox. The radio signal and aurora data are complementary because they are both related to the behavior of the magnetic bubble around Saturn, known as the magnetosphere. The paper by Andrews, a Cassini magnetometer team associate, showed that from mid-2004 to mid-2009, Saturn's magnetic field over the two poles wobbled at the same separate periods as the radio waves and the aurora.

"The rain of electrons into the atmosphere that produces the auroras also produces the radio emissions and affects the magnetic field, so scientists think that all these variations we see are related to the sun's changing influence on the planet," said Stanley Cowley, a co-author on both papers, co-investigator on Cassini's magnetometer instrument, and professor at the University of Leicester.

As the sun continues to climb towards the north pole of Saturn, Gurnett's group has continued to see the crossover trend in radio signals through Jan. 1, 2011. The period of the southern radio signals continued to decrease to about 10.54 hours, while the period of the northern radio signals increased to 10.71 hours.

"These papers are important in helping to explain the complicated dance between the sun and Saturn's magnetic bubble, something normally invisible to the human eye and imperceptible to the human ear," said Marcia Burton, a Cassini fields and particles scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., who was not involved in the work. "Cassini will continue to keep an eye on these changes."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. The magnetometer team is based at Imperial College, London, U.K.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

Juno Marches On

2011-03-25T04:00:00.000-07:00

NASA's Juno spacecraft has completed its thermal vacuum chamber testing. The two-week-long test, which concluded on March 13, 2011, is the longest the spacecraft will undergo prior to launch.

In the image, a technician is attaching the lifting equipment in preparation for hoisting the 1,588-kilogram (3,500-pound) spacecraft out of the chamber. Prominent in the photo is one of three large, black, square solar array simulators, which reproduced the thermal properties of Juno's large solar arrays.

The actual solar arrays Juno will use to power the spacecraft during its voyage to, and its exploration of, Jupiter have already been shipped to NASA's Kennedy Space Center in Florida. The main body of the Juno spacecraft, including its suite of science instruments, is scheduled to ship to Kennedy in early April, where it will undergo final preparations and launch.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute at San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala.

Lockheed Martin Space Systems, Denver, is building the spacecraft. The Italian Space Agency in Rome is contributing an infrared spectrometer instrument and a portion of the radio science experiment. JPL is a division of the California Institute of Technology in Pasadena.

Stars Gather in 'Downtown' Milky Way

2011-03-24T01:39:00.000-07:00

The region around the center of our Milky Way galaxy glows colorfully in this new version of an image taken by NASA's Spitzer Space Telescope.

The data were previously released as part of a long, 120-degree view of the plane our galaxy (see http://www.spitzer.caltech.edu/images/2680-ssc2008-11a-Spitzer-Finds-Clarity-in-the-Inner-Milky-Way). Now, data from the very center of that picture are being presented at a different contrast to better highlight this jam-packed region. In visible-light pictures, it is all but impossible to see the heart of our galaxy, but infrared light penetrates the shroud of dust giving us this unprecedented view.

In this Spitzer image, the myriad of stars crowding the center of our galaxy creates the blue haze that brightens towards the center of the image. The green features are from carbon-rich dust molecules, called polycyclic aromatic hydrocarbons, which are illuminated by the surrounding starlight as they swirl around the galaxy's core. The yellow-red patches are the thermal glow from warm dust. The polycyclic aromatic hydrocarbons and dust are associated with bustling hubs of young stars. These materials, mixed with gas, are required for making new stars.

The brightest white feature at the center of the image is the central star cluster in our galaxy. At a distance of 26,000 light years away from Earth, it is so distant that, to Spitzer's view, most of the light from the thousands of individual stars is blurred into a single glowing blotch. Astronomers have determined that these stars are orbiting a massive black hole that lies at the very center of the galaxy.

The region pictured here is immense, with a horizontal span of 2,400 light-years (5.3 degrees) and a vertical span of 1,360 light-years (3 degrees). Though most of the objects seen in this image are located near the galactic center, the features above and below the galactic plane tend to lie closer to Earth.

The image is a three-color composite, showing infrared observations from two of Spitzer instruments. Blue represents 3.6-micron light and green shows 8-micron light, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer. The data is a combination of observations from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) project, and the Multiband Imaging Photometer for Spitzer Galactic survey (MIPSGAL).

Alternatives Have Begun in Bid to Hear from Spirit

2011-03-23T01:39:00.000-07:00

Hopes for reviving NASA's Spirit Mars rover dimmed further with passage last week of the point at which the rover's locale received its maximum sunshine for the Martian year.

The rover team has tried to contact Spirit for months with strategies based on the possibility that increasing energy availability might wake the rover from hibernation. The team has now switched to communication strategies designed to address more than one problem on the rover. If no signal is heard from Spirit in the next month or two, the team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., will shift to single-rover operations, continuing to operate Spirit's active twin, Opportunity.

"The commands we are sending starting this week should work in a multiple-fault scenario where Spirit's main transmitter is no longer working and the mission clock has lost track of time or drifted significantly," said JPL's John Callas, project manager for Spirit and Opportunity.

Spirit landed on Mars Jan. 4, 2004 Universal Time (Jan. 3, Pacific Time) for a mission designed to last for three months. After accomplishing its prime-mission goals, Spirit worked for more than five years in bonus-time extended missions.

Spirit has not communicated since March 22, 2010. Power output from its solar array had been waning prior to that, and the rover had been expected to go into a low-power hibernation mode. With drive motors on two of its six wheels no longer working, Spirit had been unable in preceding months to maneuver much in its sand-trap location. The rover could not get to a favorable tilt for its solar panels as Martian winter approached.

During the Martian winter with most heaters turned off, Spirit experienced colder internal temperatures than in any of its three previous winters on Mars. The cold could have damaged any of several electronic components that, if damaged, would prevent reestablishing communication with Spirit.

However, attempts to regain contact have continued for more than eight months in the possibility that the seasonal increase in solar energy available at Spirit's location would revive the rover. NASA's Deep Space Network of antennas in California, Spain and Australia has been listening for Spirit daily. The rover team has also sent commands to elicit a response from the rover even if the rover has lost track of time, or if its receiver has degraded in frequency response.

The available solar energy at Spirit's site was estimated to peak on March 10. Revised commanding began March 15, including instructions for the rover to be receptive over UHF relay to hailing from the Mars orbiters for extended periods of time and to use a backup transmitter on the rover.

Spirit and Opportunity both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Opportunity landed three weeks after Spirit.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Science Mission Directorate, Washington.

NASA Picks a Festive Clover of Ireland Images

2011-03-21T06:09:00.000-07:00

March 17 marks St. Patrick's Day —a day when shamrocks, Ireland and "wearing of the green" are especially in vogue. To celebrate this festive occasion, NASA's Aqua satellite has picked a clover of different views of the Emerald Isle, Ireland.

The collection of images acquired by Aqua's Atmospheric Infrared Sounder (AIRS) instrument on March 3, 2011, includes near-infrared/visible, infrared and microwave light views of the land where St. Patrick's Day originated.

The AIRS instrument measures temperatures of land, sea and air to provide a better understanding of what is happening in those environments.

The clover of AIRS images reveal temperatures near Earth's surface that were near normal for this time of year. The visible image showed a mostly cloud-free country blanketed by an approaching cold front. The infrared image showed low western clouds associated with a cold front moving east. The microwave brightness temperature data are a bit colder than the infrared temperature data, 273 Kelvin, which is just at the freezing point of water (0 degrees Celsius, or 32 degrees Fahrenheit).

For more information about these images, visit: http://www.nasa.gov/topics/earth/features/aqua-clover.html .

AIRS observes and records the global daily distribution of temperature, water vapor, clouds and several atmospheric gases, including ozone, methane and carbon monoxide. For more on AIRS, see http://airs.jpl.nasa.gov/ .

Students Compete in Lego Robotics Challenge at JPL

2011-03-18T04:48:00.000-07:00

Near a testing chamber at NASA's Jet Propulsion Laboratory, where a team of technicians are preparing and testing NASA's next Mars rover, students from across Southern California gathered to compete in a robotics challenge that simulated planetary exploration using table-top sized robots made out of Lego pieces.

The school teams spent months creating small Lego robots programmed with special software for this contest, which included placing sensors in "volcanoes," deploying habitats and rescuing a stranded "moon buggy." The robotic competition aims to engage students in math, science, technology and engineering. Each team had four students. The contest was divided into two sections: one for elementary-school teams, and the other for middle- and high-school teams.

In between the competition rounds and the awards ceremony, JPL robotics engineer Paulo Younse gave the students a special presentation on robotics at JPL featuring a video on Mars Science Laboratory, which features the rover named Curiosity, and how it works.

The Lego Robotics competition was streamed live on the Web. A video of the event can be viewed at http://livestre.am/F8jU .

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory mission for the NASA Science Mission Directorate, Washington.

For more information about the next mission to Mars, visit http://mars.jpl.nasa.gov/msl/ .

More information about robotics programs for students can be found online at http://www.usfirst.org/roboticsprograms/fll/default.aspx .

List of Winners:

ELEMENTARY DIVISION
1st place: "The ThunderBots," Northridge Magnet School, Moreno Valley
2nd place: "...Bot Bunch V," Sycamore Hills Elementary School, Fontana
3rd place: "Rockin' Robots," Lake View Elementary, Huntington Beach

SECONDARY DIVISION
1st place: "Team Cocoa," Mesa Union School, Somis
2nd place: "Team Down Loadable Content," Roosevelt Middle School, Glendale
3rd place: "Robots Taking Over, " Charles T. Kranz Intermediate School, El Monte

INGENUITY AWARD
"Team Down Loadable Content, " Roosevelt Middle School, Glendale

BEST ROBOT DESIGN AWARD
"Team Cocoa," Mesa Union School, Somis

AGAINST ALL ODDS AWARD
"Steam Rollers," Lake View Elementary School, Huntington Beach

Speed Demon Creates a Shock

2011-03-17T01:46:00.000-07:00

Just as some drivers obey the speed limit while others treat every road as if it were the Autobahn, some stars move through space faster than others.

NASA's Wide-field Infrared Survey Explorer, or WISE, captured this image of the star Alpha Camelopardalis, or Alpha Cam, in astronomer-speak, speeding through the sky like a motorcyclist zipping through rush-hour traffic. The supergiant star Alpha Cam is the bright star in the middle of this image, surrounded on one side by an arc-shaped cloud of dust and gas -- a bow shock -- which is colored red in this infrared view.

Such fast-moving stars are called runaway stars. The distance and speed of Alpha Cam is somewhat uncertain. It is probably somewhere between 1,600 and 6,900 light-years away and moving at an astonishing rate of somewhere between 680 and 4,200 kilometers per second (between 1.5 and 9.4 million mph).

It turns out that WISE is particularly adept at imaging bow shocks from runaway stars. Previous examples can be seen around Zeta Ophiuchi , AE Aurigae, and Menkhib. But Alpha Cam revs things up into a different gear. To put its speed into perspective, if Alpha Cam were a car driving across the United States at 4,200 kilometers per second, it would take less than one second to travel from San Francisco to New York City!

Astronomers believe runaway stars are set into motion either through the supernova explosion of a companion star or through gravitational interactions with other stars in a cluster. Because Alpha Cam is a supergiant star, it gives off a very strong wind. The speed of the wind is boosted in the forward direction the star is moving in space.

When this fast-moving wind slams into the slower-moving interstellar material, a bow shock is created, similar to the wake in front of the bow of a ship in water. The stellar wind compresses the interstellar gas and dust, causing it to heat up and glow in infrared. Alpha Cam's bow shock cannot be seen in visible light, but WISE's infrared detectors show us the graceful arc of heated gas and dust around the star.

JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md.

The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise .

Japan Quake May Have Shortened Earth Days, Moved Axis

2011-03-16T03:15:00.000-07:00

The March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day and shifted its axis. But don't worry-you won't notice the difference.

Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake-the fifth largest since 1900-affected Earth's rotation.

His calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).

The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth's figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth's axis in space-only external forces such as the gravitational attraction of the sun, moon and planets can do that.

Both calculations will likely change as data on the quake are further refined.

In comparison, following last year's magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth's figure axis by about 8 centimeters (3 inches).

A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth's figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth's rotation depends on its size (magnitude), location and the details of how the fault slipped.

Gross said that, in theory, anything that redistributes Earth's mass will change Earth's rotation.

"Earth's rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents," he said. "Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake. The position of Earth's figure axis also changes all the time, by about 1 meter (3.3 feet) over the course of a year, or about six times more than the change that should have been caused by the Japan quake."

Gross said that while we can measure the effects of the atmosphere and ocean on Earth's rotation, the effects of earthquakes, at least up until now, have been too small to measure. The computed change in the length of day caused by earthquakes is much smaller than the accuracy with which scientists can currently measure changes in the length of the day.

However, since the position of the figure axis can be measured to an accuracy of about 5 centimeters (2 inches), the estimated 17-centimeter shift in the figure axis from the Japan quake may actually be large enough to observe if scientists can adequately remove the larger effects of the atmosphere and ocean from the Earth rotation measurements. He and other scientists will be investigating this as more data become available.

Gross said the changes in Earth's rotation and figure axis caused by earthquakes should not have any impacts on our daily lives. "These changes in Earth's rotation are perfectly natural and happen all the time," he said. "People shouldn't worry about them."

NASA Study Goes to Earth's Core for Climate Insights

2011-03-15T05:08:00.000-07:00

The latest evidence of the dominant role humans play in changing Earth's climate comes not from observations of Earth's ocean, atmosphere or land surface, but from deep within its molten core.

Scientists have long known that the length of an Earth day - the time it takes for Earth to make one full rotation - fluctuates around a 24-hour average. Over the course of a year, the length of a day varies by about 1 millisecond, getting longer in the winter and shorter in the summer. These seasonal changes in Earth's length of day are driven by exchanges of energy between the solid Earth and fluid motions of Earth's atmosphere (blowing winds and changes in atmospheric pressure) and its ocean. Scientists can measure these small changes in Earth's rotation using astronomical observations and very precise geodetic techniques.

But the length of an Earth day also fluctuates over much longer timescales, such as interannual (two to 10 years), decadal (approximately 10 years), or those lasting multiple decades or even longer. A dominant longer timescale mode that ranges from 65 to 80 years was observed to change the length of day by approximately 4 milliseconds at the beginning of the 20th century.

These longer fluctuations are too large to be explained by the motions of Earth's atmosphere and ocean. Instead, they're due to the flow of liquid iron within Earth's outer core, where Earth's magnetic field originates. This fluid interacts with Earth's mantle to affect Earth's rotation. While scientists cannot observe these flows directly, they can deduce their movements by observing Earth's magnetic field at the surface. Previous studies have shown that this flow of liquid iron in Earth's outer core oscillates, in waves of motion that last for decades with timescales that correspond closely to long-duration variations in Earth's length of day.

Still other studies have observed a link between the long-duration variations in Earth's length of day and fluctuations of up to 0.2 degrees Celsius (0.4 degree Fahrenheit) in Earth's long-term global average surface air temperature.

So how might all three of these variables - Earth's rotation, movements in Earth's core (formally known as the core angular momentum) and global surface air temperature - be related? That's what researchers Jean Dickey and Steven Marcus of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and colleague Olivier de Viron of the Universite Paris Diderot and Institut de Physique du Globe de Paris in France, set out to discover in a first-of-its-kind study.

The scientists mapped existing data from a model of fluid movements within Earth's core and data on yearly averaged length-of-day observations against two time series of observed annual global average surface temperature: one from NASA's Goddard Institute of Space Studies in New York that extends back to 1880, and another from the United Kingdom's Met Office that extends back to 1860.

Since total air temperature is composed of two components - temperature changes that occur naturally and those caused by human activities - the researchers used results from computer climate models of Earth's atmosphere and ocean to account for temperature changes due to human activities. These human-produced temperature changes were then subtracted from the total observed temperature records to generate corrected temperature records.

The researchers found that the uncorrected temperature data correlated strongly with data on movements of Earth's core and Earth's length of day until about 1930. They then began to diverge substantially: that is, global surface air temperatures continued to increase, but without corresponding changes in Earth's length of day or movements of Earth's core. This divergence corresponds with a well-documented, robust global warming trend that has been widely attributed to increased levels of human-produced greenhouse gases.

But an examination of the corrected temperature record yielded a different result: the corrected temperature record remained strongly correlated with both Earth's length of day and movements of Earth's core throughout the entire temperature data series. The researchers performed robust tests to confirm the statistical significance of their results.

"Our research demonstrates that, for the past 160 years, decadal and longer-period changes in atmospheric temperature correspond to changes in Earth's length of day if we remove the very significant effect of atmospheric warming attributed to the buildup of greenhouse gases due to mankind's enterprise," said Dickey. "Our study implies that human influences on climate during the past 80 years mask the natural balance that exists among Earth's rotation, the core angular momentum and the temperature at Earth's surface."

So what mechanism is driving these correlations? Dickey said scientists aren't sure yet, but she offered some hypotheses.

Since scientists know air temperature can't affect movements of Earth's core or Earth's length of day to the extent observed, one possibility is the movements of Earth's core might disturb Earth's magnetic shielding of charged-particle (i.e., cosmic ray) fluxes that have been hypothesized to affect the formation of clouds. This could affect how much of the sun's energy is reflected back to space and how much is absorbed by our planet. Other possibilities are that some other core process could be having a more indirect effect on climate, or that an external (e.g. solar) process affects the core and climate simultaneously.

Regardless of the eventual connections to be established between the solid Earth and climate, Dickey said the solid Earth's impacts on climate are still dwarfed by the much larger effects of human-produced greenhouse gases. "The solid Earth plays a role, but the ultimate solution to addressing climate change remains in our hands," she concluded.

Study results were published recently in the Journal of Climate.

For more information, see: http://www.jpl.nasa.gov/news/features.cfm?feature=2420 and
http://www.jpl.nasa.gov/news/features.cfm?feature=15 .

Some of Mars' Missing Carbon Dioxide May be Buried

2011-03-11T02:03:00.000-08:00

Rocks on Mars dug from far underground by crater-blasting impacts are providing glimpses of one possible way Mars' atmosphere has become much less dense than it used to be.

At several places where cratering has exposed material from depths of about 5 kilometers (3 miles) or more beneath the surface, observations by a mineral-mapping instrument on NASA's Mars Reconnaissance Orbiter indicate carbonate minerals.

These are not the first detections of carbonates on Mars. However, compared to earlier findings, they bear closer resemblance to what some scientists have theorized for decades about the whereabouts of Mars' "missing" carbon. If deeply buried carbonate layers are found to be widespread, they would help answer questions about the disappearance of most of ancient Mars' atmosphere, which is deduced to have been thick and mostly carbon dioxide. The carbon that goes into formation of carbonate minerals can come from atmospheric carbon dioxide.

"We're looking at a pretty lucky location in terms of exposing something that was deep beneath the surface," said planetary scientist James Wray of Cornell University, Ithaca, N.Y., who reported the latest carbonate findings today at the Lunar and Planetary Science Conference near Houston. Huygens crater, a basin 467 kilometers (290 miles) in diameter in the southern highlands of Mars, had already hoisted material from far underground, and then the rim of Huygens, containing the lifted material, was drilled into by a smaller, unnamed cratering event.

Observations in the high-resolution mode of the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the Mars Reconnaissance Orbiter show spectral characteristics of calcium or iron carbonate at this site. Detections of clay minerals in lower-resolution mapping mode by CRISM had prompted closer examination with the spectrometer, and the carbonates are found near the clay minerals. Both types of minerals typically form in wet environments.

The occurrence of this type of carbonate in association with the largest impact features suggests that it was buried by a few kilometers (or miles) of younger rocks, possibly including volcanic flows and fragmented material ejected from other, nearby impacts.

These findings reinforce a report by other researchers five months ago identifying the same types of carbonate and clay minerals from CRISM observation of a site about 1,000 kilometers (600 miles) away. At that site, a meteor impact has exposed rocks from deep underground, inside Leighton crater. In their report of that discovery, Joseph Michalski of the Planetary Science Institute, Tucson, Ariz., and Paul Niles of NASA Johnson Space Center, Houston, proposed that the carbonates at Leighton "might be only a small part of a much more extensive ancient sedimentary record that has been buried by volcanic resurfacing and impact ejecta."

Carbonates found in rocks elsewhere on Mars, from orbit and by NASA's Spirit rover, are rich in magnesium. Those could form from reaction of volcanic deposits with moisture, Wray said. "The broader compositional range we're seeing that includes iron-rich and calcium-rich carbonates couldn't form as easily from just a little bit of water reacting with igneous rocks. Calcium carbonate is what you typically find on Earth's ocean and lake floors."

He said the carbonates at Huygens and Leighton "fit what would be expected from atmospheric carbon dioxide interacting with ancient bodies of water on Mars." Key additional evidence would be to find similar deposits in other regions of Mars. A hunting guide for that search is the CRISM low-resolution mapping, which has covered about three-fourths of the planet and revealed clay-mineral deposits at thousands of locations.

"A dramatic change in atmospheric density remains one of the most intriguing possibilities about early Mars," said Mars Reconnaissance Orbiter Project Scientist Richard Zurek, of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Increasing evidence for liquid water on the surface of ancient Mars for extended periods continues to suggest that the atmosphere used to be much thicker."

Carbon dioxide makes up nearly all of today's Martian air and likely was most of a thicker early atmosphere, too. In today's thin, cold atmosphere, liquid water quickly freezes or boils away.

What became of that carbon dioxide? NASA will launch the Mars Atmosphere and Volatile Evolution Mission (MAVEN) in 2013 to investigate processes that could have stripped the gas from the top of the atmosphere into interplanetary space. Meanwhile, CRISM and other instruments now in orbit continue to look for evidence that some of the carbon dioxide in that ancient atmosphere was removed, in the presence of liquid water, by formation of carbonate minerals now buried far beneath the present surface.

The Johns Hopkins University Applied Physics Laboratory, Laurel, Md., provided and operates CRISM, one of six instruments on the Mars Reconnaissance Orbiter. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter project and the Mars Exploration Program for the NASA Science Mission Directorate, Washington. For more about CRISM, see http://crism.jhuapl.edu . For more about the Mars Reconnaissance Orbiter, visit http://www.nasa.gov/mro .

NASA Finds Polar Ice Adding More to Rising Seas

2011-03-10T00:40:00.000-08:00

The Greenland and Antarctic ice sheets are losing mass at an accelerating pace, according to a new NASA-funded satellite study.

The findings of the study -- the longest to date of changes in polar ice sheet mass -- suggest these ice sheets are overtaking ice loss from Earth's mountain glaciers and ice caps to become the dominant contributor to global sea level rise, much sooner than model forecasts have predicted.

The nearly 20-year study reveals that in 2006, a year in which comparable results for mass loss in mountain glaciers and ice caps are available from a separate study conducted using other methods, the Greenland and Antarctic ice sheets lost a combined mass of 475 gigatonnes a year on average. That's enough to raise global sea level by an average of 1.3 millimeters (.05 inches) a year. (A gigatonne is one billion metric tons, or more than 2.2 trillion pounds.)

The pace at which the polar ice sheets are losing mass was found to be accelerating rapidly. Each year over the course of the study, the two ice sheets lost a combined average of 36.3 gigatonnes more than they did the year before. In comparison, the 2006 study of mountain glaciers and ice caps estimated their loss at 402 gigatonnes a year on average, with a year-over-year acceleration rate three times smaller than that of the ice sheets.

"That ice sheets will dominate future sea level rise is not surprising -- they hold a lot more ice mass than mountain glaciers," said lead author Eric Rignot, jointly of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of California, Irvine.

"What is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007. Our study helps reduce uncertainties in near-term projections of sea level rise."

Rignot's team combined nearly two decades (1992-2009) of monthly satellite measurements with advanced regional atmospheric climate model data to examine changes in ice sheet mass and trends in acceleration of ice loss.

The study compared two independent measurement techniques. The first characterized the difference between two sets of data: interferometric synthetic aperture radar data from European, Canadian and Japanese satellites and radio echo soundings, which were used to measure ice exiting the ice sheets; and regional atmospheric climate model data from Utrecht University, The Netherlands, used to quantify ice being added to the ice sheets. The other technique used eight years of data from the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (Grace) satellites, which track minute changes in Earth's gravity field due to changes in Earth's mass distribution, including ice movement.

The team reconciled the differences between techniques and found them to be in agreement, both for total amount and rate of mass loss, over their data sets' eight-year overlapping period. This validated the data sets, establishing a consistent record of ice mass changes since 1992.

The team found that for each year over the 18-year study, the Greenland ice sheet lost mass faster than it did the year before, by an average of 21.9 gigatonnes a year. In Antarctica, the year-over-year speedup in ice mass lost averaged 14.5 gigatonnes.

"These are two totally independent techniques, so it is a major achievement that the results agree so well," said co-author Isabella Velicogna, also jointly with JPL and UC Irvine. "It demonstrates the tremendous progress that's being made in estimating how much ice the ice sheets are gaining and losing, and in analyzing Grace's time-variable gravity data."

The authors conclude that, if current ice sheet melting rates continue for the next four decades, their cumulative loss could raise sea level by 15 centimeters (5.9 inches) by 2050. When this is added to the predicted sea level contribution of 8 centimeters (3.1 inches) from glacial ice caps and 9 centimeters (3.5 inches) from ocean thermal expansion, total sea level rise could reach 32 centimeters (12.6 inches). While this provides one indication of the potential contribution ice sheets could make to sea level in the coming century, the authors caution that considerable uncertainties remain in estimating future ice loss acceleration.

Study results are published this month in Geophysical Research Letters. Other participating institutions include the Institute for Marine and Atmospheric Research, Utrecht University, The Netherlands; and the National Center for Atmospheric Research, Boulder, Colo.

JPL developed Grace and manages the mission for NASA. The University of Texas Center for Space Research in Austin has overall mission responsibility. GeoForschungsZentrum Potsdam (GFZ), Potsdam, Germany, is responsible for German mission elements.

More on Grace is online at http://www.csr.utexas.edu/grace/ and http://grace.jpl.nasa.gov/ .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

NASA's Jupiter-Bound Spacecraft Taking Shape In Denver

2011-03-09T02:22:00.000-08:00

NASA's Juno spacecraft is currently undergoing environmental testing at Lockheed Martin Space Systems near Denver.

The solar-powered Juno spacecraft will orbit Jupiter's poles 33 times to find out more about the gas giant's origins, structure, atmosphere and magnetosphere. The launch window for Juno from the Cape Canaveral Air Force Station in Florida opens Aug. 5, 2011.

In its present form, the spacecraft is fully assembled and all instruments have been integrated. A photograph of the fully assembled spacecraft is available at: http://www.nasa.gov/mission_pages/juno/multimedia/juno20110307i.html

In this photo, taken on Jan. 26, Juno had just completed acoustics testing that simulated the acoustic and vibration environment the spacecraft will experience during launch. The photo shows Lockheed Martin technicians inspecting the spacecraft just after the test. All three solar array wings are installed and stowed, and the spacecraft's large high-gain antenna is in place on the top of the avionics vault.

At present, Juno is sealed in a large thermal vacuum chamber, where it is being exposed to the extreme cold and vacuum conditions it will experience on its voyage to Jupiter. The two-week-long test will simulate many of the flight activities the spacecraft will execute during the mission.

Juno is scheduled to ship from Lockheed Martin's facility to Kennedy Space Center in early April, where it will undergo final preparations and launch.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute at San Antonio, Texas. Lockheed Martin Space Systems, Denver, is building the spacecraft. The Italian Space Agency in Rome is contributing an infrared spectrometer instrument and a portion of the radio science experiment. JPL is a division of the California Institute of Technology in Pasadena.

Double Vision: NASA Earth Satellites Prep for Launch

2011-03-07T01:55:00.000-08:00

In a rare event, two NASA launch vehicles currently rise above California's Vandenberg Air Force Base, as NASA's two, new Earth monitoring satellites, Glory and Aquarius, ready for their respective launches.

Both the Glory spacecraft and Taurus XL rocket are ready for launch Friday, March 4, at 2:09:43 a.m. PST (5:09:43 a.m. EST). The weather forecast is 100 percent "go," with the possibility of some fog and a low ceiling not expected to be an issue.

The liftoff from Vandenberg Air Force Base (Launch Complex 576-E) is targeted for the middle of a 48-second launch window. Spacecraft separation will occur 13 minutes after launch.

Technical issues with ground support equipment for the Taurus XL launch vehicle led to the scrub of the first launch attempt on Feb. 23.

Data from the Glory mission will allow scientists to better understand how the sun and tiny atmospheric particles called aerosols affect Earth's climate. Both aerosols and solar energy influence the planet's energy budget -- the amount of energy entering and exiting Earth's atmosphere.

Meanwhile, nearby, the first stage of the Delta II rocket that will carry NASA's Aquarius instrument into low Earth orbit has been raised onto its launch pad at Vandenberg Air Force Base's Space Launch Complex-2 (SLC-2).

Scheduled to launch in June, Aquarius' mission will provide monthly maps of global changes in sea surface salinity. By measuring ocean salinity from space, Aquarius will provide new insights into how the massive natural interplay of freshwater among the ocean, atmosphere and sea ice influences ocean circulation, weather and climate.

Aquarius will launch on the Satélite de Aplicaciones Científicas (SAC)-D spacecraft, built by Argentina's Comision Nacional de Actividades Espaciales (CONAE). The SAC-D spacecraft and its Aquarius instrument are scheduled to be shipped from South America to the launch site in late March. The Aquarius instrument was built jointly by NASA's Jet Propulsion Laboratory, Pasadena, Calif., and NASA's Goddard Space Flight Center, Greenbelt, Md.

Advanced NASA Instrument Gets Close-up on Mars Rocks

2011-03-05T00:43:00.000-08:00

NASA's Mars Science Laboratory rover, Curiosity, will carry a next generation, onboard "chemical element reader" to measure the chemical ingredients in Martian rocks and soil.

The instrument is one of 10 that will help the rover in its upcoming mission to determine the past and present habitability of a specific area on the Red Planet. Launch is scheduled between Nov. 25 and Dec. 18, 2011, with landing in August 2012.

The Alpha Particle X-Ray Spectrometer (APXS) instrument, designed by physics professor Ralf Gellert of the University of Guelph in Ontario, Canada, uses the power of alpha particles, or helium nuclei, and X-rays to bombard a target, causing the target to give off its own characteristic alpha particles and X-ray radiation. This radiation is "read by" an X-ray detector inside the sensor head, which reveals which elements and how much of each are in the rock or soil.

Identifying the elemental composition of lighter elements such as sodium, magnesium or aluminum, as well as heavier elements like iron, nickel or zinc, will help scientists identify the building blocks of the Martian crust. By comparing these findings with those of previous Mars rover findings, scientists can determine if any weathering has taken place since the rock formed ages ago.

All NASA Mars rovers have carried a similar instrument – Pathfinder's rover Sojourner, Spirit and Opportunity, and now Curiosity, too. Improvements have been made with each generation, but the basic design of the instrument has remained the same.

"APXS was modified for Mars Science Laboratory to be faster so it could make quicker measurements. On the Mars Exploration Rovers [Spirit and Opportunity] it took us five to 10 hours to get information that we will now collect in two to three hours," said Gellert, the instrument's principal investigator. "We hope this will help us to investigate more samples."

Another significant change to the next-generation APXS is the cooling system on the X-ray detector chip. The instruments used on Spirit and Opportunity were able to take measurements only at night. But the new cooling system will allow the instrument on Curiosity to take measurements during the day, too.

The main electronics portion of the tissue-box-sized instrument lives in the rover's body, while the sensor head, the size of a soft drink can, is mounted on the robotic arm. With the help of Curiosity's remote sensing instruments – the Chemistry and Camera (ChemCam) instrument and the Mastcam – the rover team will decide where to drive Curiosity for a closer look with the instruments, including APXS. Measurements are taken with the APXS by deploying the sensor head to make direct contact with the desired sample.

The rover's brush will be used to remove dust from rocks to prepare them for inspection by APXS and by MAHLI, the rover's arm-mounted, close-up camera. Whenever promising samples are found, the rover will then use its drill to extract a few grains and feed them into the rover's analytical instruments, SAM and CheMin, which will then make very detailed mineralogical and other investigations.

Scientists will use information from APXS and the other instruments to find the interesting spots and to figure out the present and past environmental conditions that are preserved in the rocks and soils.

"The rovers have answered a lot of questions, but they've also opened up new questions," said Gellert. "Curiosity was designed to pick up where Spirit and Opportunity left off."

For more information about the mission, visit http://mars.jpl.nasa.gov/msl/ . To watch the spacecraft being assembled and tested, visit http://www.ustream.tv/nasajpl .

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory mission for the NASA Science Mission Directorate, Washington.

The MSL APXS is funded by the Canadian Space Agency, with MDA Corporation as prime subcontractor to build the instrument. Funding for the science team comes from CSA, NASA, and the University of Guelph.

NASA Earth Satellites Prep for Launch

2011-03-04T06:18:00.000-08:00

Herschel Measures Dark Matter for Star-Forming Galaxies

2011-03-02T04:46:00.000-08:00

The Herschel Space Observatory has revealed how much dark matter it takes to form a new galaxy bursting with stars. Herschel is a European Space Agency cornerstone mission supported with important NASA contributions.

The findings are a key step in understanding how dark matter, an invisible substance permeating our universe, contributed to the birth of massive galaxies in the early universe.

"If you start with too little dark matter, then a developing galaxy would peter out," said astronomer Asantha Cooray of the University of California, Irvine. He is the principal investigator of new research appearing in the journal Nature, online on Feb. 16 and in the Feb. 24 print edition. "If you have too much, then gas doesn't cool efficiently to form one large galaxy, and you end up with lots of smaller galaxies. But if you have the just the right amount of dark matter, then a galaxy bursting with stars will pop out."

The right amount of dark matter turns out to be a mass equivalent to 300 billion of our suns.

Herschel launched into space in May 2009. The mission's large, 3.5-meter (11.5-foot) telescope detects longer-wavelength infrared light from a host of objects, ranging from asteroids and planets in our own solar system to faraway galaxies.

"This remarkable discovery shows that early galaxies go through periods of star formation much more vigorous than in our present-day Milky Way," said William Danchi, Herschel program scientist at NASA Headquarters in Washington. "It showcases the importance of infrared astronomy, enabling us to peer behind veils of interstellar dust to see stars in their infancy."

Cooray and colleagues used the telescope to measure infrared light from massive, star-forming galaxies located 10 to 11 billion light-years away. Astronomers think these and other galaxies formed inside clumps of dark matter, similar to chicks incubating in eggs.

Giant clumps of dark matter act like gravitational wells that collect the gas and dust needed for making galaxies. When a mixture of gas and dust falls into a well, it condenses and cools, allowing new stars to form. Eventually enough stars form, and a galaxy is born.

Herschel was able to uncover more about how this galaxy-making process works by mapping the infrared light from collections of very distant, massive star-forming galaxies. This pattern of light, called the cosmic infrared background, is like a web that spreads across the sky. Because Herschel can survey large areas quickly with high resolution, it was able to create the first detailed maps of the cosmic infrared background.

"It turns out that it's much more effective to look at these patterns rather than the individual galaxies," said Jamie Bock of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Bock is the U.S. principal investigator for Herschel's Spectral and Photometric Imaging Receiver instrument used to make the maps. "This is like looking at a picture in a magazine from a reading distance. You don't notice the individual dots, but you see the big picture. Herschel gives us the big picture of these distant galaxies, showing the influence of dark matter."

The maps showed the galaxies are more clustered into groups than previously believed. The amount of galaxy clustering depends on the amount of dark matter. After a series of complicated numerical simulations, the astronomers were able to determine exactly how much dark matter is needed to form a single star-forming galaxy.

"This measurement is important, because we are homing in on the very basic ingredients in galaxy formation," said Alexandre Amblard of UC Irvine, first author of the Nature paper. "In this case, the ingredient, dark matter, happens to be an exotic substance that we still have much to learn about."

NASA's Herschel Project Office is based at JPL, which contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. JPL is managed by Caltech.

More information is online at http://www.herschel.caltech.edu, http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel/index.html .

NASA Probe Sees Solar Wind Decline

2011-03-01T03:47:00.000-08:00

The 33-year odyssey of NASA's Voyager 1 spacecraft has reached a distant point at the edge of our solar system where there is no outward motion of solar wind.

Now hurtling toward interstellar space some 17.4 billion kilometers (10.8 billion miles) from the sun, Voyager 1 has crossed into an area where the velocity of the hot ionized gas, or plasma, emanating directly outward from the sun has slowed to zero. Scientists suspect the solar wind has been turned sideways by the pressure from the interstellar wind in the region between stars.

The event is a major milestone in Voyager 1's passage through the heliosheath, the turbulent outer shell of the sun's sphere of influence, and the spacecraft's upcoming departure from our solar system.

"The solar wind has turned the corner," said Ed Stone, Voyager project scientist based at the California Institute of Technology in Pasadena, Calif. "Voyager 1 is getting close to interstellar space."

Our sun gives off a stream of charged particles that form a bubble known as the heliosphere around our solar system. The solar wind travels at supersonic speed until it crosses a shockwave called the termination shock. At this point, the solar wind dramatically slows down and heats up in the heliosheath.

Launched on Sept. 5, 1977, Voyager 1 crossed the termination shock in December 2004 into the heliosheath. Scientists have used data from Voyager 1's Low-Energy Charged Particle Instrument to deduce the solar wind's velocity. When the speed of the charged particles hitting the outward face of Voyager 1 matched the spacecraft's speed, researchers knew that the net outward speed of the solar wind was zero. This occurred in June, when Voyager 1 was about 17 billion kilometers (10.6 billion miles) from the sun.

Because the velocities can fluctuate, scientists watched four more monthly readings before they were convinced the solar wind's outward speed actually had slowed to zero. Analysis of the data shows the velocity of the solar wind has steadily slowed at a rate of about 20 kilometers per second each year (45,000 mph each year) since August 2007, when the solar wind was speeding outward at about 60 kilometers per second (130,000 mph). The outward speed has remained at zero since June.

The results were presented today at the American Geophysical Union meeting in San Francisco.

"When I realized that we were getting solid zeroes, I was amazed," said Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator and senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Here was Voyager, a spacecraft that has been a workhorse for 33 years, showing us something completely new again."

Scientists believe Voyager 1 has not crossed the heliosheath into interstellar space. Crossing into interstellar space would mean a sudden drop in the density of hot particles and an increase in the density of cold particles. Scientists are putting the data into their models of the heliosphere's structure and should be able to better estimate when Voyager 1 will reach interstellar space. Researchers currently estimate Voyager 1 will cross that frontier in about four years.

"In science, there is nothing like a reality check to shake things up, and Voyager 1 provided that with hard facts," said Tom Krimigis, principal investigator on the Low-Energy Charged Particle Instrument, who is based at the Applied Physics Laboratory and the Academy of Athens, Greece. "Once again, we face the predicament of redoing our models."

A sister spacecraft, Voyager 2, was launched in Aug. 20, 1977 and has reached a position 14.2 billion kilometers (8.8 billion miles) from the sun. Both spacecraft have been traveling along different trajectories and at different speeds. Voyager 1 is traveling faster, at a speed of about 17 kilometers per second (38,000 mph), compared to Voyager 2's velocity of 15 kilometers per second (35,000 mph). In the next few years, scientists expect Voyager 2 to encounter the same kind of phenomenon as Voyager 1.

The Voyagers were built by NASA's Jet Propulsion Laboratory in Pasadena, Calif., which continues to operate both spacecraft. For more information about the Voyager spacecraft, visit: http://www.nasa.gov/voyager . JPL is a division of the California Institute of Technology in Pasadena.

Cassini to Sample Magnetic Environment around Titan

2011-02-28T01:31:00.000-08:00

NASA's Cassini spacecraft is set to skim close to Saturn's moon Titan on Friday, Feb. 18, to learn about the interaction between Titan and Saturn's magnetosphere, the magnetic bubble around the planet.

The closest approach will take place at 8:04 a.m. PST (4:04 p.m. UTC) and bring Cassini within about 3,650 kilometers (2,270 miles) of Titan's surface.

As Titan makes a complete 360-degree orbit around Saturn, the relative influence of the sun's illumination and the hot ionized gas trapped in the magnetic bubble changes. These factors are important for understanding the relationship between Titan and Saturn's magnetosphere. It is important to make measurements at a variety of locations in the Saturn magnetosphere, so this flyby will occur in a part of the magnetosphere that has been poorly sampled so far.

Previous flybys have shown the magnetic environment near Titan to be rather variable and unpredictable. For 12 hours before and after closest approach, the Cassini plasma spectrometer instrument will be pointing in a direction to capture ionized gas in the region.

At the same time, Cassini's radio science subsystem will be gathering sensitive gravity data from Titan to improve understanding of the structure of the interior. Collecting data like these will eventually enable scientists to determine whether Titan has an ocean under its crust.

Other instruments will also be collecting data, much of it pertaining to seasonal change. Titan is currently in northern spring, approaching northern summer, and scientists want to know what has changed with the north polar winter vortex weather pattern. The composite infrared spectrometer, for instance, will be mapping temperatures in Titan's stratosphere. The imaging science subsystem will also be monitoring the lakes, clouds and transport of aerosols in the Titan atmosphere.

This latest flyby is dubbed "T74," though planning changes early in the orbital tour have made this the 75th targeted flyby of Titan.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

More information about the flyby is available at:
http://saturn.jpl.nasa.gov/mission/flybys/titan20110218/

More information about the Cassini-Huygens mission is at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

Upcoming changes to the NASA Technical Reports Server

2011-02-24T00:35:00.000-08:00

The NASA Technical Reports Server (NTRS) provides world-wide access to publicly available NASA scientific and technical information.

On March 1, 2011 the NTRS will debut an updated interface and new capabilities. The updated interface will feature a simple full-text search as well as advanced searching capabilities. New features include the ability to download citations, as well as share citations via social networking tools.

Also note that there will be some changes to the NTRS OAI Harvesting Service. For details see: http://ntrs.nasa.gov/index.jsp?method=harvest.

If you have any questions or comments, please contact the CASI Information Desk via email or phone at 443-757-5802.

Need additional help searching for particular documents or a certain topic? Members of the Glenn community can contact the Library at 3-5781 or 3-5762 for additional assistance.

Hot Water: The Oceans and Global Warming

2011-02-23T01:32:00.000-08:00

Water covers nearly 70 percent of its surface, so it's no wonder that the world's oceans play such an important role in global climate changes. As the planet heats up, the oceans wind up being by far the biggest reservoir for taking up the extra heat. This talk will cover the ins and outs of global warming as they pertain to the world ocean.

Can WISE Find the Hypothetical 'Tyche'?

2011-02-22T01:20:00.000-08:00

In November 2010, the scientific journal Icarus published a paper by astrophysicists John Matese and Daniel Whitmire, who proposed the existence of a binary companion to our sun, larger than Jupiter, in the long-hypothesized "Oort cloud" -- a faraway repository of small icy bodies at the edge of our solar system.

The researchers use the name "Tyche" for the hypothetical planet. Their paper argues that evidence for the planet would have been recorded by the Wide-field Infrared Survey Explorer (WISE).

WISE is a NASA mission, launched in December 2009, which scanned the entire celestial sky at four infrared wavelengths about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets relatively close to Earth. Recently, WISE completed an extended mission, allowing it to finish a complete scan of the asteroid belt, and two complete scans of the more distant universe, in two infrared bands.

So far, the mission's discoveries of previously unknown objects include an ultra-cold star or brown dwarf, 20 comets, 134 near-Earth objects (NEOs), and more than 33,000 asteroids in the main belt between Mars and Jupiter.

Following its successful survey, WISE was put into hibernation in February 2011. Analysis of WISE data continues. A preliminary public release of the first 14 weeks of data is planned for April 2011, and the final release of the full survey is planned for March 2012.

Frequently Asked Questions

Q: When could data from WISE confirm or rule out the existence of the hypothesized planet Tyche?

A: It is too early to know whether WISE data confirms or rules out a large object in the Oort cloud. Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not. The first 14 weeks of data, being released in April 2011, are unlikely to be sufficient. The full survey, scheduled for release in March 2012, should provide greater insight. Once the WISE data are fully processed, released and analyzed, the Tyche hypothesis that Matese and Whitmire propose will be tested.

Q: Is it a certainty that WISE would have observed such a planet if it exists?

A: It is likely but not a foregone conclusion that WISE could confirm whether or not Tyche exists. Since WISE surveyed the whole sky once, then covered the entire sky again in two of its infrared bands six months later, WISE would see a change in the apparent position of a large planet body in the Oort cloud over the six-month period. The two bands used in the second sky coverage were designed to identify very small, cold stars (or brown dwarfs) -- which are much like planets larger than Jupiter, as Tyche is hypothesized to be.

Q: If Tyche does exist, why would it have taken so long to find another planet in our solar system?

A: Tyche would be too cold and faint for a visible light telescope to identify. Sensitive infrared telescopes could pick up the glow from such an object, if they looked in the right direction. WISE is a sensitive infrared telescope that looks in all directions.

Q: Why is the hypothesized object dubbed "Tyche," and why choose a Greek name when the names of other planets derive from Roman mythology?

A: In the 1980s, a different companion to the sun was hypothesized. That object, named for the Greek goddess "Nemesis," was proposed to explain periodic mass extinctions on the Earth. Nemesis would have followed a highly elliptical orbit, perturbing comets in the Oort Cloud roughly every 26 million years and sending a shower of comets toward the inner solar system. Some of these comets would have slammed into Earth, causing catastrophic results to life.

Recent scientific analysis no longer supports the idea that extinctions on Earth happen at regular, repeating intervals. Thus, the Nemesis hypothesis is no longer needed. However, it is still possible that the sun could have a distant, unseen companion in a more circular orbit with a period of a few million years -- one that would not cause devastating effects to terrestrial life. To distinguish this object fr
om the malevolent "Nemesis," astronomers chose the name of Nemesis's benevolent sister in Greek mythology, "Tyche."

JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md.

The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise, http://wise.astro.ucla.edu and http://www.jpl.nasa.gov/wise .

Advanced NASA Instrument Gets Close-up on Mars Rocks

2011-02-21T01:33:00.000-08:00

NASA's Mars Science Laboratory rover, Curiosity, will carry a next generation, onboard "chemical element reader" to measure the chemical ingredients in Martian rocks and soil.

The instrument is one of 10 that will help the rover in its upcoming mission to determine the past and present habitability of a specific area on the Red Planet. Launch is scheduled between Nov. 25 and Dec. 18, 2011, with landing in August 2012.

The Alpha Particle X-Ray Spectrometer (APXS) instrument, designed by physics professor Ralf Gellert of the University of Guelph in Ontario, Canada, uses the power of alpha particles, or helium nuclei, and X-rays to bombard a target, causing the target to give off its own characteristic alpha particles and X-ray radiation. This radiation is "read by" an X-ray detector inside the sensor head, which reveals which elements and how much of each are in the rock or soil.

Identifying the elemental composition of lighter elements such as sodium, magnesium or aluminum, as well as heavier elements like iron, nickel or zinc, will help scientists identify the building blocks of the Martian crust. By comparing these findings with those of previous Mars rover findings, scientists can determine if any weathering has taken place since the rock formed ages ago.

All NASA Mars rovers have carried a similar instrument – Pathfinder's rover Sojourner, Spirit and Opportunity, and now Curiosity, too. Improvements have been made with each generation, but the basic design of the instrument has remained the same.

"APXS was modified for Mars Science Laboratory to be faster so it could make quicker measurements. On the Mars Exploration Rovers [Spirit and Opportunity] it took us five to 10 hours to get information that we will now collect in two to three hours," said Gellert, the instrument's principal investigator. "We hope this will help us to investigate more samples."

Another significant change to the next-generation APXS is the cooling system on the X-ray detector chip. The instruments used on Spirit and Opportunity were able to take measurements only at night. But the new cooling system will allow the instrument on Curiosity to take measurements during the day, too.

The main electronics portion of the tissue-box-sized instrument lives in the rover's body, while the sensor head, the size of a soft drink can, is mounted on the robotic arm. With the help of Curiosity's remote sensing instruments – the Chemistry and Camera (ChemCam) instrument and the Mastcam – the rover team will decide where to drive Curiosity for a closer look with the instruments, including APXS. Measurements are taken with the APXS by deploying the sensor head to make direct contact with the desired sample.

The rover's brush will be used to remove dust from rocks to prepare them for inspection by APXS and by MAHLI, the rover's arm-mounted, close-up camera. Whenever promising samples are found, the rover will then use its drill to extract a few grains and feed them into the rover's analytical instruments, SAM and CheMin, which will then make very detailed mineralogical and other investigations.

Scientists will use information from APXS and the other instruments to find the interesting spots and to figure out the present and past environmental conditions that are preserved in the rocks and soils.

"The rovers have answered a lot of questions, but they've also opened up new questions," said Gellert. "Curiosity was designed to pick up where Spirit and Opportunity left off."

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory mission for the NASA Science Mission Directorate, Washington.

For more information about the mission, visit http://mars.jpl.nasa.gov/msl/ . To watch the spacecraft being assembled and tested, visit http://www.ustream.tv/nasajpl .

NASA Releases Images of Man-Made Crater on Comet

2011-02-20T22:09:00.000-08:00

NASA's Stardust spacecraft returned new images of a comet showing a scar resulting from the 2005 Deep Impact mission. The images also showed the comet has a fragile and weak nucleus.

The spacecraft made its closest approach to comet Tempel 1 on Monday, Feb. 14, at 8:40 p.m. PST (11:40 p.m. EST) at a distance of approximately 178 kilometers (111 miles). Stardust took 72 high-resolution images of the comet. It also accumulated 468 kilobytes of data about the dust in its coma, the cloud that is a comet's atmosphere. The craft is on its second mission of exploration called Stardust-NExT, having completed its prime mission collecting cometary particles and returning them to Earth in 2006.

The Stardust-NExT mission met its goals, which included observing surface features that changed in areas previously seen during the 2005 Deep Impact mission; imaging new terrain; and viewing the crater generated when the 2005 mission propelled an impactor at the comet.

"This mission is 100 percent successful," said Joe Veverka, Stardust-NExT principal investigator of Cornell University, Ithaca, N.Y. "We saw a lot of new things that we didn't expect, and we'll be working hard to figure out what Tempel 1 is trying to tell us."

Several of the images provide tantalizing clues to the result of the Deep Impact mission's collision with Tempel 1.

"We see a crater with a small mound in the center, and it appears that some of the ejecta went up and came right back down," said Pete Schultz of Brown University, Providence, R.I. "This tells us this cometary nucleus is fragile and weak based on how subdued the crater is we see today."

Engineering telemetry downlinked after closest approach indicates the spacecraft flew through waves of disintegrating cometary particles, including a dozen impacts that penetrated more than one layer of its protective shielding.

"The data indicate Stardust went through something similar to a B-17 bomber flying through flak in World War II," said Don Brownlee, Stardust-NExT co-investigator from the University of Washington in Seattle. "Instead of having a little stream of uniform particles coming out, they apparently came out in chunks and crumbled."

While the Valentine's Day night encounter of Tempel 1 is complete, the spacecraft will continue to look at its latest cometary obsession from afar.

"This spacecraft has logged over 3.5 billion miles since launch, and while its last close encounter is complete, its mission of discovery is not," said Tim Larson, Stardust-NExT project manager at JPL. "We'll continue imaging the comet as long as the science team can gain useful information, and then Stardust will get its well-deserved rest."

Stardust-NExT is a low-cost mission that is expanding the investigation of comet Tempel 1 initiated by the Deep Impact spacecraft. The mission is managed by JPL for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft and manages day-to-day mission operations.

The latest Stardust-Next/Tempel 1 images are online at: http://www.nasa.gov/mission_pages/stardust/multimedia/gallery-index.html

Comet Hunter's First Images on the Ground

2011-02-18T00:38:00.000-08:00

Mission controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., have begun receiving the first of 72 anticipated images of comet Tempel 1 taken by NASA's Stardust spacecraft.

The first six, most distant approach images are available at http://www.nasa.gov/stardust and http://www.jpl.nasa.gov. Additional images, including those from closest approach, are being downlinked in chronological order and will be available later in the day.

A news conference will be held at 12:30 p.m. PST (3:30 p.m. EST) to allow scientists more time to analyze the data and images.

Stardust-NExT is a low-cost mission that expands on the investigation of comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of Technology in Pasadena, manages Stardust-NExT for NASA's Science Mission Directorate, Washington, D.C. Joe Veverka of Cornell University, Ithaca, N.Y., is the mission's principal investigator. Lockheed Martin Space Systems, Denver, built the spacecraft and manages day-to-day mission operations.

New View of Family Life in the North American Nebula

2011-02-16T00:37:00.000-08:00

Stars at all stages of development, from dusty little tots to young adults, are on display in a new image from NASA's Spitzer Space Telescope.

This cosmic community is called the North American nebula. In visible light, the region resembles the North American continent, with the most striking resemblance being the Gulf of Mexico. But in Spitzer's infrared view, the continent disappears. Instead, a swirling landscape of dust and young stars comes into view.

"One of the things that makes me so excited about this image is how different it is from the visible image, and how much more we can see in the infrared than in the visible," said Luisa Rebull of NASA's Spitzer Science Center at the California Institute of Technology, Pasadena, Calif. Rebull is lead author of a paper about the observations, accepted for publication in the Astrophysical Journal Supplement Series. "The Spitzer image reveals a wealth of detail about the dust and the young stars here."

The new image is online at http://www.nasa.gov/mission_pages/spitzer/multimedia/pia13844.html .

Rebull and her team have identified more than 2,000 new, candidate young stars in the region. There were only about 200 known before. Because young stars grow up surrounded by blankets of dust, they are hidden in visible-light images. Spitzer's infrared detectors pick up the glow of the dusty, buried stars.

A star is born inside a collapsing ball of gas and dust. As the material collapses inward, it flattens out into a disk that spins around together with the forming star like a spinning top. Jets of gas shoot perpendicularly away from the disk, above and below it. As the star ages, planets are thought to form out of the disk -- material clumps together, ultimately growing into mature planets. Eventually, most of the dust dissipates, aside from a tenuous ring similar to the one in our solar system, referred to as Zodiacal dust.

The new Spitzer image reveals all the stages of a star's young life, from the early years when it is swaddled in dust to early adulthood, when it has become a young parent to a family of developing planets. Sprightly "toddler" stars with jets can also be identified in Spitzer's view.

"This is a really busy area to image, with stars everywhere, from the North American complex itself, as well as in front of and behind the region," said Rebull. "We refer to the stars that are not associated with the region as contamination. With Spitzer, we can easily sort this contamination out and clearly distinguish between the young stars in the complex and the older ones that are unrelated."

The North American nebula still has a mystery surrounding it, involving its power source. Nobody has been able to identify the group of massive stars that is thought to be dominating the nebula. The Spitzer image, like images from other telescopes, hints that the missing stars are lurking behind the Gulf of Mexico portion of the nebula. This is evident from the illumination pattern of the nebula, especially when viewed with the detector on Spitzer that picks up 24-micron infrared light. That light appears to be coming from behind the Gulf of Mexico's dark tangle of clouds, in the same way that sunlight creeps out from behind a rain cloud.

The nebula's distance from Earth is also a mystery. Current estimates put it at about 1,800 light-years from Earth. Spitzer will refine this number by finding more stellar members of the North American complex.

The Spitzer observations were made before it ran out of the liquid coolant needed to chill its longer-wavelength instruments. Currently, Spitzer's two shortest-wavelength channels (3.6 and 4.5 microns) are still working. The composite image shows light from both the infrared array camera and multiband imaging processor. Infrared light with a wavelength of 3.6 microns is color-coded blue; 8.0-micron light is green; and 24-micron light is red.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

NASA's Stardust Spacecraft Completes Comet Flyby

2011-02-15T00:38:00.000-08:00

Mission controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., watched as data downlinked from the Stardust spacecraft indicated it completed its closest approach with comet Tempel 1.

An hour after closest approach, the spacecraft turned to point its large, high-gain antenna at Earth. It is expected that images of the comet's nucleus collected during the flyby will be received on Earth starting at about midnight California time (3 a.m. EST on Tuesday, Feb. 15).

Preliminary data already transmitted from the spacecraft indicate the time of closest approach was about 8:39 p.m. PST (11:39 p.m. EST), at a distance of 181 kilometers (112 miles) from Tempel 1.

This is a bonus mission for the comet chaser, which previously flew past comet Wild 2 and returned samples from its coma to Earth. During this bonus encounter, the plan called for the spacecraft to take images of the comet's surface to observe what changes occurred since a NASA spacecraft last visited. (NASA's Deep Impact spacecraft executed an encounter with Tempel 1 in July 2005).

Stardust-NExT is a low-cost mission that will expand the investigation of comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of Technology in Pasadena, manages Stardust-NExT for NASA's Science Mission Directorate, Washington, D.C. Lockheed Martin Space Systems, Denver, built the spacecraft and manages day-to-day mission operations.

Heading Into the Bonus Round -- in Space

2011-02-14T00:35:00.000-08:00

A bonus round is something one usually associates with the likes of a TV game show, not a pioneering deep space mission.

"We are definitely in the bonus round," said Stardust-NExT Project Manager Tim Larson of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This spacecraft has already flown by an asteroid and a comet, returned comet dust samples to Earth, and now has almost doubled its originally planned mission life. Now it is poised to perform one more comet flyby."

A Successful Prime Mission

NASA's Stardust spacecraft was launched on Feb. 7, 1999, on a mission that would explore a comet as no previous mission had. Before Stardust, seven spacecraft from NASA, Russia, Japan and the European Space Agency had visited comets – they had flight profiles that allowed them to perform brief encounters, collecting data and sometimes images of the nuclei during the flyby.

Like those comet hunters before it, Stardust was tasked to pass closely by a comet, collecting data and snapping images. It also had the ability to come home again, carrying with it an out-of -this-world gift for cometary scientists – particles of the comet itself. Along the way, the telephone booth-sized comet hunter racked up numerous milestones and more than a few "space firsts."

In the first round of its prime mission, Stardust performed observations of asteroid Annefrank, only the sixth asteroid in history to be imaged close up. After that, Stardust racked up more points of space exploration firsts. It became the first spacecraft to capture particles of interstellar dust for Earth return. It was first to fly past a comet and collect data and particles of comet dust (hurtling past it at almost four miles per second) for later analysis. Then, it was first to make the trip back to Earth after traveling beyond the orbit of Mars (a two-year trip of 1.2 billion kilometers, or 752 million miles). When Stardust dropped off its sample return capsule from comet Wild 2, the capsule became the fastest human-made object to enter Earth's atmosphere. The mission was also the first to provide a capsule containing cometary dust specimens, speciments that will have scientists uncovering secrets of comets for years to come.

With such a high tally of "firsts" on its scoreboard, you'd think Stardust could receive a few parting gifts and leave the game. And an important part of the original spacecraft is currently enjoying retirement – albeit a high-profile one: Stardust's 100-pound sample return capsule is on display in the main hall (Milestones of Flight) of the Smithsonian's National Air and Space Museum in Washington. But the rest of NASA's most-seasoned comet hunter is still up there – and there is work still to be done.

"We placed Stardust in a parking orbit that would carry it back by Earth in a couple of years, and then asked the science community for proposals on what could be done with a spacecraft that had a lot of zeros on its odometer, but also had some fuel and good miles left in it," said Jim Green, director of NASA's Planetary Science Division.

Moving into the Bonus Round

In January 2007, from a stack of proposals with intriguing ideas, NASA chose Stardust-NExT (Stardust's Next Exploration of Tempel). It was a plan to revisit comet Tempel 1 at a tenth of the cost of a new, from-the-ground-up mission. Comet Tempel 1 was of particular interest to NASA. It had been the target of a previous NASA spacecraft visit in July 2005. That mission, Deep Impact, placed a copper-infused, 800-pound impactor on a collision course with the comet and observed the results from the cosmic fender-bender via the telescopic cameras onboard the larger part of Deep Impact, a "flyby" spacecraft observing from a safe distance.

"The plan for our encounter is to be more hospitable to comet Tempel 1 than our predecessor," said Joe Veverka, principal investigator of Stardust-NExT from Cornell University in Ithaca, N.Y. "We will come within about 200 kilometers [124 miles] of Tempel 1 and view the changes that took place over the past five-and-a-half years."

That period of time is significant for Tempel 1 -- it is the period of time it takes the comet to orbit the sun once. Not much happens during a comet's transit through the chilly reaches of the outer solar system. But when it nears perihelion (the point in its orbit that an object, such as a planet or a comet, is closest to the sun), things begin to sizzle.

"Comets can be very spectacular when they come close to the sun, but we still don't understand them as well as we should," said Veverka. "They are also messengers from the past. They tell us how the solar system was formed long ago, and Stardust-NExT will help us understand how much they have changed since their formation."

So the spacecraft that had traveled farther afield than any of its predecessors was being sent out again in the name of scientific opportunity. In between spacecraft and comet lay four-and-a-half years, over a billion kilometers (646 million miles), and more than a few hurdles along the way.

Your Mileage May Vary

"One of the challenges with reusing a spacecraft designed for a different prime mission is you don't get to start out with a full tank of gas," said Larson. "Just about every deep-space exploration spacecraft has a fuel supply customized to get the job done, with some held in reserve for contingency maneuvers and other uncertainties. Fortunately, the Stardust mission navigation team did a great job, the spacecraft operated extremely well, and there was an adequate amount of contingency fuel aboard after its prime mission to make this new comet flyby possible – but just barely."

Just how much fuel is in Stardust's tanks for its final act?

"We estimate we have a little under three percent of the fuel the mission launched with," said Larson. "It is an estimate, because no one has invented an entirely reliable fuel gauge for spacecraft. There are some excellent techniques with which we have made these estimates, but they are still estimates."

One of the ways mission planners can approximate fuel usage is to look at the history of the vehicle's flight and how many times and for how long its rocket motors have fired. When that was done for Stardust, the team found their spacecraft's attitude and translational thrusters had fired almost half-a-million times each over the past 12 years.

"There is always a little plus and minus with each burn. When you add them all up, that is how you get the range of possible answers on how much fuel was used," said Larson.

Fuel is not the only question that needs to be addressed on the way to a second comet encounter. Added into the mix is the fact a comet near the sun can fire off jets of gas and dust that can cause a change in its orbit, sometimes in unexpected ways, potentially causing a precisely designed cometary approach to become less precise. Then there are the distances involved. Stardust will fly past comet Tempel 1 on almost the opposite side of the sun from Earth, making deep-space communication truly, well, deep space. Add into the mix the Stardust spacecraft itself. Launched when Bill Clinton was in the White House, Stardust has been cooked and frozen countless times during its trips from the inner to outer solar system. It has also weathered its fair share of radiation-packed solar storms. But while its fuel tank may be running near-empty, that doesn't mean Stardust doesn't have anything left in the tank.

"All this mission's challenges are just that – challenges," said Larson. "We believe our team and our spacecraft are up to meeting every one of them, and we're looking forward to seeing what Tempel 1 looks like these days."

The Final Payoff

Larson, Veverka and the world will get their chance beginning a few hours after the encounter on Monday, Feb. 14, at about 8:56 p.m. PST (11:56 p.m. EST), when the first of 72 bonus-round images of the nucleus of comet Tempel 1 are downlinked.

All images of the comet will be taken by the spacecraft's navigation camera – an amalgam of spare flight-ready hardware left over from previous NASA missions: Voyager (launched in 1977), Galileo (launched in 1989), and Cassini (launched in 1997). Each image will take about 15 minutes to transmit. The first five images to be received and processed on the ground are expected to include a close up of Tempel 1's nucleus. All data from the flyby (including the images and science data obtained by the spacecraft's two onboard dust experiments) are expected to take about 10 hours to reach the ground.

Stardust-NExT is a low-cost mission that will expand the investigation of comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of Technology in Pasadena, manages Stardust-NExT for the NASA Science Mission Directorate, Washington, D.C. Joe Veverka of Cornell University, Ithaca, N.Y., is the mission's principal investigator. Lockheed Martin Space Systems, Denver Colo., built the spacecraft and manages day-to-day mission operations.

More information about Stardust-NExT is online at: http://stardustnext.jpl.nasa.gov .

JPL Airborne Sensor to Study 'Rivers in the Sky'

2011-02-11T02:51:00.000-08:00

They're called atmospheric rivers - narrow regions in Earth's atmosphere that transport enormous amounts of water vapor across the Pacific or other regions.

Aptly nicknamed "rivers in the sky," they can transport enough water vapor in one day, on average, to flood an area the size of Maryland 0.3 meters (1 foot) deep, or about seven times the average daily flow of water from the Mississippi River into the Gulf of Mexico. The phenomenon was the subject of a recent major emergency preparedness scenario led by the U.S. Geological Survey, "ARkStorm," which focused on the possibility of a series of strong atmospheric rivers striking California - a scenario of flooding, wind and mudslides the USGS said could cause damages exceeding those of Hurricane Katrina in 2005.

While atmospheric rivers are responsible for great quantities of rain that can produce flooding, they also contribute to beneficial increases in snowpack. A series of atmospheric rivers fueled the strong winter storms that battered the U.S. West Coast from western Washington to Southern California from Dec. 10 to 22, 2010, producing 28 to 64 centimeters (11 to 25 inches) of rain in certain areas. The atmospheric rivers also contributed to the snowpack in the Sierras, which received 75 percent of its annual snow by Dec. 22, the first full day of winter.

To improve our understanding of how atmospheric rivers form and behave and evaluate the operational use of unmanned aircraft for investigating these phenomena, NASA scientists, aircraft and sensors will participate in a National Oceanic and Atmospheric Administration-led airborne field campaign slated to begin Feb. 11.

Called Winter Storms and Pacific Atmospheric Rivers, or WISPAR, the field campaign, which continues through the end of February, is designed to demonstrate new technology, contribute to our understanding of atmospheric rivers and assist NOAA in potentially conducting offshore monitoring of atmospheric rivers to aid in future weather predictions.

A NASA Global Hawk unmanned aircraft operated out of NASA's Dryden Flight Research Center in Southern California is scheduled to depart Dryden Friday morning, Feb. 11, on the campaign's first science flight. The 24-hour flight will study an atmospheric river currently developing in the Pacific Ocean off Hawaii that appears as though it will impact the Oregon-California coast this weekend. Aboard the Global Hawk will be new weather reconnaissance devices called dropsondes developed by the National Center for Atmospheric Research that will take temperature, wind and other readings as they descend through an atmospheric river. Also aboard will be an advanced water vapor sensor - the High-Altitude Monolithic Microwave Integrated Circuit Sounding Radiometer, or HAMSR - created by NASA's Jet Propulsion Laboratory in Pasadena, Calif.

The remote-sensing HAMSR instrument analyzes the heat radiation emitted by oxygen and water molecules in the atmosphere to determine their density and temperature. The instrument operates at microwave frequencies that can penetrate clouds, enabling it to determine temperature, humidity and cloud structure under all weather conditions. This capability is critical for studying atmospheric processes associated with bad weather, like the conditions present during atmospheric river events.

HAMSR Principal Investigator Bjorn Lambrigtsen of JPL says the instrument - the most accurate and sensitive of its kind in the world - will help scientists better understand these unique weather phenomena.

"The WISPAR campaign is intended to study the concentrated streams of tropical moisture that sometimes get connected with cold fronts and winter storms approaching the U.S. West Coast - sometimes called the pineapple express, since they often originate near Hawaii - which can result in very intense rain events," Lambrigtsen said. "HAMSR, flying on NASA's unpiloted Global Hawk well above the weather but close enough to get a much more detailed picture than is possible from a satellite, will be used to map out this phenomenon and answer scientific questions about the formation and structure of these systems."

NASA's Global Hawk is an ideal platform from which to conduct WISPAR science because it is able to fly long distances, stay aloft for more than 24 hours and travel at high and low altitudes that could be dangerous for humans. Lambrigtsen will be at Dryden in the Global Hawk Operations Center during the flights, using data from the sensor and other information to adjust the Global Hawk's flight track, as necessary, to optimize the sampling of the atmospheric rivers.

Lambrigtsen said the public can monitor the progress of the WISPAR science flights in real time on a WISPAR version of JPL's hurricane portal website at http://winterscience.jpl.nasa.gov/WISPAR2011/ . The site will display the most recent satellite images, the Global Hawk flight track and a real-time subset of HAMSR data.

For more information about WISPAR, visit: http://www.noaanews.noaa.gov/stories2011/20110210_atmosphericrivers.html . For more on HAMSR, see: http://microwavescience.jpl.nasa.gov/instruments/hamsr/ .

Surprise Hidden in Titan's Smog: Cirrus-Like Clouds

2011-02-10T01:26:00.000-08:00

Every day is a bad-air day on Saturn's largest moon, Titan. Blanketed by haze far worse than any smog belched out in Los Angeles, Beijing or even Sherlock Holmes' London, the moon looks like a dirty orange ball.

Described once as crude oil without the sulfur, the haze is made of tiny droplets of hydrocarbons with other, more noxious chemicals mixed in. Gunk.

Icky as it may sound, Titan is really the rarest of gems: the only moon in our solar system with an atmosphere worthy of a planet. This atmosphere comes complete with lightning, drizzle and occasionally a big, summer-downpour style of cloud made of methane or ethane-hydrocarbons that are best known for their role in natural gas.

Now, thin, wispy clouds of ice particles, similar to Earth's cirrus clouds, are being reported by Carrie Anderson and Robert Samuelson at NASA's Goddard Space Flight Center in Greenbelt, Md. The findings, published this week in the journal Icarus, were made using the composite infrared spectrometer on NASA's Cassini spacecraft.

Unlike Titan's brownish haze, the ice clouds have the pearly white appearance of freshly fallen snow. Their existence is the latest clue to the workings of Titan's intriguing atmosphere and its one-way "cycle" that delivers hydrocarbons and other organic compounds to the ground as precipitation. Those compounds don't evaporate to replenish the atmosphere, but somehow the supply has not run out yet.

"This is the first time we have been able to get details about these clouds," says Samuelson, an emeritus scientist at Goddard and the co-author of the paper. "Previously, we had a lot of information about the gases in Titan's atmosphere but not much about the [high-altitude] clouds."

Compared to the puffy methane and ethane clouds found before in a lower part of the atmosphere by both ground-based observers and in images taken by Cassini's imaging science subsystem and visual and infrared mapping spectrometer, these clouds are much thinner and located higher in the atmosphere. "They are very tenuous and very easy to miss," says Anderson, the paper's lead author. "The only earlier hints that they existed were faint glimpses that NASA's Voyager 1 spacecraft caught as it flew by Titan in 1980."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C.

The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The CIRS team is based at NASA's Goddard Space Flight Center in Greenbelt, Md., where the instrument was built.

Cassini Marks Holidays with Dramatic Views of Rhea

2011-02-09T00:39:00.000-08:00

Newly released for the holidays, images of Saturn's second largest moon Rhea obtained by NASA's Cassini spacecraft show dramatic views of fractures cutting through craters on the moon's surface, revealing a history of tectonic rumbling. The images are among the highest-resolution views ever obtained of Rhea.

"These recent, high-resolution Cassini images help us put Saturn's moon in the context of the moons' geological family tree," said Paul Helfenstein, Cassini imaging team associate, based at Cornell University, Ithaca, N.Y. "Since NASA's Voyager mission visited Saturn, scientists have thought of Rhea and Dione as close cousins, with some differences in size and density. The new images show us they're more like fraternal twins, where the resemblance is more than skin deep. This probably comes from their nearness to each other in orbit."

Cassini scientists designed the March 2010 and November 2009 encounters in part to search for a ring thought to encircle the moon. During the March flyby, Cassini made its closest- approach to Rhea's surface so far, swooping within 100 kilometers (62 miles) of the moon. Based on these observations, however, scientists have since discounted the possibility that Rhea might currently have a faint ring above its equator.

These flybys nonetheless yielded unique views of other features on the moon, including ones that are among the best ever obtained of the side of Rhea that always faces away from Saturn. Other views show a web of bright, "wispy" fractures resembling some that were first spotted on another part of Rhea by the two Voyager spacecraft in 1980 and 1981.

At that time, scientists thought the wispy markings on the trailing hemispheres – the sides of moons that face backward in the orbit around a planet – of Rhea and the neighboring moon Dione were possible cryovolcanic deposits, or the residue of icy material erupting. The low resolution of Voyager images prevented a closer inspection of these regions. Since July 2004, Cassini's imaging cameras have captured pictures the trailing hemispheres of both satellites several times at much higher resolution. The images have shown that the wispy markings are actually exposures of bright ice along the steep walls of long scarps, or lines of cliffs, that indicate tectonic activity produced the features rather than cryovolcanism.

Data collected by Cassini's imaging cameras in November 2009 showed the trailing hemisphere at unprecedented resolution. Scientists combined images taken about one hour apart to create a 3-D image of this terrain, revealing a set of closely spaced troughs that sometimes look linear and sometimes look sinuous. The 3-D image also shows uplifted blocks interspersed through the terrain that cut through older, densely cratered plains. While the densely cratered plains imply that Rhea has not experienced much internal activity since its early history that would have repaved the moon, these imaging data suggest that some regions have ruptured in response to tectonic stress more recently. Troughs and other fault topography cut through the two largest craters in the scene, which are not as scarred with smaller craters, indicating that these craters are comparatively young. In some places, material has moved downslope along the scarps and accumulated on the flatter floors.

A mosaic of the March flyby images shows bright, icy fractures cutting across the surface of the moon, sometimes at right angles to each other. A false-color view of the entire disk of the moon's Saturn-facing side reveals a slightly bluer area, likely related to different surface compositions or to different sizes and fine-scale textures of the grains making up the moon's icy soil.

The new images have also helped to enhance maps of Rhea, including the first cartographic atlas of features on the moon complete with names approved by the International Astronomical Union. Thanks to the recent mission extension, Cassini will continue to chart the terrain of this and other Saturnian moons with ever-improving resolution, especially for terrain at high northern latitudes, until 2017.

"The 11th of January 2011 will be especially exciting, when Cassini flies just 76 kilometers [47 miles] above the surface of Rhea," said Thomas Roatsch, a Cassini imaging team scientist based at the German Aerospace Center Institute of Planetary Research in Berlin. "These will be by far the best images we've ever had of Rhea's surface – details down to just a few meters will become recognizable."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute in Boulder, Colo.

Monster Cyclone Yasi Eyes Australia in NASA Image

2011-02-08T00:49:00.000-08:00

Mass evacuations are underway in the northeastern Australian state of Queensland in anticipation of what forecasters expect will be the largest cyclone ever to hit the continent in recorded history.

Yasi has intensified rapidly and currently has winds gusting up to 295 kilometers per hour (183 mph).

It is expected to maintain that intensity-equivalent to a Category Five hurricane on the Saffir-Simpson Scale--until landfall in northeastern Queensland between Cairns and Innisfail during the late evening local time on Feb. 2 (early morning Feb. 2 in the United States).

Shown here is the latest infrared image of Yasi from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. It was taken on Feb. 1, 2011, at 7:17 a.m. PST (10:17 a.m. EST). A distinct eye is visible, and the outer bands of the storm can be seen nearing the Australian coast.

The AIRS data create an accurate 3-D map of atmospheric temperature, water vapor and clouds, data that are useful to forecasters. The image shows the temperature of Yasi's cloud tops or the surface of Earth in cloud-free regions.

The coldest cloud-top temperatures appear in purple, indicating towering cold clouds and heavy precipitation. The infrared signal of AIRS does not penetrate through clouds. Where there are no clouds, AIRS reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.

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Monster Cyclone Yasi Eyes Australia in NASA Image

2011-02-07T00:43:00.000-08:00

Mass evacuations are underway in the northeastern Australian state of Queensland in anticipation of what forecasters expect will be the largest cyclone ever to hit the continent in recorded history.

Yasi has intensified rapidly and currently has winds gusting up to 295 kilometers per hour (183 mph). It is expected to maintain that intensity-equivalent to a Category Five hurricane on the Saffir-Simpson Scale--until landfall in northeastern Queensland between Cairns and Innisfail during the late evening local time on Feb. 2 (early morning Feb. 2 in the United States).

Shown here is the latest infrared image of Yasi from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. It was taken on Feb. 1, 2011, at 7:17 a.m. PST (10:17 a.m. EST). A distinct eye is visible, and the outer bands of the storm can be seen nearing the Australian coast.

The AIRS data create an accurate 3-D map of atmospheric temperature, water vapor and clouds, data that are useful to forecasters. The image shows the temperature of Yasi's cloud tops or the surface of Earth in cloud-free regions.

The coldest cloud-top temperatures appear in purple, indicating towering cold clouds and heavy precipitation. The infrared signal of AIRS does not penetrate through clouds. Where there are no clouds, AIRS reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red

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Monster Cyclone Yasi Eyes Australia in NASA Image

2011-02-04T02:42:00.000-08:00

Mass evacuations are underway in the northeastern Australian state of Queensland in anticipation of what forecasters expect will be the largest cyclone ever to hit the continent in recorded history.

Yasi has intensified rapidly and currently has winds gusting up to 295 kilometers per hour (183 mph). It is expected to maintain that intensity-equivalent to a Category Five hurricane on the Saffir-Simpson Scale--until landfall in northeastern Queensland between Cairns and Innisfail during the late evening local time on Feb. 2 (early morning Feb. 2 in the United States).

Shown here is the latest infrared image of Yasi from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. It was taken on Feb. 1, 2011, at 7:17 a.m. PST (10:17 a.m. EST). A distinct eye is visible, and the outer bands of the storm can be seen nearing the Australian coast.

The AIRS data create an accurate 3-D map of atmospheric temperature, water vapor and clouds, data that are useful to forecasters. The image shows the temperature of Yasi's cloud tops or the surface of Earth in cloud-free regions.

The coldest cloud-top temperatures appear in purple, indicating towering cold clouds and heavy precipitation. The infrared signal of AIRS does not penetrate through clouds. Where there are no clouds, AIRS reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.

Cassini Sends Back Postcards of Saturn Moons

2011-02-03T00:57:00.000-08:00

NASA's Cassini spacecraft passed by several of Saturn's intriguing moons, snapping images along the way. Cassini passed within about 60,000 kilometers (37,282 miles) of Enceladus and 28,000 kilometers (17,398 miles) of Helene. It also caught a glimpse of Mimas in front of Saturn's rings.

In one of the images, Cassini is looking at the famous jets erupting from the south polar terrain of Enceladus.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

An Astronomer's Field of Dreams

2011-02-01T02:06:00.000-08:00

An innovative new radio telescope array under construction in central New Mexico will eventually harness the power of more than 13,000 antennas and provide a fresh eye to the sky.

The antennas, which resemble droopy ceiling fans, form the Long Wavelength Array, designed to survey the sky from horizon to horizon over a wide range of frequencies.

The University of New Mexico leads the project, and NASA's Jet Propulsion Laboratory, Pasadena, Calif., provides the advanced digital electronic systems, which represent a major component of the observatory.

The first station in the Long Wavelength Array, with 256 antennas, is scheduled to start surveying the sky by this summer. When complete, the Long Wavelength Array will consist of 53 stations, with a total of 13,000 antennas strategically placed in an area nearly 400 kilometers (248 miles) in diameter. The antennas will provide sensitive, high-resolution images of a region of the sky hundreds of times larger than the full moon. These images could reveal radio waves coming from planets outside our solar system, and thus would turn out to be a new way to detect these worlds. In addition to planets, the telescope will pick up a host of other cosmic phenomena.

"We'll be looking for the occasional celestial flash," said Joseph Lazio, a radio astronomer at JPL. "These flashes can be anything from explosions on surfaces of nearby stars, deaths of distant stars, exploding black holes, or even perhaps transmissions by other civilizations." JPL scientists are working with multi-institutional teams to explore this new area of astronomy. Lazio is lead author of an article reporting scientific results from the Long Wavelength Demonstrator Array, a precursor to the new array, in the December 2010 issue of Astronomical Journal.

The new Long Wavelength Array will operate in the radio-frequency range of 20 to 80 megahertz, corresponding to wavelengths of 15 meters to 3.8 meters (49.2 feet to 12.5 feet). These frequencies represent one of the last and most poorly explored regions of the electromagnetic spectrum.

In recent years, a few factors have triggered revived interest in radio astronomy at these frequencies. The cost and technology required to build these low-frequency antennas has improved significantly. Also, advances in computing have made the demands of image processing more attainable. The combination of cost-effective hardware and technology gives scientists the ability to return to these wavelengths and obtain a much better view of the universe.

The predecessor Long Wavelength Demonstrator Array was also in New Mexico. It was successful in identifying radio flashes, but all of them came from non-astronomy targets -- either the sun, or meteors reflecting TV signals high in Earth's atmosphere. Nonetheless, its findings indicate how future searches using the Long Wavelength Array technology might lead to new discoveries.

Radio astronomy was born at frequencies below 100 megahertz and developed from there. The discoveries and innovations at this frequency range helped pave the way for modern astronomy. Perhaps one of the most important contributions made in radio astronomy was by a young graduate student at New Hall (since renamed Murray Edwards College) of the University of Cambridge, U.K. Jocelyn Bell discovered the first hints of radio pulsars in 1967, a finding that was later awarded a Nobel Prize. Pulsars are neutron stars that beam radio waves in a manner similar to a lighthouse beacon.

Long before Bell's discovery, astronomers believed that neutron stars, remnants of certain types of supernova explosions, might exist. At the time, however, the prediction was that these cosmic objects would be far too faint to be detected. When Bell went looking for something else, she stumbled upon neutron stars that were in fact pulsing with radio waves -- the pulsars. Today about 2,000 pulsars are known, but within the past decade, a number of discoveries have hinted that the radio sky might be far more dynamic than suggested by just pulsars.

"Because nature is more clever than we are, it's quite possible that we will discover something we haven't thought of," said Lazio.

More information on the Long Wavelength Array is online at: http://lwa.unm.edu .

The Long Wavelength Array project is led by the University of New Mexico, Albuquerque, N.M., and includes the Los Alamos National Laboratory, N.M., the United States Naval Research Laboratories, Washington, and NASA's Jet Propulsion Laboratory, Pasadena, Calif. The California Institute of Technology manages JPL for NASA.

Runaway Star Plows Through Space

2011-01-31T01:14:00.000-08:00

A massive star flung away from its former companion is plowing through space dust. The result is a brilliant bow shock, seen here as a yellow arc in a new image from NASA's Wide-field Infrared Survey Explorer, or WISE.

The star, named Zeta Ophiuchi, is huge, with a mass of about 20 times that of our sun. In this image, in which infrared light has been translated into visible colors we see with our eyes, the star appears as the blue dot inside the bow shock.

Zeta Ophiuchi once orbited around an even heftier star. But when that star exploded in a supernova, Zeta Ophiuchi shot away like a bullet. It's traveling at a whopping 54,000 miles per hour (or 24 kilometers per second), and heading toward the upper left area of the picture.

As the star tears through space, its powerful winds push gas and dust out of its way and into what is called a bow shock. The material in the bow shock is so compressed that it glows with infrared light that WISE can see. The effect is similar to what happens when a boat speeds through water, pushing a wave in front of it.

This bow shock is completely hidden in visible light. Infrared images like this one from WISE are therefore important for shedding new light on the region.

JPL manages and operates WISE for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by NASA's Goddard Space Flight Center, Greenbelt, Md.

The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise, http://wise.astro.ucla.edu and http://www.jpl.nasa.gov/wise .

An Astronomer's Field of Dreams

2011-01-27T01:54:00.000-08:00

An innovative new radio telescope array under construction in central New Mexico will eventually harness the power of more than 13,000 antennas and provide a fresh eye to the sky.

The antennas, which resemble droopy ceiling fans, form the Long Wavelength Array, designed to survey the sky from horizon to horizon over a wide range of frequencies.

The University of New Mexico leads the project, and NASA's Jet Propulsion Laboratory, Pasadena, Calif., provides the advanced digital electronic systems, which represent a major component of the observatory.

The first station in the Long Wavelength Array, with 256 antennas, is scheduled to start surveying the sky by this summer. When complete, the Long Wavelength Array will consist of 53 stations, with a total of 13,000 antennas strategically placed in an area nearly 400 kilometers (248 miles) in diameter. The antennas will provide sensitive, high-resolution images of a region of the sky hundreds of times larger than the full moon. These images could reveal radio waves coming from planets outside our solar system, and thus would turn out to be a new way to detect these worlds. In addition to planets, the telescope will pick up a host of other cosmic phenomena.

"We'll be looking for the occasional celestial flash," said Joseph Lazio, a radio astronomer at JPL. "These flashes can be anything from explosions on surfaces of nearby stars, deaths of distant stars, exploding black holes, or even perhaps transmissions by other civilizations." JPL scientists are working with multi-institutional teams to explore this new area of astronomy. Lazio is lead author of an article reporting scientific results from the Long Wavelength Demonstrator Array, a precursor to the new array, in the December 2010 issue of Astronomical Journal.

The new Long Wavelength Array will operate in the radio-frequency range of 20 to 80 megahertz, corresponding to wavelengths of 15 meters to 3.8 meters (49.2 feet to 12.5 feet). These frequencies represent one of the last and most poorly explored regions of the electromagnetic spectrum.

In recent years, a few factors have triggered revived interest in radio astronomy at these frequencies. The cost and technology required to build these low-frequency antennas has improved significantly. Also, advances in computing have made the demands of image processing more attainable. The combination of cost-effective hardware and technology gives scientists the ability to return to these wavelengths and obtain a much better view of the universe.
The predecessor Long Wavelength Demonstrator Array was also in New Mexico. It was successful in identifying radio flashes, but all of them came from non-astronomy targets -- either the sun, or meteors reflecting TV signals high in Earth's atmosphere. Nonetheless, its findings indicate how future searches using the Long Wavelength Array technology might lead to new discoveries.

Radio astronomy was born at frequencies below 100 megahertz and developed from there. The discoveries and innovations at this frequency range helped pave the way for modern astronomy. Perhaps one of the most important contributions made in radio astronomy was by a young graduate student at New Hall (since renamed Murray Edwards College) of the University of Cambridge, U.K. Jocelyn Bell discovered the first hints of radio pulsars in 1967, a finding that was later awarded a Nobel Prize. Pulsars are neutron stars that beam radio waves in a manner similar to a lighthouse beacon.

Long before Bell's discovery, astronomers believed that neutron stars, remnants of certain types of supernova explosions, might exist. At the time, however, the prediction was that these cosmic objects would be far too faint to be detected. When Bell went looking for something else, she stumbled upon neutron stars that were in fact pulsing with radio waves -- the pulsars. Today about 2,000 pulsars are known, but within the past decade, a number of discoveries have hinted that the radio sky might be far more dynamic than suggested by just pulsars.

"Because nature is more clever than we are, it's quite possible that we will discover something we haven't thought of," said Lazio.

More information on the Long Wavelength Array is online at: http://lwa.unm.edu .

The Long Wavelength Array project is led by the University of New Mexico, Albuquerque, N.M., and includes the Los Alamos National Laboratory, N.M., the United States Naval Research Laboratories, Washington, and NASA's Jet Propulsion Laboratory, Pasadena, Calif. The California Institute of Technology manages JPL for NASA.

Arcadia High School Wins Regional Science Bowl

2011-01-25T00:37:00.000-08:00

A team of five students, four competitors and an alternate, from Arcadia High School won the Regional Science Bowl competition on Saturday, Jan. 22, at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"It came down to one question at the very end," said Arcadia team captain Derek Chou. "And I remember reading about that very topic the night before!"

When the final buzzer rang, the score was Arcadia 118, and 122 for Troy High School from Fullerton, Calif. The ball was in Arcadia's court and a wrong answer would mean the end of the road for them. With the championship on the line, Arcadia rose to the occasion and answered correctly, earning 10 points for a final score of Arcadia 128 and Troy 122.

"When the moderator said, 'Correct,' our bodies were flooded with epinephrine," said Arcadia High School student Andrew Wang.

What was the question? "In order to replenish the supply of steam at the geothermal plant called The Geysers, which of the following does an underground pipeline deliver? W) wastewater X) river water Y) ocean water Z) rain water. " (See answer at the bottom of this article)

Wang, Chou and their teammates will receive an all-expense paid trip to Washington, D.C., to participate in the National Science Bowl finals. This year's finals will run from April 28 to May 2.

The national competition is sponsored by the U.S. Department of Energy. The regional competition is held at JPL, a division of the California of Institute of Technology in California. JPL hosts one of the two Southern California regional events. This year, 23 teams competed at the JPL event.

Each team was made up of four students, a student alternate and a teacher who served as an advisor and coach. The students answered multiple-choice or short-answer questions in biology, chemistry, physics, mathematics, and Earth and space sciences. The competition, which attracts about 17,000 middle and high school students nationwide, is designed to inspire students to pursue a career in science or math.

Half a Million Take a Gander at Space

2011-01-24T00:48:00.000-08:00

The first-ever NASA/JPL iPhone application, Space Images, has reached 500,000 downloads, just as JPL prepares to release its newest version of the free app.

Space Images features breathtaking views of Earth, the solar system and the universe beyond.

Soon after its release in January 2010, Space Images was selected as a "Staff Favorite" in iTunes and quickly became a top app in the Education category. It has since received praise from users for its extensive and stunning collection of images taken by NASA/JPL spacecraft and for its educational uses.

The new version, Space Images 2.0, optimized for iPad and iPhone 4, brings even more stellar photos to viewers' fingertips, plus videos, Facebook and Twitter connectivity, and a new format that makes it easier to browse through photos at a higher resolution. It will be available in the iTunes Store this spring.

Droid more your style? Space Images 2.0 for Android devices is coming soon.

Visit http://bit.ly/e2yy4y to download Space Images free in the iTunes App Store. Explore more mobile offerings from JPL at http://www.jpl.nasa.gov/onthego/index.cfm?cid=500kweb.

NASA Spacecraft Prepares for Valentine's Day Comet Rendezvous

2011-01-21T01:58:00.000-08:00

NASA's Stardust-NExT spacecraft is nearing a celestial date with comet Tempel 1 at approximately 8:37 p.m. PST (11:37 p.m. EST), on Feb. 14. The mission will allow scientists for the first time to look for changes on a comet's surface that occurred following an orbit around the sun.

The Stardust-NExT, or New Exploration of Tempel, spacecraft will take high-resolution images during the encounter, and attempt to measure the composition, distribution, and flux of dust emitted into the coma, or material surrounding the comet's nucleus. Data from the mission will provide important new information on how Jupiter-family comets evolved and formed.

The mission will expand the investigation of the comet initiated by NASA's Deep Impact mission. In July 2005, the Deep Impact spacecraft delivered an impactor to the surface of Tempel 1 to study its composition. The Stardust spacecraft may capture an image of the crater created by the impactor. This would be an added bonus to the huge amount of data that mission scientists expect to obtain.

"Every day we are getting closer and closer and more and more excited about answering some fundamental questions about comets," said Joe Veverka, Stardust-NExT principal investigator at Cornell University, Ithaca, N.Y. "Going back for another look at Tempel 1 will provide new insights on how comets work and how they were put together four-and-a-half billion years ago."

At approximately 336 million kilometers (209 million miles) away from Earth, Stardust-NExT will be almost on the exact opposite side of the solar system at the time of the encounter. During the flyby, the spacecraft will take 72 images and store them in an onboard computer.

Initial raw images from the flyby will be sent to Earth for processing that will begin at approximately midnight PST (3 a.m. EST) on Feb. 15. Images are expected to be available at approximately 1:30 a.m. PST (4:30 a.m. EST).

As of today, the spacecraft is approximately 24.6 million kilometers (15.3 million miles) away from its encounter. Since 2007, Stardust-NExT executed eight flight path correction maneuvers, logged four circuits around the sun and used one Earth gravity assist to meet up with Tempel 1.

Another three maneuvers are planned to refine the spacecraft's path to the comet. Tempel 1's orbit takes it as close in to the sun as the orbit of Mars and almost as far away as the orbit of Jupiter. The spacecraft is expected to fly past the nearly 6-kilometer-wide comet (3.7 miles) at a distance of approximately 200 kilometers (124 miles).

In 2004, the Stardust mission became the first to collect particles directly from comet Wild 2, as well as interstellar dust. Samples were returned in 2006 for study via a capsule that detached from the spacecraft and parachuted to the ground southwest of Salt Lake City. Mission controllers placed the still viable Stardust spacecraft on a trajectory that could potentially reuse the flight system if a target of opportunity presented itself.

In January 2007, NASA re-christened the mission Stardust-NExT and began a four-and-a-half year journey to comet Tempel 1.

"You could say our spacecraft is a seasoned veteran of cometary campaigns," said Tim Larson, project manager for Stardust-NExT at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It's been half-way to Jupiter, executed picture-perfect flybys of an asteroid and a comet, collected cometary material for return to Earth, then headed back out into the void again, where we asked it to go head-to-head with a second comet nucleus."

The mission team expects this flyby to write the final chapter of the spacecraft's success-filled story. The spacecraft is nearly out of fuel as it approaches 12 years of space travel, logging almost 6 billion kilometers (3.7 billion miles) since launch in 1999. This flyby and planned post-encounter imaging are expected to consume the remaining fuel.

JPL manages the mission for the agency's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft and manages day-to-day mission operations. JPL is managed by the California Institute of Technology, Pasadena.

For more information about the Stardust-NExT mission, visit: http://stardustnext.jpl.nasa.gov/

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Cassini Rocks Rhea Rendezvous

2011-01-20T00:41:00.000-08:00

NASA's Cassini spacecraft has successfully completed its closest flyby of Saturn's moon Rhea, returning raw images of the icy moon's surface.

Pictures of the Rhea surface taken around the time of closest approach at 4:53 a.m. UTC on Jan. 11, 2011, which was 8:53 p.m. PST, Jan. 10, show shadowy craters at a low sun angle. A portrait of bright, icy Rhea also captures Saturn's rings and three other moons clearly visible in the background.

Images obtained by Cassini's imaging science subsystem show an old, inert surface saturated with craters, just like the oldest parts of Earth's moon. But there appear to be some straight faults that were formed early in Rhea's history, which never developed the full-blown activity seen on another of Saturn's moons, Enceladus.

The flyby of Rhea also presented scientists with their best available chance to study how often tiny meteoroids bombard the moon's surface. Scientists are now sifting through data collected on the close flyby by the cosmic dust analyzer and the radio and plasma wave science instrument. They will use the data to deduce how often objects outside the Saturn system contaminate Saturn's rings, and to improve estimates of how old the rings are.

Scientists using Cassini's fields and particles instruments are also looking through their data to see if they learned more about Rhea's very thin oxygen-and-carbon-dioxide atmosphere and the interaction between Rhea and the particles within Saturn's magnetosphere, the magnetic bubble around the planet.

At closest approach, Cassini passed within about 69 kilometers (43 miles) of the surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

For more information about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

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Cosmology Standard Candle not so Standard After All

2011-01-19T01:31:00.000-08:00

Astronomers have turned up the first direct proof that "standard candles" used to illuminate the size of the universe, termed Cepheids, shrink in mass, making them not quite as standard as once thought.

The findings, made with NASA's Spitzer Space Telescope, will help astronomers make even more precise measurements of the size, age and expansion rate of our universe.

Standard candles are astronomical objects that make up the rungs of the so-called cosmic distance ladder, a tool for measuring the distances to farther and farther galaxies. The ladder's first rung consists of pulsating stars called Cepheid variables, or Cepheids for short.

Measurements of the distances to these stars from Earth are critical in making precise measurements of even more distant objects. Each rung on the ladder depends on the previous one, so without accurate Cepheid measurements, the whole cosmic distance ladder would come unhinged.

Now, new observations from Spitzer show that keeping this ladder secure requires even more careful attention to Cepheids. The telescope's infrared observations of one particular Cepheid provide the first direct evidence that these stars can lose mass-or essentially shrink. This could affect measurements of their distances.

"We have shown that these particular standard candles are slowly consumed by their wind," said Massimo Marengo of Iowa State University, Ames, Iowa, lead author of a recent study on the discovery appearing in the Astronomical Journal. "When using Cepheids as standard candles, we must be extra careful because, much like actual candles, they are consumed as they burn."

The star in the study is Delta Cephei, which is the namesake for the entire class of Cepheids. It was discovered in 1784 in the constellation Cepheus, or the King. Intermediate-mass stars can become Cepheids when they are middle-aged, pulsing with a regular beat that is related to how bright they are.

This unique trait allows astronomers to take the pulse of a Cepheid and figure out how bright it is intrinsically-or how bright it would be if you were right next to it. By measuring how bright the star appears in the sky, and comparing this to its intrinsic brightness, it can then be determined how far away it must be.

This calculation was famously performed by astronomer Edwin Hubble in 1924, leading to the revelation that our galaxy is just one of many in a vast cosmic sea. Cepheids also helped in the discovery that our universe is expanding and galaxies are drifting apart.

Cepheids have since become reliable rungs on the cosmic distance ladder, but mysteries about these standard candles remain. One question has been whether or not they lose mass. Winds from a Cepheid star could blow off significant amounts of gas and dust, forming a dusty cocoon around the star that would affect how bright it appears. This, in turn, would affect calculations of its distance. Previous research had hinted at such mass loss, but more direct evidence was needed.

Marengo and his colleague used Spitzer's infrared vision to study the dust around Delta Cephei. This particular star is racing along through space at high speeds, pushing interstellar gas and dust into a bow shock up ahead. Luckily for the scientists, a nearby companion star happens to be lighting the area, making the bow shock easier to see. By studying the size and structure of the shock, the team was able to show that a strong, massive wind from the star is pushing against the interstellar gas and dust. In addition, the team calculated that this wind is up to one million times stronger than the wind blown by our sun. This proves that Delta Cephei is shrinking slightly.

Follow-up observations of other Cepheids conducted by the same team using Spitzer have shown that other Cepheids, up to 25 percent observed, are also losing mass.

"Everything crumbles in cosmology studies if you don't start up with the most precise measurements of Cepheids possible," said Pauline Barmby of the University of Western Ontario, Canada, lead author of the follow-up Cepheid study published online Jan. 6 in the Astronomical Journal. "This discovery will allow us to better understand these stars, and use them as ever more precise distance indicators."

Other authors of this study include N. R. Evans and G.G. Fazio of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.; L.D. Matthews of Harvard-Smithsonian and the Massachusetts Institute of Technology Haystack Observatory, Westford; G. Bono of the Università di Roma Tor Vergata and the INAF-Osservatorio Astronomico di Roma in Rome, Italy; D.L. Welch of the McMaster University, Ontario, Canada; M. Romaniello of the European Southern Observatory, Garching, Germany; D. Huelsman of Harvard-Smithsonian and University of Cincinnati, Ohio; and K. Y. L. Su of the University of Arizona, Tucson.

The Spitzer observations were made before it ran out of its liquid coolant in May 2009 and began its warm mission.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

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