NASA Satellite Finds Earth's Clouds are Getting Lower

Earth's clouds got a little lower -- about one percent on average -- during the first decade of this century, finds a new NASA-funded university study based on NASA satellite data. The results have potential implications for future global climate.

Scientists at the University of Auckland in New Zealand analyzed the first 10 years of global cloud-top height measurements (from March 2000 to February 2010) from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra spacecraft. The study, published recently in the journal Geophysical Research Letters, revealed an overall trend of decreasing cloud height. Global average cloud height declined by around one percent over the decade, or by around 100 to 130 feet (30 to 40 meters). Most of the reduction was due to fewer clouds occurring at very high altitudes.

Lead researcher Roger Davies said that while the record is too short to be definitive, it provides a hint that something quite important might be going on. Longer-term monitoring will be required to determine the significance of the observation for global temperatures.

A consistent reduction in cloud height would allow Earth to cool to space more efficiently, reducing the surface temperature of the planet and potentially slowing the effects of global warming. This may represent a "negative feedback" mechanism - a change caused by global warming that works to counteract it. "We don't know exactly what causes the cloud heights to lower," says Davies. "But it must be due to a change in the circulation patterns that give rise to cloud formation at high altitude."

NASA's Terra spacecraft is scheduled to continue gathering data through the remainder of this decade. Scientists will continue to monitor the MISR data closely to see if this trend continues.

For more information, visit: http://www.auckland.ac.nz/uoa/home/news/template/news_item.jsp?cid=466683 .

NASA's Galaxy Evolution Explorer in Standby Mode

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/ .

Durable NASA Rover Beginning Ninth Year of Mars Work

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

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

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

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

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 .

Cassini Testing Part of Its Radio System

Engineers with NASA's Cassini mission are conducting diagnostic testing on a part of the spacecraft's radio system after its signal was not detected on Earth during a tracking pass in late December. The spacecraft has been communicating with Earth using a backup part.

The issue occurred with the ultra-stable oscillator, which is used for one type of radio science experiment and also as a means of sending data back to Earth. The spacecraft is currently using an auxiliary oscillator, whose frequency stability is adequate for transmitting data from the spacecraft to Earth. Tests later this month will help mission managers decide whether it will be possible to bring the ultra-stable oscillator back into service.

Some of the data collected for the radio science experiment using the auxiliary oscillator will be of lesser quality than that from the ultra-stable oscillator. Signals used for occultation experiments - where scientists analyze how radio signals are affected as they travel through Saturn's rings or the atmospheres of Saturn and its moons back to Earth - will be of lesser quality. A second kind of radio science investigation using gravity measurements to probe the internal structure of Saturn or its moons will not be affected. Cassini carries 12 science experiments.

The cause is still under investigation, but age may be a factor. The spacecraft launched in 1997 and has orbited Saturn since 2004. Cassini completed its prime mission in 2008 and has had two additional mission extensions. This is the first time its ultra-stable oscillator has had an issue.

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.

For more information about the mission, visit: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini.

NASA Finds Russian Runoff Freshening Canadian Arctic

A new NASA and University of Washington study allays concerns that melting Arctic sea ice could be increasing the amount of freshwater in the Arctic enough to have an impact on the global "ocean conveyor belt" that redistributes heat around our planet.

Lead author and oceanographer Jamie Morison of the University of Washington's Applied Physics Laboratory in Seattle, and his team, detected a previously unknown redistribution of freshwater during the past decade from the Eurasian half of the Arctic Ocean to the Canadian half. Yet despite the redistribution, they found no change in the net amount of freshwater in the Arctic that might signal a change in the conveyor belt.

The team attributes the redistribution to an eastward shift in the path of Russian runoff through the Arctic Ocean, which is tied to an increase in the strength of the Northern Hemisphere's west-to-east atmospheric circulation, known as the Arctic Oscillation. The resulting counterclockwise winds changed the direction of ocean circulation, diverting upper-ocean freshwater from Russian rivers away from the Arctic's Eurasian Basin, between Russia and Greenland, to the Beaufort Sea in the Canada Basin bordered by the United States and Canada. The stronger Arctic Oscillation is associated with two decades of reduced atmospheric pressure over the Russian side of the Arctic. Results of the NASA- and National Science Foundation-funded study are published Jan. 5 in the journal Nature.

Between 2003 and 2008, the resulting redistribution of freshwater was equivalent to adding 10 feet (3 meters) of freshwater over the central Beaufort Sea.

The freshwater changes were seen between 2005 and 2008 by combining ocean bottom pressure, or mass, data from NASA's Gravity Recovery and Climate Experiment satellites with ocean height data from NASA's ICESat satellite. By calculating the difference between the two sets of measurements, the team was able to map changes in freshwater content over the entire Arctic Ocean, including regions where direct water sample measurements are not available.

"Knowing the pathways of freshwater is important to understanding global climate because freshwater protects sea ice by helping create a strongly stratified cold layer between the ice and warmer, saltier water below that comes into the Arctic from the Atlantic Ocean," said Morison. "The reduction in freshwater entering the Eurasian Basin resulting from the Arctic Oscillation change could contribute to sea ice declines in that part of the Arctic."

Source: http://www.jpl.nasa.gov/news/news.cfm?release=2012-002

NASA's Twin Grail Spacecraft

The second of NASA's two Gravity Recovery And Interior Laboratory (GRAIL) spacecraft has successfully completed its planned main engine burn and is now in lunar orbit. Working together, GRAIL-A and GRAIL-B will study the moon as never before.

"NASA greets the new year with a new mission of exploration," said NASA Administrator Charles Bolden. "The twin GRAIL spacecraft will vastly expand our knowledge of our moon and the evolution of our own planet. We begin this year reminding people around the world that NASA does big, bold things in order to reach for new heights and reveal the unknown."

GRAIL-B achieved lunar orbit at 2:43 p.m. PST (5:43 p.m. EST) today. GRAIL-A successfully completed its burn yesterday at 2 p.m. PST (5 p.m. EST). The insertion maneuvers placed the spacecraft into a near-polar, elliptical orbit with an orbital period of approximately 11.5 hours. Over the coming weeks, the GRAIL team will execute a series of burns with each spacecraft to reduce their orbital period to just under two hours. At the start of the science phase in March 2012, the two GRAILs will be in a near-polar, near-circular orbit with an altitude of about 34 miles (55 kilometers).

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.

Read more: http://www.jpl.nasa.gov/news/news.cfm?release=2012-001

Cassini Delivers Holiday Treats From Saturn

No team of reindeer, but radio signals flying clear across the solar system from NASA's Cassini spacecraft have delivered a holiday package of glorious images. The pictures, from Cassini's imaging team, show Saturn's largest, most colorful ornament, Titan, and other icy baubles in orbit around this splendid planet.

The release includes images of satellite conjunctions in which one moon passes in front of or behind another. Cassini scientists regularly make these observations to study the ever-changing orbits of the planet's moons. But even in these routine images, the Saturnian system shines. A few of Saturn's stark, airless, icy moons appear to dangle next to the orange orb of Titan, the only moon in the solar system with a substantial atmosphere. Titan's atmosphere is of great interest because of its similarities to the atmosphere believed to exist long ago on the early Earth.

The images are online at: http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org .

While it may be wintry in Earth's northern hemisphere, it is currently northern spring in the Saturnian system and it will remain so for several Earth years. Current plans to extend the Cassini mission through 2017 will supply a continued bounty of scientifically rewarding and majestic views of Saturn and its moons and rings, as spectators are treated to the passage of northern spring and the arrival of summer in May 2017.

"As another year traveling this magnificent sector of our solar system draws to a close, all of us on Cassini wish all of you a very happy and peaceful holiday season, " said Carolyn Porco, Cassini imaging team lead at the Space Science Institute, Boulder, Colo.

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

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.

NASA Shuts Doors, Pulls Plug on Shuttle Discovery

NASA powered down the space shuttle Discovery for a final time Friday (Dec. 16), more than 28 years after the agency's retired fleet leader first came alive. The vehicle was "unplugged" inside Orbiter Processing Facility-1 (OPF-1) at the Kennedy Space Center in Florida.

The electrical shutdown, which came soon after technicians closed the shuttle's twin 60-foot (18.3-meter) long payload bay doors, was a milestone in Discovery's transition from a space-worthy orbiter to a museum exhibit. The shuttle, the oldest of NASA's remaining orbiters, is destined for display next spring at the Smithsonian National Air and Space Museum's Steven F. Udvar-Hazy Center in Virginia.

Discovery's cargo hold — which carried to orbit the Hubble Space Telescope and Ulysses solar probe along with modules for the International Space Station and more than a dozen satellites — was closed for what may be its last time. The Smithsonian plans to display the shuttle with its bay doors shut, at least initially.

The power down was much more permanent. Though Discovery's three electricity-generating fuel cells were reinstalled last week, they were first drained of all their reactants, and their feed lines were purged. Other than serving as an engineering example for researchers, they will never work again.

As a result, the shuttle's glass cockpit with its multiple computer screens and its backlit switches will from now on be dark. [Photos: See Inside Space Shuttle Discovery]

Since landing back on Earth after its 39th and final mission in March, Discovery has been carefully taken apart to preserve some of its components for future use while making the vehicle safe for public display. Its engines have been removed and replaced with replicas and its thrusters cleaned of their hazardous materials.

Inside its crew cabin, Discovery's waste collection system — otherwise known as its toilet — was removed, cleaned, and replaced, and its flight deck configured to appear ready for another mission, one that will never come. As with the fuel cells, the Smithsonian requested NASA keep Discovery as complete as possible so as to serve as a resource for future study.

Discovery is targeted to make one last flight in April 2012, though not under its own power and well within the atmosphere. Ferried atop NASA's modified Boeing 747 carrier aircraft, the shuttle will be flown to Dulles Airport in Virginia. There it will be unloaded by cranes and rolled into the Udvar-Hazy's James S. McDonnell Space Hangar as its centerpiece attraction.

Discovery will replace the prototype shuttle Enterprise, which the Udvar-Hazy has displayed since 2003. Enterprise in turn will be flown to New York City, where it is to go on exhibit at the Intrepid Sea, Air & Space Museum.

Mars Science Laboratory Meets its Match in Florida

In preparation for launch later this year, the "back shell powered descent vehicle" configuration containing NASA's Mars Science Laboratory rover, Curiosity, has been placed on the spacecraft's heat shield.

The matchup was performed by technicians at NASA's Kennedy Space Center in Florida.

The heat shield and the spacecraft's back shell form an aeroshell that encapsulates and protects the rover from the intense heat it will experience during the final leg of the trip to Mars-the friction-filled descent through the Martian atmosphere.

The mission is scheduled for launch from Cape Canaveral Air Force Station during the period from Nov. 25 to Dec. 18. Arrival at Gale Crater on Mars is expected in August 2012.

After arrival, the Curiosity rover will investigate whether the landing region has had environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed.

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

More information about Curiosity is online at: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ .

Saturn's Moon Enceladus Spreads Its Influence

Chalk up one more feat for Saturn’s intriguing moon Enceladus. The small, dynamic moon spews out dramatic plumes of water vapor and ice -- first seen by NASA’s Cassini spacecraft in 2005. It possesses simple organic particles and may house liquid water beneath its surface. Its geyser-like jets create a gigantic halo of ice, dust and gas around Enceladus that helps feed Saturn’s E ring. Now, thanks again to those icy jets, Enceladus is the only moon in our solar system known to influence substantially the chemical composition of its parent planet.

In June, the European Space Agency announced that its Herschel Space Observatory, which has important NASA contributions, had found a huge donut-shaped cloud, or torus, of water vapor created by Enceladus encircling Saturn. The torus is more than 373,000 miles (600,000 kilometers) across and about 37,000 miles (60,000 kilometers) thick. It appears to be the source of water in Saturn’s upper atmosphere.

Though it is enormous, the cloud had not been seen before because water vapor is transparent at most visible wavelengths of light. But Herschel could see the cloud with its infrared detectors. "Herschel is providing dramatic new information about everything from planets in our own solar system to galaxies billions of light-years away,” said Paul Goldsmith, the NASA Herschel project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The discovery of the torus around Saturn did not come as a complete surprise. NASA’s Voyager and Hubble missions had given scientists hints of the existence of water-bearing clouds around Saturn. Then in 1997, the European Space Agency’s Infrared Space Observatory confirmed the presence of water in Saturn’s upper atmosphere. NASA’s Submillimeter Wave Astronomy Satellite also observed water emission from Saturn at far-infrared wavelengths in 1999.

While a small amount of gaseous water is locked in the warm, lower layers of Saturn’s atmosphere, it can’t rise to the colder, higher levels. To get to the upper atmosphere, water molecules must be entering Saturn’s atmosphere from somewhere in space. But from where and how? Those were mysteries until now.

Build the model and the data will come.

The answer came by combining Herschel’s observations of the giant cloud of water vapor created by Enceladus’ plumes with computer models that researchers had already been developing to describe the behavior of water molecules in clouds around Saturn.

One of these researchers is Tim Cassidy, a recent post-doctoral researcher at JPL who is now at the University of Colorado’s Laboratory for Atmospheric and Space Physics, Boulder. “What’s amazing is that the model,” said Cassidy, “which is one iteration in a long line of cloud models, was built without knowledge of the observation. Those of us in this small modeling community were using data from Cassini, Voyager and the Hubble telescope, along with established physics. We weren’t expecting such detailed ‘images’ of the torus, and the match between model and data was a wonderful surprise.”

The results show that, though most of the water in the torus is lost to space, some of the water molecules fall and freeze on Saturn’s rings, while a small amount -- about 3 to 5 percent -- gets through the rings to Saturn’s atmosphere. This is just enough to account for the water that has been observed there.

Source:

Cassini Presents Saturn Moon Quintet

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 .

Next Stop: Jupiter

We were reminded today, in dramatic fashion, that NASA is still open for business and leading the world in space exploration. At 12:25 p.m. EDT, we launched the Juno spacecraft from the Space Coast of Florida on its five-year journey to Jupiter, putting NASA on a mission to yet another new frontier. Our future in space exploration is bright and holds many such cutting-edge science missions that will help us better understand our solar system and an ever-increasing array of challenging destinations where humans might travel.

Juno will speed past our moon in less than a single day before it begins its trek of 1,740 million miles to reach the largest planet in our solar system. Those astounding distances and speeds are hard for us to fathom, but they are the kind of numbers our dedicated scientists and navigators work with every day to get the job done.

Juno will orbit Jupiter's poles 33 times. Its color camera will provide unprecedented close-up images of the planet, including the first detailed glimpse of the planet's poles. Juno's eight science instruments will peer through our mysterious neighbor's atmosphere and tell us more about what goes on in its atmosphere and magnetosphere. They'll also help us determine if there is a solid core to this gas giant.

Juno will power its systems using solar energy. This is the farthest out we've yet sent a spacecraft using this type of energy source. It's just one of many things we'll be looking at as we make the most of the spacecraft's journey to help refine technology for future exploration missions.

Source:

NASA Announces Design for New Deep Space Exploration System

NASA is ready to move forward with the development of the Space Launch System -- an advanced heavy-lift launch vehicle that will provide an entirely new national capability for human exploration beyond Earth's orbit. The Space Launch System will give the nation a safe, affordable and sustainable means of reaching beyond our current limits and opening up new discoveries from the unique vantage point of space.

The Space Launch System, or SLS, will be designed to carry the Orion Multi-Purpose Crew Vehicle, as well as important cargo, equipment and science experiments to Earth's orbit and destinations beyond. Additionally, the SLS will serve as a back up for commercial and international partner transportation services to the International Space Station.

"This launch system will create good-paying American jobs, ensure continued U.S. leadership in space, and inspire millions around the world," NASA Administrator Charles Bolden said. "President Obama challenged us to be bold and dream big, and that's exactly what we are doing at NASA. While I was proud to fly on the space shuttle, tomorrow's explorers will now dream of one day walking on Mars."

The SLS rocket will incorporate technological investments from the Space Shuttle Program and the Constellation Program in order to take advantage of proven hardware and cutting-edge tooling and manufacturing technology that will significantly reduce development and operations costs. It will use a liquid hydrogen and liquid oxygen propulsion system, which will include the RS-25D/E from the Space Shuttle Program for the core stage and the J-2X engine for the upper stage. SLS will also use solid rocket boosters for the initial development flights, while follow-on boosters will be competed based on performance requirements and affordability considerations. The SLS will have an initial lift capacity of 70 metric tons. That's more than 154,000 pounds, or 77 tons, roughly the weight of 40 sport utility vehicles. The lift capacity will be evolvable to 130 metric tons -- more than 286,000 pounds, or 143 tons -- enough to lift 75 SUVs. The first developmental flight, or mission, is targeted for the end of 2017.

This specific architecture was selected, largely because it utilizes an evolvable development approach, which allows NASA to address high-cost development activities early on in the program and take advantage of higher buying power before inflation erodes the available funding of a fixed budget. This architecture also enables NASA to leverage existing capabilities and lower development costs by using liquid hydrogen and liquid oxygen for both the core and upper stages. Additionally, this architecture provides a modular launch vehicle that can be configured for specific mission needs using a variation of common elements. NASA may not need to lift 130 metric tons for each mission and the flexibility of this modular architecture allows the agency to use different core stage, upper stage, and first-stage booster combinations to achieve the most efficient launch vehicle for the desired mission.

Source: Nasa

NASA's Dawn Collects a Bounty of Beauty from Vesta

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.

NASA Mars Research Helps Find Buried Water on Earth

A NASA-led team has used radar sounding technology developed to explore the subsurface of Mars to create high-resolution maps of freshwater aquifers buried deep beneath an Earth desert, in the first use of airborne sounding radar for aquifer mapping.

The research may help scientists better locate and map Earth's desert aquifers, understand current and past hydrological conditions in Earth's deserts and assess how climate change is impacting them. Deserts cover roughly 20 percent of Earth's land surface, including highly populated regions in the Arabian Peninsula, North Africa, west and central Asia and the southwestern United States.

An international team led by research scientist Essam Heggy of NASA's Jet Propulsion Laboratory, Pasadena, Calif., recently traveled to northern Kuwait to map the depth and extent of aquifers in arid environments using an airborne sounding radar prototype. The 40-megahertz, low-frequency sounding radar was provided by the California Institute of Technology in Pasadena; and the Institut de Physique du Globe de Paris, France. Heggy's team was joined by personnel from the Kuwait Institute for Scientific Research (KISR), Kuwait City.

For two weeks, the team flew a helicopter equipped with the radar on 12 low-altitude passes (1,000 feet, or 305 meters) over two well-known freshwater aquifers, probing the desert subsurface down to the water table at depths ranging from 66 to 213 feet (20 to 65 meters). The researchers successfully demonstrated that the radar could locate subsurface aquifers, probe variations in the depth of the water table, and identify locations where water flowed into and out of the aquifers.

"This demonstration is a critical first step that will hopefully lead to large-scale mapping of aquifers, not only improving our ability to quantify groundwater processes, but also helping water managers drill more accurately," said Muhammad Al-Rashed, director of KISR's Division of Water Resources.

The radar is sensitive to changes in electrical characteristics of subsurface rock, sediments and water- saturated soils. Water-saturated zones are highly reflective and mirror the low-frequency radar signal. The returned radar echoes explored the thick mixture of gravel, sand and silt that covers most of Kuwait's northern desert and lies above its water table.

The team created high-resolution cross sections of the subsurface, showing variations in the fresh groundwater table in the two aquifers studied. The radar results were validated with ground measurements performed by KISR.

"This research will help scientists better understand Earth's fossil aquifer systems, the approximate number, occurrence and distribution of which remain largely unknown," said Heggy. "Much of the evidence for climate change in Earth's deserts lies beneath the surface and is reflected in its groundwater. By mapping desert aquifers with this technology, we can detect layers deposited by ancient geological processes and trace back paleoclimatic conditions that existed thousands of years ago, when many of today's deserts were wet."

Heggy said most recent observations, scientific interest and data analyses of global warming have concentrated on Earth's polar regions and forests, which provide direct measurable evidence of large-scale environmental changes. Arid and semi-arid environments, which represent a substantial portion of Earth's surface, have remained poorly studied. Yet water scarcity and salt content, changes in rainfall, flash floods, high rates of aquifer exploitation and growth of desert regions are all signs that suggest climate change and human activities are also affecting these arid and semi-arid zones.

The radar sounding prototype shares similar characteristics with two instruments flying on Mars-orbiting spacecraft: Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), on the European Space Agency's Mars Express, and Shallow Radar (SHARAD), on NASA's Mars Reconnaissance Orbiter. MARSIS, jointly developed by JPL and the Italian Space Agency, probes the Martian subsurface sediments and polar ice caps to a maximum depth of about 1.9 miles (3 kilometers). SHARAD, also built by the Italian Space Agency, looks for liquid or frozen water in the first few hundred feet of Mars' crust and probes Mars' polar caps. Both instruments have found evidence of ice in the Martian subsurface, but have not yet detected liquid water. The Kuwait results may lead to revised interpretations of data from these two instruments.

The research follows earlier work by JPL scientists to probe the subsurface of the Sahara desert using higher-frequency Synthetic Aperture Radar instruments flown onboard three space shuttle missions in 1981, 1984 and 1994. That work located shallow drainage networks and large dry basins, suggesting the Sahara has had extensive surface water activity in its recent geological past.
Kuwait's well-mapped shallow aquifers and flat surface provided the team with an ideal test location. Extreme dryness, such as that present in this region of Kuwait, is necessary to allow the radar's waves to penetrate deep into the surface and reflect on water-saturated layers beneath. Kuwait's flat topography and low radio noise also reduced clutter and improved the radar signal's return.

"Results of this study pave the way for potential airborne mapping of aquifers in hyper-arid regions such as the Sahara and Arabian Peninsula, and can be applied to design concepts for a possible future satellite mission to map Earth's desert aquifers," said Craig Dobson, program officer for Geodetic Imaging and Airborne Instrument Technology Transition programs at NASA Headquarters, Washington. The work is a pathfinder for the Orbiting Arid Subsurface and Ice Sheet Sounder (OASIS), a NASA spacecraft mission concept designed to map shallow aquifers in Earth's most arid desert regions and measure ice sheet volume, thickness, basal topography and discharge rates.

The study was co-funded by the California Institute of Technology's Keck Institute for Space Studies and KISR. The Kuwaiti Police Air Force provided technical support for the flight tests.

NASA Gives Public New Internet Tool to Explore the Solar System

NASA is giving the public the power to journey through the solar system using a new interactive Web-based tool.

The "Eyes on the Solar System" interface combines video game technology and NASA data to create an environment for users to ride along with agency spacecraft and explore the cosmos. Screen graphics and information such as planet locations and spacecraft maneuvers use actual space mission data.

"This is the first time the public has been able to see the entire solar system and our missions moving together in real time," said Jim Green, director of NASA's Planetary Science Division at the agency's Headquarters in Washington. "It demonstrates NASA's continued commitment to share our science with everyone."

The virtual environment uses the Unity game engine to display models of planets, moons, asteroids, comets and spacecraft as they move through our solar system. With keyboard and mouse controls, users cruise through space to explore anything that catches their interest. A free browser plug-in, available at the site, is required to run the Web application.

"You are now free to move about the solar system," said Blaine Baggett, executive manager in the Office of Communication and Education at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "See what NASA's spacecraft see -- and where they are right now -- all without leaving your computer."

Users may experience missions in real time, and "Eyes on the Solar System" also allows them to travel through time. The tool is populated with NASA data dating back to 1950 and projected to 2050.
The playback rate can be sped up or slowed down. When NASA's Juno spacecraft launched on Aug. 5, 2011, users could look ahead to see the mission's five-year journey to Jupiter in a matter of seconds.

Point of view can be switched from faraway to close-up to right "on board" spacecraft. Location, motion and appearance are based on predicted and reconstructed mission data. Dozens of controls on a series of pop-up menus allow users to fully customize what they see, and video and audio tutorials explain how to use the tool's many options. Users may choose from 2-D or 3-D modes, with the latter simply requiring a pair of red-cyan glasses to see.

"By basing our visualization primarily on mission data, this tool will help both NASA and the public better understand complex space science missions," said Kevin Hussey, manager of Visualization Technology Applications and Development at JPL, whose team developed "Eyes on the Solar System."

"Eyes on the Solar System" is in beta release. It has been demonstrated at science conferences, in classrooms and at the 2011 South by Southwest Interactive Conference in Austin, Texas.

Designers are updating "Eyes on the Solar System" to include NASA science missions launching during the coming months, including GRAIL to the moon and the Mars Science Laboratory Curiosity rover.

"Eyes on the Solar System" and an introduction video are available at http://solarsystem.nasa.gov/eyes .

Updates on new features are available through the tool's Twitter account: http://twitter.com/NASA_Eyes .

JPL is a division of the California Institute of Technology in Pasadena.