NASA Video Shows Global Reach of Pollution from Fires

A series of large wildfires burning across western and central Russia, eastern Siberia and western Canada has created a noxious soup of air pollution that is affecting life far beyond national borders. Among the pollutants created by wildfires is carbon monoxide, a gas that can pose a variety of health risks at ground level. Carbon monoxide is also an ingredient in the production of ground-level ozone, which causes numerous respiratory problems. As the carbon monoxide from these wildfires is lofted into the atmosphere, it becomes caught in the lower bounds of the mid-latitude jet stream, which swiftly transports it around the globe.

Two movies were created using continuously updated data from the "Eyes on the Earth 3-D" feature on NASA's global climate change website http://climate.nasa.gov/ . They show three-day running averages of daily measurements of carbon monoxide present at an altitude of 5.5 kilometers (18,000) feet, along with its global transport. The data are from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft. AIRS is most sensitive to carbon monoxide at this altitude, which is a region conducive to long-range transport of the smoke. The abundance of carbon monoxide is shown in parts per billion, with the highest concentrations shown in yellows and reds.

The first movie, centered over Moscow, highlights the series of wildfires that continue to burn across Russia. It covers the period between July 18 and Aug. 10, 2010.

The second movie is centered over the North Pole and covers the period from July 16 to Aug. 10, 2010. From this vantage point, the long-range transport of pollutants is more easily visible.

AIRS is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

More information about AIRS can be found at http://airs.jpl.nasa.gov .

For more information visit http://www.nasa.gov/topics/earth/features/earth20100811.html

Cassini Bags Enceladus 'Tigers'

NASA's Cassini spacecraft has successfully completed its flyby over the "tiger stripes" in the south polar region of Saturn's moon Enceladus and has sent back images of its passage. The spacecraft also targeted the moon Tethys.

The tiger stripes are actually giant fissures that spew jets of water vapor and organic particles hundreds of kilometers, or miles, out into space. While the winter is darkening the moon's southern hemisphere, Cassini has its own version of "night vision goggles" -- the composite infrared spectrometer instrument - to track heat even when visible light is low. It will take time for scientists to assemble the data into temperature maps of the fissures.

The camera was pointing toward Enceladus at approximately 348,913 kilometers (216,805 miles) away, and the image was taken using the CL1 and GRN filters. This image has not been validated or calibrated. A validated/calibrated image will be archived with the NASA Planetary Data System in 2011. Image Credit: NASA/JPL/Space Science Institute

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 in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

More raw images from the Enceladus flyby, dubbed "E11," are available at: http://saturn.jpl.nasa.gov/photos/raw/

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

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100814.html

NASA Instrument Tracks Pollution from Russian Fires

Drought and the worst heat wave Russia has seen in 130 years have sparked a devastating outbreak of wildfires across the nation this summer, primarily in the country's western and central regions. According to wire service reports and Russia's Emergency Situations Ministry, as of Aug. 6, 2010, some 558 fires were burning. The fires have killed at least 52 people, destroyed some 2,000 homes and charred more than 1,796 square kilometers (693 square miles). Russia's capital city of Moscow is currently blanketed in a thick smog, which has curtailed activities and disrupted air traffic. According to the Associated Press, levels of carbon monoxide pollution in Moscow are at an all-time high, four times higher than normal.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft is tracking the concentration and transport of carbon monoxide from the Russian fires. The figures presented here show the abundance of carbon monoxide present in the atmosphere at an altitude of 5.5 kilometers (18,000 feet). AIRS is sensitive to carbon monoxide in the mid-troposphere at heights between 2 and 10 kilometers (1.2 and 6.2 miles), with a peak sensitivity at an altitude of approximately 5 kilometers (3.1 miles). This region of Earth's atmosphere is also conducive to the long-range transport of the pollution that is lofted to this altitude.

Top (fig.1) and bottom (fig.2) comparison of carbon monoxide pollution from the series of devastating wildfires burning across central and western Russia, as seen by the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft on July 21, 2010 (top) and Aug. 1, 2010 (bottom). The AIRS data show the abundance of carbon monoxide present in the atmosphere at an altitude of 5.5 kilometers (18,000 feet). Image credit: NASA/JPL/Leonid Yurganov, University of Maryland, Baltimore County

As shown in Figure 1, acquired July 21, 2010, the concentration of carbon monoxide from the fires on that date was largely limited to the European part of Russia (western and central Russia). This contrasts dramatically with the data in Figure 2, acquired on August 1, when the carbon monoxide concentration was much higher and the area of the fires had increased significantly. The concentration of carbon monoxide is continuing to grow. According to Aug. 4 NASA estimates, the smoke plume from the fires spans about 3,000 kilometers (1,860 miles) from east to west, approximately the distance from San Francisco to Chicago.

Fig. 3 - Changes in the total amount of carbon monoxide above western Russia, in megatons, through Aug. 1, 2010, as measured by the JPL AIRS instrument on NASA's Aqua spacecraft, are compared with 2002 data from the MOPITT instrument on NASA's Terra spacecraft and data from the year 2009, which saw normal levels of seasonal carbon monoxide. Image credit: NASA/JPL/Leonid Yurganov, University of Maryland, Baltimore County

Figure 3 shows changes in the total amount of carbon monoxide above western Russia in megatons through August 1, 2010 (shown by the red curve). The changes are plotted again the base year of 2009, which saw normal levels of seasonal carbon monoxide. This is contrasted against the year 2002, when peat fires predominated in Russia. The 2002 data are from the Measurements of Pollution in the Troposphere (MOPITT) instrument on NASA's Terra spacecraft. On August 1, 2010, the excess carbon monoxide content almost reached the maximum values seen in 2002. The rate of growth (approximately 0.7 megatons, or 700,000 metric tons, per day) characterizes the rate of emission; the current rate is approximately three times higher than in 2002.

AIRS is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena. More information about AIRS can be found at http://airs.jpl.nasa.gov.

For more information visit http://www.nasa.gov/topics/earth/features/fires20100806.html

Blowing in the Wind: Cassini Helps with Dune Whodunit

The answer to the mystery of dune patterns on Saturn's moon Titan did turn out to be blowing in the wind. It just wasn't from the direction many scientists expected.

Basic principles describing the rotation of planetary atmospheres and data from the European Space Agency's Huygens probe led to circulation models that showed surface winds streaming generally east-to-west around Titan's equatorial belt. But when NASA's Cassini spacecraft obtained the first images of dunes on Titan in 2005, the dunes' orientation suggested the sands – and therefore the winds – were moving from the opposite direction, or west to east.

A new paper by Tetsuya Tokano in press with the journal Aeolian Research seeks to explain the paradox. It explains that seasonal changes appear to reverse wind patterns on Titan for a short period. These gusts, which occur intermittently for perhaps two years, sweep west to east and are so strong they do a better job of transporting sand than the usual east-to-west surface winds. Those east-to-west winds do not appear to gather enough strength to move significant amounts of sand.

A related perspective article about Tokano's work by Cassini radar scientist Ralph Lorenz, the lead author on a 2009 paper mapping the dunes, appears in this week's issue of the journal Science.

"It was hard to believe that there would be permanent west-to-east winds, as suggested by the dune appearance," said Tokano, of the University of Cologne, Germany. "The dramatic, monsoon-type wind reversal around equinox turns out to be the key."

Cassini radar sees sand dunes on Saturn's giant moon Titan (upper photo) that are sculpted like Namibian sand dunes on Earth (lower photo). The bright features in the upper radar photo are not clouds but topographic features among the dunes. Image credit: NASA/JPL - upper photo; NASA/JSC - lower photo

The dunes track across the vast sand seas of Titan only in latitudes within 30 degrees of the equator. They are about a kilometer (half a mile) wide and tens to hundreds of kilometers (miles) long. They can rise more than 100 meters (300 feet) high. The sands that make up the dunes appear to be made of organic, hydrocarbon particles. The dunes' ridges generally run west-to-east, as wind here generally sheds sand along lines parallel to the equator.

Scientists predicted winds in the low latitudes around Titan's equator would blow east-to-west because at higher latitudes the average wind blows west-to-east. The wind forces should balance out, based on basic principles of rotating atmospheres.

Tokano re-analyzed a computer-based global circulation model for Titan he put together in 2008. That model, like others for Titan, was adapted from ones developed for Earth and Mars. Tokano added in new data on Titan topography and shape based on Cassini radar and gravity data. In his new analysis, Tokano also looked more closely at variations in the wind at different points in time rather than the averages. Equinox periods jumped out.

Equinoxes occur twice a Titan year, which is about 29 Earth years. During equinox, the sun shines directly over the equator, and heat from the sun creates upwelling in the atmosphere. The turbulent mixing causes the winds to reverse and accelerate. On Earth, this rare kind of wind reversal happens over the Indian Ocean in transitional seasons between monsoons.

The episodic reverse winds on Titan appear to blow around 1 to 1.8 meters per second (2 to 4 mph). The threshold for sand movement appears to be about 1 meter per second (2 mph), a speed that the typical east-to-west winds never appear to surpass. Dune patterns sculpted by strong, short episodes of wind can be found on Earth in the northern Namib sand seas in Namibia, Africa.

Scientists have used data from the Cassini radar mapper to map the global wind pattern on Saturn's moon Titan using data collected over a four-year period, as depicted in this image. Image credit: NASA/JPL/Space Science Institute

"This is a subtle discovery -- only by delving into the statistics of the winds in the model could this rather distressing paradox be resolved," said Ralph Lorenz, a Cassini radar scientist based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "This work is also reassuring for preparations for proposed future missions to Titan, in that we can become more confident in predicting the winds which can affect the delivery accuracy of landers, or the drift of balloons."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. JPL is a division of the California Institute of Technology in Pasadena.

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100729.html

NASA's ATHLETE Warms Up for High Desert Run

Engineers from NASA's Jet Propulsion Laboratory are currently putting their All-Terrain, Hex-Limbed, Extra-Terrestrial Explorer (ATHLETE) through a series of long-drive tests on the long, dirt roads found adjacent to JPL. The JPL grounds do not include an unpaved area of sufficient size for testing such a large robot over a long distance. Some of the dirt roads in the Arroyo Seco (a wash located next to JPL) are wide enough for ATHLETE, and its close proximity to JPL allows the robot to be secured in its hangar between test runs.

The engineers want to test the moon rover's ability to meet a NASA milestone of traveling at least 40 kilometers (25 miles) over 14 days under its own power. The official demonstration is slated to begin in the Arizona high desert next month.

Engineers test the ATHLETE moon rover on one of the long dirt roads found just outside JPL. Image credit: NASA

ATHLETE is a 1/2-scale working prototype of a robot under development to transport habitats and other cargo on the surface of the Moon or Mars. The ATHLETE concept is a level cargo deck carried by six wheels, each on the end of a configurable leg. The prototype stands approximately 4.5 meters (15 feet) tall and 4.5 meters (15 ft) wide and weighs about (about 2,300 kilograms (2.5 tons). The robot moves relatively slowly, with a top speed during traverse of approximately 2 kilometers per hour (1.25 mph).

For more information about ATHLETE, including photos and video clips, visit: http://athlete.jpl.nasa.gov/.

It takes a lot of hard work, ingenuity and creativity to build a rover like ATHLETE. And it takes a lot of creativity of a different sort to make ATHLETE "dance." See the results of that effort in a fast-action video of ATHLETE bustin' a move.

For more information visit http://www.nasa.gov/topics/moonmars/features/athlete20100730.html

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NASA Spacecraft Camera Yields Most Accurate Mars Map Ever

PASADENA, Calif. -- A camera aboard NASA's Mars Odyssey spacecraft has helped develop the most accurate global Martian map ever. Researchers and the public can access the map via several websites and explore and survey the entire surface of the Red Planet.

The map was constructed using nearly 21,000 images from the Thermal Emission Imaging System, or THEMIS, a multi-band infrared camera on Odyssey. Researchers at Arizona State University's Mars Space Flight Facility in Tempe, in collaboration with NASA's Jet Propulsion Laboratory in Pasadena, Calif., have been compiling the map since THEMIS observations began eight years ago.

The pictures have been smoothed, matched, blended and cartographically controlled to make a giant mosaic. Users can pan around images and zoom into them. At full zoom, the smallest surface details are 100 meters (330 feet) wide. While portions of Mars have been mapped at higher resolution, this map provides the most accurate view so far of the entire planet.

The new map is available at: http://www.mars.asu.edu/maps/?layer=thm_dayir_100m_v11 .

Advanced users with large bandwidth, powerful computers and software capable of handling images in the gigabyte range can download the full-resolution map in sections at: http://www.mars.asu.edu/data/thm_dir_100m .

Valles Marineris, the "Grand Canyon of Mars," sprawls wide enough to reach from Los Angeles to nearly New York City, if it were located on Earth. The red outline box shows the location of a second, full-resolution image. Credit: NASA/JPL/Arizona State University

"We've tied the images to the cartographic control grid provided by the U.S. Geological Survey, which also modeled the THEMIS camera's optics," said Philip Christensen, principal investigator for THEMIS and director of the Mars Space Flight Facility. "This approach lets us remove all instrument distortion, so features on the ground are correctly located to within a few pixels and provide the best global map of Mars to date."

Working with THEMIS images from the new map, the public can contribute to Mars exploration by aligning the images to within a pixel's accuracy at NASA's "Be a Martian" website, which was developed in cooperation with Microsoft Corp. Users can visit the site at: http://beamartian.jpl.nasa.gov/maproom#/MapMars .

"The Mars Odyssey THEMIS team has assembled a spectacular product that will be the base map for Mars researchers for many years to come," said Jeffrey Plaut, Odyssey project scientist at JPL. "The map lays the framework for global studies of properties such as the mineral composition and physical nature of the surface materials."

Other sites build upon the base map. At Mars Image Explorer, which includes images from every Mars orbital mission since the mid-1970s, users can search for images using a map of Mars at: http://themis.asu.edu/maps .

"The broad purpose underlying all these sites is to make Mars exploration easy and engaging for everyone," Christensen said. "We are trying to create a user-friendly interface between the public and NASA's Planetary Data System, which does a terrific job of collecting, validating and archiving data."

This image shows a 90-mile-wide portion of the giant Valles Marineris canyon system. Landslide debris and gullies in the canyon walls on Mars can be seen at 100 meters (330 feet) per pixel. Credit: NASA/JPL/Arizona State University

Mars Odyssey was launched in April 2001 and reached the Red Planet in October 2001. Science operations began in February 2002. The mission is managed by JPL for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver is the prime contractor for the project and built the spacecraft. NASA's Planetary Data System, sponsored by the Science Mission Directorate, archives and distributes scientific data from the agency's planetary missions, astronomical observations, and laboratory measurements.

For more information about NASA's Odyssey spacecraft, visit: http://mars.jpl.nasa.gov/odyssey .

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

For more information visit http://www.nasa.gov/mission_pages/odyssey/odyssey20100723.html

See Beautiful Ontario Lacus: Cassini's Guided Tour

Ontario Lacus, the largest lake in the southern hemisphere of Saturn's moon Titan, turns out to be a perfect exotic vacation spot, provided you can handle the frosty, subzero temperatures and enjoy soaking in liquid hydrocarbon.

Several recent papers by scientists working with NASA's Cassini spacecraft describe evidence of beaches for sunbathing in Titan's low light, sheltered bays for mooring boats, and pretty deltas for wading out in the shallows. They also describe seasonal changes in the lake's size and depth, giving vacationers an opportunity to visit over and over without seeing the same lake twice. (Travel agents, of course, will have to help you figure out how to breathe in an atmosphere devoid of oxygen.)

Using data that give us the most detailed picture yet of a lake on another world, scientists and animators have collaborated on a new video tour of Ontario Lacus based on radar data from Cassini's Titan flybys on June 22, 2009, July 8, 2009, and Jan. 12, 2010. A Web video explaining how scientists look to Earth's Death Valley to understand places like Titan's Ontario Lacus is available at: http://www.nasa.gov/multimedia/videogallery/index.html?collection_id=14658&media_id=16290407

"With such frigid temperatures and meager sunlight, you wouldn't think Titan has a lot in common with our own Earth," said Steve Wall, deputy team lead for the Cassini radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "But Titan continues to surprise us with activity and seasonal processes that look marvelously, eerily familiar."

Cassini arrived at Saturn in 2004 when the southern hemisphere of the planet and its moons were experiencing summer. The seasons have started to change toward autumn, with winter solstice darkening the southern hemisphere of Titan in 2017. A year on Titan is the equivalent of about 29 Earth years.

This image of Ontario Lacus, the largest lake on the southern hemisphere of Saturn's moon Titan, was obtained by NASA's Cassini spacecraft on Jan. 12, 2010. Image Credit: NASA/JPL-Caltech

Titan is the only other world in our solar system known to have standing bodies of liquid on its surface. Because surface temperatures at the poles average a chilly 90 Kelvin (about minus 300 degrees Fahrenheit), the liquid is a combination of methane, ethane and propane, rather than water. Ontario Lacus has a surface area of about 15,000 square kilometers (6,000 square miles), slightly smaller than its terrestrial namesake Lake Ontario.

Cassini first obtained an image of Ontario Lacus with its imaging camera in 2004. A paper submitted to the journal Icarus by Alex Hayes, a Cassini radar team associate at the California Institute of Technology in Pasadena, and colleagues finds that the lake's shoreline has receded by about 10 kilometers (6 miles). This has resulted in a liquid level reduction of about 1 meter (3 feet) per year over a four–year period.

The shoreline appears to be receding because of liquid methane evaporating from the lake, with a total amount of evaporation that would significantly exceed the yearly methane gas output of all the cows on Earth, Hayes said. Some of the liquid could also seep into porous ground material. Hayes said the changes in the lake are likely occurring as part of Titan's seasonal methane cycle, and would be expected to reverse during southern winter.

This seasonal filling and receding is similar to what occurs at the shallow lakebed known as Racetrack Playa in Death Valley National Park, Hayes said. In fact, from the air, the topography and shape of Racetrack Playa and Ontario Lacus are quite similar, although Ontario Lacus is about 60 times larger.

"We are very excited about these results, because we did not expect Cassini to be able to detect changes of this magnitude in Titan's lakes," Hayes said. "It is only through the continued monitoring of seasonal variation during Cassini's extended mission that these discoveries have been made possible."

Other parts of the Ontario Lacus' shoreline, as described in the paper published in Geophysical Research Letters in March 2010 by Wall, Hayes and other colleagues, show flooded valleys and coasts, further proof that the lake level has changed.

The delta revealed by Cassini radar data on the western shore of Ontario Lacus is also the first well-developed delta observed on Titan, Wall said. He explained that the shape of the land there shows liquid flowing down from a higher plain switching channels on its way into the lake, forming at least two lobes.

Examples of this kind of channel switching and wave-modified deltas can be found on Earth at the southern end of Lake Albert between Uganda and the Democratic Republic of Congo in Africa, and the remains of an ancient lake known as Megachad in the African country Chad, Wall said.

The radar data also show a smooth beach on the northwestern shore of Ontario Lacus. Smooth lines parallel to the current shoreline could be formed by low waves over time, which were likely driven by winds sweeping in from the west or southwest. The pattern at Ontario Lacus resembles what might be seen on the southeastern side of Lake Michigan, where waves sculpt the shoreline in a similar fashion.

"Cassini continues to take our breath away as it fills in the details on the surfaces of these far-off moons," said Linda Spilker, Cassini project scientist based at JPL. "It's exhilarating to ride along as it takes us on the ultimate cold-weather adventure."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

More Cassini information is available, at http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov.

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100715.html

Giant Antenna Propped up and Ready for Joint Replacement

Workers at NASA's Deep Space Network complex in Goldstone, Calif., have been making precise, laser-assisted measurements to ensure a flat surface for pouring new grout as part of a major renovation on the 70-meter-wide (230-foot-wide) "Mars antenna." While officially dubbed Deep Space Station 14, the antenna picked up the Mars name from its first task: tracking NASA's Mariner 4 spacecraft, which had been lost by smaller antennas after its historic flyby of Mars.

This work represents the first time network engineers have redesigned and replaced the hydrostatic bearing assembly, which enables the antenna to rotate horizontally. To accomplish this, they lifted the entire rotating structure of the giant antenna for the first time.

The hydrostatic bearing assembly puts the weight of the antenna on three pads, which glide on a film of oil around a large steel ring. The ring measures about 24 meters (79 feet) in diameter and must be flat to work efficiently. After 44 years of near-constant use, the Mars antenna needed a kind of joint replacement, since the bearing assembly had become uneven.

As the sun sets on July 8, 2010, workers prepare to pour new epoxy grout for thehydrostatic bearing assembly of the giant "Mars antenna" at NASA's Deep Space Network communications site in Goldstone, Calif. Image credit: NASA/JPL-Caltech

Engineers and managers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., which manages the Deep Space Network for NASA, drew up plans for new runner segments, new sole plates below the runner segments, and an epoxy grout that is more impervious to oil. The thicker segments deform less when the antenna's pads pass over them, and allow for more tightly sealed joints.

Tim Sink, an engineer at NASA's Jet Propulsion Laboratory in Pasadena, Calif., checks the evenness of sole plates installed on the giant "Mars antenna" at the DSN site. Image credit: NASA/JPL-Caltech

Since beginning work in March, engineers and technicians have carefully lifted several million pounds of delicate scientific instruments about five millimeters (0.2 inches) and transferred the weight of the antenna to temporary supporting legs. They have removed the old steel runner and cement-based grout. They have also installed sole plates, which cover the grout and anchor the new runner. Over the past week, JPL engineers checked to make sure the sole plates were level, and workers poured the new epoxy grout underneath to hold them in place. Mixing and pouring the new grout occurred at night to ensure the work was completed within the tight temperature tolerances required to handle this material.

Over the next few weeks, the new, thicker steel runner segments will be installed. Work is on track to return the antenna to service on Nov. 1, 2010.

For more details about the work on the Mars antenna, visit: http://www.jpl.nasa.gov/news/news.cfm?release=2010-083

For more information about the Deep Space Network, visit: http://deepspace.jpl.nasa.gov/dsn
For more information about NASA's space communications and navigation program, visit: http://www.spacecomm.nasa.gov

For more information visit http://www.nasa.gov/topics/technology/features/dsn20100714.html

Voyager 2 at 12,000 Days: The Super-Marathon Continues

NASA's plucky Voyager 2 spacecraft has hit a long-haul operations milestone today (June 28) -- operating continuously for 12,000 days. For nearly 33 years, the venerable spacecraft has been returning data about the giant outer planets, and the characteristics and interaction of solar wind between and beyond the planets. Among its many findings, Voyager 2 discovered Neptune's Great Dark Spot and its 450-meter-per-second (1,000-mph) winds.

The two Voyager spacecraft have been the longest continuously operating spacecraft in deep space. Voyager 2 launched on August 20, 1977, when Jimmy Carter was president. Voyager 1 launched about two weeks later on Sept. 5. The two spacecraft are the most distant human-made objects, out at the edge of the heliosphere -- the bubble the sun creates around the solar system. Mission managers expect Voyager 1 to leave our solar system and enter interstellar space in the next five years or so, with Voyager 2 on track to enter interstellar space shortly after that.

This artist's rendering depicts NASAs Voyager 2 spacecraft as it studies the outer limits of the heliosphere - a magnetic 'bubble' around the solar system that is created by the solar wind. Image credit: NASA/JPL-Caltech.

Having traveled more than 21 billion kilometers (13 billion miles) on its winding path through the planets toward interstellar space, the spacecraft is now nearly 14 billion kilometers (9 billion miles) from the sun. A signal from the ground, traveling at the speed of light, takes about 12.8 hours one-way to reach Voyager 2.

This image of the official Voyager clock, taken today, June 28, 2010, at NASA's Jet Propulsion Laboratory, shows that NASA's Voyager 2 spacecraft has been operating continuously for 12,000 days. The Voyager clock is kept at JPL. Image Credit: NASA/JPL-Caltech.

Voyager 1 will reach this 12,000-day milestone on July 13, 2010 after traveling more than 22 billion kilometers (14 billion miles). Voyager 1 is currently more than 17 billion kilometers (11 billion miles) from the sun.

The Voyagers were built by JPL, which continues to operate both spacecraft. Caltech manages JPL for NASA.

For more information about the Voyagers, visit: http://voyager.jpl.nasa.gov/.

For more information visit http://www.nasa.gov/mission_pages/voyager/voyager20100628.html

Earth to Lend Helping Hand to Comet Craft

NASA's Deep Impact/EPOXI spacecraft will fly past Earth this Sunday (June 27). Mission navigators have tailored this trajectory so the spacecraft can "hitch a ride" on Earth's gravity field, which will help propel the mission toward its appointment with comet Hartley 2 this fall. At time of closest approach to Earth, the spacecraft will be about 30,400 kilometers (18,900 miles) above the South Atlantic.

"Earth is a great place to pick up orbital velocity," said Tim Larson, the EPOXI project manager from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This flyby will give our spacecraft a 1.5-kilometer-per-second [3,470 mph] boost, setting us up to get up close and personal with comet Hartley 2."

EPOXI is an extended mission of the Deep Impact spacecraft. Its name is derived from its two tasked science investigations -- the Deep Impact Extended Investigation (DIXI) and the Extrasolar Planet Observation and Characterization (EPOCh). On Nov. 4, 2010, the mission will conduct an extended flyby of Hartley 2 using all three of the spacecraft's instruments (two telescopes with digital color cameras and an infrared spectrometer).

NASA's Deep Impact/EPOXI spacecraft, illustrated in this artist's concept, will fly past Earth on June 27, 2010. The spacecraft has an appointment with comet Hartley 2 this fall. Image credit: NASA/JPL-Caltech

The University of Maryland is the Principal Investigator institution. JPL manages EPOXI for NASA's Science Mission Directorate, Washington. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For information about EPOXI, visit http://www.nasa.gov/epoxi or http://epoxi.umd.edu/.

For more information visit http://www.nasa.gov/mission_pages/epoxi/epoxi20100625.html

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The Coolest Stars Come Out of the Dark

Astronomers have uncovered what appear to be 14 of the coldest stars known in our universe. These failed stars, called brown dwarfs, are so cold and faint that they'd be impossible to see with current visible-light telescopes. Spitzer's infrared vision was able to pick out their feeble glow, much as a firefighter uses infrared goggles to find hot spots buried underneath a dark forest floor.

The brown dwarfs join only a handful of similar objects previously discovered. The new objects are between the temperatures of about 450 Kelvin to 600 Kelvin (350 to 620 degrees Fahrenheit). As far as stars go, this is bitter cold -- as cold, in some cases, as planets around other stars.

These cool orbs have remained elusive for years, but will soon start coming out of the dark in droves. NASA's Wide-field Infrared Survey Explorer (WISE) mission, which is up scanning the entire sky now in infrared wavelengths, is expected to find hundreds of objects of a similarly chilly disposition, if not even colder. WISE is searching a volume of space 40 times larger than that sampled in the recent Spitzer study, which concentrated on a region in the constellation Boötes. The Spitzer mission is designed to look at targeted patches of sky in detail, while WISE is combing the whole sky.

"WISE is looking everywhere, so the coolest brown dwarfs are going to pop up all around us," said Peter Eisenhardt, the WISE project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and lead author of a recent paper in the Astronomical Journal on the Spitzer discoveries. "We might even find a cool brown dwarf that is closer to us than Proxima Centauri, the closest known star."

This artist's conception shows simulated data predicting the hundreds of failed stars, or brown dwarfs, that NASA's Wide-field Infrared Survey Explorer (WISE) is expected to add to the population of known stars in our solar neighborhood. Image credit: AMNH/UCB/NASA/JPL-Caltech

Brown dwarfs form like stars out of collapsing balls of gas and dust, but they are puny in comparison, never collecting enough mass to ignite nuclear fusion and shine with starlight. The smallest known brown dwarfs are about 5 to 10 times the mass of our planet Jupiter -- that's as massive as some known gas-giant planets around other stars. Brown dwarfs start out with a bit of internal heat left over from their formation, but with age, they cool down. The first confirmed brown dwarf was announced in 1995.

"Brown dwarfs are like planets in some ways, but they are in isolation," said astronomer Daniel Stern, co-author of the Spitzer paper at JPL. "This makes them exciting for astronomers -- they are the perfect laboratories to study bodies with planetary masses."

Most of the new brown dwarfs found by Spitzer are thought to belong to the coolest known class of brown dwarfs, called T dwarfs, which are defined as being less than about 1,500 Kelvin (2,240 degrees Fahrenheit). One of the objects appears to be so cold that it may even be a long-sought Y dwarf -- a proposed class of even colder stars. The T and Y classes are part of a larger system categorizing all stars; for example, the hottest, most massive stars are O stars; our sun is a G star.

"Models indicate there may be an entirely new class of stars out there, the Y dwarfs, that we haven't found yet," said co-author Davy Kirkpatrick, a co-author of the study and a member of the WISE science team at the California Institute of Technology, Pasadena, Calif. "If these elusive objects do exist, WISE will find them." Kirkpatrick is a world expert in brown dwarfs -- he came up with L, T and Y classifications for the cooler stars.

Kirkpatrick says that it's possible that WISE could find an icy, Neptune-sized or bigger object in the far reaches of our solar system -- thousands of times farther from the sun than Earth. There is some speculation amongst scientists that such a cool body, if it exists, could be a brown dwarf companion to our sun. This hypothetical object has been nicknamed "Nemesis."

"We are now calling the hypothetical brown dwarf Tyche instead, after the benevolent counterpart to Nemesis," said Kirkpatrick. "Although there is only limited evidence to suggest a large body in a wide, stable orbit around the sun, WISE should be able to find it, or rule it out altogether."

This image shows what astronomers think is one of the coldest brown dwarfs discovered so far (red dot in middle of frame). Image credit: NASA/JPL-Caltech

The 14 objects found by Spitzer are hundreds of light-years away -- too far away and faint for ground-based telescopes to see and confirm with a method called spectroscopy. But their presence implies that there are a hundred or more within only 25 light-years of our sun. Because WISE is looking everywhere, it will find these missing orbs, which will be close enough to confirm with spectroscopy. It's possible that WISE will even find more brown dwarfs within 25-light years of the sun than the number of stars known to exist in this space.

"WISE is going to transform our view of the solar neighborhood," said Eisenhardt. We'll be studying these new neighbors in minute detail -- they may contain the nearest planetary system to our own."

Other authors of the Spitzer paper are Roger Griffith and Amy Mainzer of JPL; Ned Wright, A.M. Ghez and Quinn Konopacky of UCLA; Matthew Ashby and Mark Brodwin of the Harvard-Smithsonian Center for Astrophysics, Cambridge; Mass., Michael Brown of Monash University, Australia; R.S. Bussmann of the University of Arizona, Tucson; Arjun Dey of National Optical Astronomy Observatory, Tucson, Ariz.; Eilat Glikman of Caltech; Anthony Gonzalez and David Vollbach of the University of Florida, Gainesville; and Shelley Wright of the University of California, Berkeley.

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.

JPL manages 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.

For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer. More information about WISE is online at http://wise.astro.ucla.edu and http://www.nasa.gov/wise.

For more information visit http://www.nasa.gov/mission_pages/spitzer/news/spitzer20100624.html

NASA Radar Images Show How Mexico Quake Deformed Earth

PASADENA, Calif. -- NASA has released the first-ever airborne radar images of the deformation in Earth's surface caused by a major earthquake -- the magnitude 7.2 temblor that rocked Mexico's state of Baja California and parts of the American Southwest on April 4.

The data reveal that in the area studied, the quake moved the Calexico, Calif., region in a downward and southerly direction up to 80 centimeters (31 inches). The maps can be seen at: http://www.nasa.gov/topics/earth/features/UAVSARimage20100623.html .

A science team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., used the JPL-developed Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) to measure surface deformation from the quake. The radar flies at an altitude of 12.5 kilometers (41,000 feet) on a Gulfstream-III aircraft from NASA's Dryden Flight Research Center, Edwards, Calif.

Fig. 1 - Overview of the UAVSAR interferogram of the magnitude 7.2 Baja California earthquake of April 4, 2010, overlaid atop a Google Earth image of the region. Major fault systems are shown by red lines, while recent aftershocks are denoted by yellow, orange and red dots. Image credit: NASA/JPL/USGS/Google

The team used a technique that detects minute changes in the distance between the aircraft and the ground over repeated, GPS-guided flights. The team combined data from flights on Oct. 21, 2009, and April 13, 2010. The resulting maps are called interferograms.

The April 4, 2010, El Mayor-Cucapah quake was centered 52 kilometers (32 miles) south-southeast of Calexico, Calif., in northern Baja California. It occurred along a geologically complex segment of the boundary between the North American and Pacific tectonic plates. The quake, the region's largest in nearly 120 years, was also felt in southern California and parts of Nevada and Arizona. It killed two, injured hundreds and caused substantial damage. There have been thousands of aftershocks, extending from near the northern tip of the Gulf of California to a few miles northwest of the U.S. border. The area northwest of the main rupture, along the trend of California's Elsinore fault, has been especially active, and was the site of a large, magnitude 5.7 aftershock on June 14.

UAVSAR has mapped California's San Andreas and other faults along the plate boundary from north of San Francisco to the Mexican border every six months since spring 2009, looking for ground motion and increased strain along faults. "The goal of the ongoing study is to understand the relative hazard of the San Andreas and faults to its west like the Elsinore and San Jacinto faults, and capture ground displacements from larger quakes," said JPL geophysicist Andrea Donnellan, principal investigator of the UAVSAR project to map and assess seismic hazard in Southern California.

Fig. 2 - Full-resolution portion of the portion of the UAVSAR interferogram where the largest deformation (up to 80 centimeters, or 31 inches) was measured. Image credit: NASA/JPL

Each UAVSAR flight serves as a baseline for subsequent quake activity. The team estimates displacement for each region, with the goal of determining how strain is partitioned between faults. When quakes do occur during the project, the team will observe their associated ground motions and assess how they may redistribute strain to other nearby faults, potentially priming them to break. Data from the Baja quake are being integrated into JPL's QuakeSim advanced computer models to better understand the fault systems that ruptured and potential impacts to nearby faults, such as the San Andreas, Elsinore and San Jacinto faults.

One figure (Figure 1) shows a UAVSAR interferogram swath measuring 110 by 20 kilometers (69 by 12.5 miles) overlaid atop a Google Earth image. Each colored contour, or fringe, of the interferogram represents 11.9 centimeters (4.7 inches) of surface displacement. Major fault lines are marked in red, and recent aftershocks are denoted by yellow, orange and red dots.

The quake's maximum ground displacements of up to 3 meters (10 feet) actually occurred well south of where the UAVSAR measurements stop at the Mexican border. However, these displacements were measured by JPL geophysicist Eric Fielding using synthetic aperture radar interferometry from European and Japanese satellites and other satellite imagery, and by mapping teams on the ground.

Scientists are still working to determine the exact northwest extent of the main fault rupture, but it is clear it came within 10 kilometers (6 miles) of the UAVSAR swath, close to the point where the interferogram fringes converge. "Continued measurements of the region should tell us whether the main fault rupture has moved north over time," Donnellan said.

An enlargement of the interferogram is shown in another figure (Figure 2), focusing on the area where the largest deformation was measured. The enlargement, which covers an area measuring about 20 by 20 kilometers (12.5 by 12.5 miles), reveals many small "cuts," or discontinuities, in the fringes. These are caused by ground motions ranging from a centimeter to tens of centimeters (a few inches) on small faults. "Geologists are finding the exquisite details of the many small fault ruptures extremely interesting and valuable for understanding the faults that ruptured in the April 4th quake," said Fielding. Another figure, (Figure 3) shows a close-up of the region where the magnitude 5.7 aftershock struck.

Fig. 3 - Detail of the UAVSAR interferogram in the area of the June 14 magnitude 5.7 aftershock, showing major faults and recent aftershocks. Image credit: NASA/JPL/USGS/California Geological Survey/Google

"UAVSAR's unprecedented resolution is allowing scientists to see fine details of the Baja earthquake's fault system activated by the main quake and its aftershocks," said UAVSAR Principal Investigator Scott Hensley of JPL. "Such details aren't visible with other sensors."

UAVSAR is part of NASA's ongoing effort to apply space-based technologies, ground-based techniques and complex computer models to advance our understanding of quakes and quake processes. The radar flew over Hispaniola earlier this year to study geologic processes following January's devastating Haiti quake. The data are giving scientists a baseline set of imagery in the event of future quakes. These images can then be combined with post-quake imagery to measure ground deformation, determine how slip on faults is distributed, and learn more about fault zone properties.

UAVSAR is also serving as a flying test bed to evaluate the tools and technologies for future space-based radars, such as those planned for a NASA mission currently in formulation called the Deformation, Ecosystem Structure and Dynamics of Ice, or DESDynI. That mission will study hazards such as earthquakes, volcanoes and landslides, as well as global environmental change.

For more information on UAVSAR, visit: http://uavsar.jpl.nasa.gov/ . JPL is managed for NASA by the California Institute of Technology in Pasadena.

For more information visit http://www.nasa.gov/topics/earth/features/UAVSAR20100623.html

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Earth-like Planets May Be Ready for Their Close-Up

Many scientists speculate that our galaxy could be full of places like Pandora from the movie "Avatar" -- Earth-like worlds in solar systems besides our own.

That doesn't mean such worlds have been easy to find, however. Of the 400-plus planets so far discovered, none could support life as we know it on Earth.

"The problem with finding Earth-like planets," said Stefan Martin, an engineer at NASA's Jet Propulsion Laboratory, Pasadena, Calif., "is that their host stars can emit 10 million times more infrared light than the planet itself. And because planets like ours are small and orbit very close to their respective stars, it makes Earths almost impossible to see."

Together with A.J. Booth (formerly at JPL and now at Sigma Space Corp., Lanham, Md.), Martin may have developed a way to make this almost impossible feat a reality.

Their instrument design, called a "nulling interferometer," observes planets in infrared light, where they are easier to detect. It is designed to combine starlight captured by four different telescopes, arranging the light waves from the star in such a way that they cancel each other out. "We're able to make the star look dimmer -- basically turning it off," Martin said.

Nulling interferometry is not a new idea, but what sets the results from Martin and Booth apart is how effective it turned out to be. "Our null depth is 10 to 100 times better than previously achieved by other systems," Martin said. "This is the first time someone has cross-combined four telescopes, set up in pairs, and achieved such deep nulls. It's extreme starlight suppression."

From left to right: JPLers Felipe Santos Fregoso, Piotr Szwaykowski, Kurt Liewer and Stefan Martin with the nulling interferometer testbed at JPL, where the device is built and refined. Image credit: NASA/JPL-Caltech

That suppression could allow scientists to get a better look at exoplanets than ever before. "We're able to make the planet flash on and off so that we can detect it," Martin said. "And because this system makes the light from the star appear 100 million times fainter, we would be able to see the planet we're looking for quite clearly."

Pandora, up close and personal

Nulling interferometry isn't the only way scientists can find other Earths. NASA's Kepler mission, currently in orbit, is looking for Earth-like planets by watching the light of faraway stars dim slightly as their planets pass in front of them. Another method of observing exoplanets is coronagraphy, which uses a mask to block the optical light of a star, making its surrounding planets more easily visible. And the proposed SIM Lite mission would also be able to find nearby planets by observing the gravity-induced "wobbling" of their host stars.

However, Martin and Booth's nulling interferometer could eventually give astronomers the ability to get up close and personal with Earth-like worlds, analyzing their atmospheres for signs of habitability or even possibly life. "We expect to eventually be able to see hundreds of planets with this technique," Martin said.

The technology that they've developed could be used on a follow-up space mission to SIM Lite and Kepler. Martin is now planning to test the system in conditions that better mimic a real-life mission.

Once considered the stuff of science fiction, it may not be long before Earth-like planets, or, in the case of Pandora, Earth-like moons of giant planets, are found to exist other places besides the silver screen.

For more information visit http://www.nasa.gov/topics/universe/features/pq20100623.html

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NASA Awards Launch Services Contract for OCO-2 Mission

PASADENA, Calif. – NASA has selected Orbital Sciences Corp. of Dulles, Va., to launch the Orbiting Carbon Observatory-2 (OCO-2) mission. The spacecraft will fly in February 2013 aboard a Taurus XL 3110 rocket launched from Vandenberg Air Force Base in California.

The total cost of the OCO-2 launch services is approximately $70 million. The estimated cost includes the task ordered launch service for a Taurus XL 3110 rocket, plus additional services under other contracts for payload processing, OCO-2 mission-unique support, launch vehicle integration, and tracking, data and telemetry support.

This is an artist’s concept of the Orbiting Carbon Observatory. Image credit: NASA/JPL

OCO-2 is NASA's first mission dedicated to studying atmospheric carbon dioxide. Carbon dioxide is the leading human-produced greenhouse gas driving changes in Earth's climate. OCO-2 will provide the first complete picture of human and natural carbon dioxide sources and "sinks," the places where the gas is pulled out of the atmosphere and stored. It will map the global geographic distribution of these sources and sinks and study their changes over time. The OCO-2 spacecraft will replace OCO-1, lost during a launch vehicle failure in 2009.

The OCO-2 project is managed by the Jet Propulsion Laboratory in Pasadena, Calif. NASA's Launch Services Program at the Kennedy Space Center in Florida is responsible for launch vehicle program management of the Taurus XL 3110 rocket.

For more information about NASA and agency missions, visit: http://www.nasa.gov . For more on OCO-2, visit: http://oco.jpl.nasa.gov/ .

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

For more information visit http://www.nasa.gov/mission_pages/oco/news/oco20100622.html

Jumbo Jellyfish or Massive Star?

Some might see a blood-red jellyfish in a forest of seaweed, while others might see a big, red eye or a pair of lips. In fact, the red-colored object in this new infrared image from NASA's Wide-field Infrared Survey Explorer (WISE) is a sphere of stellar innards, blown out from a humongous star.

The star (white dot in center of red ring) is one of the most massive stellar residents of our Milky Way galaxy. Objects like this are called Wolf-Rayet stars, after the astronomers who found the first few, and they make our sun look puny by comparison. Called V385 Carinae, this star is 35 times as massive as our sun, with a diameter nearly 18 times as large. It's hotter, too, and shines with more than one million times the amount of light.

Fiery candles like this burn out quickly, leading short lives of only a few million years. As they age, they blow out more and more of the heavier atoms cooking inside them -- atoms such as oxygen that are needed for life as we know it.

A cloud of material shed by a massive star can be seen in red in this new image from WISE. Image credit: NASA/JPL-Caltech/UCLA

The material is puffed out into clouds like the one that glows brightly in this WISE image. In this case, the hollow sphere showed up prominently only at the longest of four infrared wavelengths detected by WISE. Astronomers speculate this infrared light comes from oxygen atoms, which have been stripped of some of their electrons by ultraviolet radiation from the star. When the electrons join up again with the oxygen atoms, light is produced that WISE can detect with its 22-micron infrared light detector. The process is similar to what happens in fluorescent light bulbs.

Infrared light detected by WISE at 12 microns is colored green, while 3.4- and 4.6-micron light is blue. The green, kelp-looking material is warm dust, and the blue dots are stars in our Milky Way galaxy.

This image mosaic is made up of about 300 overlapping frames, taken as WISE continues its survey of the entire sky - an expansive search, sure to turn up more fascinating creatures swimming in our cosmic ocean.

V385 Carinae is located in the Carina constellation, about 16,000 light-years from Earth.

JPL manages 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.

For more information visit http://www.nasa.gov/mission_pages/WISE/news/wise20100617.html

JPL's Next Mars Rover Landing Radar Tested at Dryden

NASA's Dryden Flight Research Center recently provided logistics and range support for a NASA Jet Propulsion Laboratory team that tested a landing radar system for the next Mars rover mission adjacent to Dryden's Edwards Air Force Base facilities.

Brian Lataille of Wolfe Air Aviation and Charles Fisher of JPL prepare the engineering model of the Mars Science Laboratory descent radar on the nose gimbal of a helicopter during flight tests at NASA's Dryden Flight Research Center. The yellow disks are the radar's antennae. (NASA / Tony Landis)

Testing for the JPL-managed Mars Science Laboratory or MSL project included suspending a full-scale engineering model of the MSL rover from a helicopter and flying pre-planned flight trajectories over Rogers Dry Lake at Edwards to simulate the rover's descent stage carrying the rover to the surface of Mars. JPL engineers needed to verify that the radar will provide accurate altitude and velocity measurements at Mars and that the suspended rover will not confuse the ability of the descent stage's radar to accurately calculate the rover's descent speed for a safe, on-target landing.

"Dryden offers a unique location to perform testing of this kind," said Carrie Rhoades, the Dryden flight operations engineer managing the MSL project at Dryden. "We have restricted airspace and a large dry lakebed that is useful in simulating several Mars-like features. Dryden is also conveniently close to JPL, so troubleshooting the system and fixing any issues has been relatively easy to accomplish," she said.

The helicopter, carrying the MSL radar on a special nose-mounted gimbal system, mimicked the MSL's descent stage on which the radar will be mounted during the mission to Mars. The unique, rocket-powered descent stage will lower the rover, named Curiosity, on cables directly to the planet's surface in a maneuver dubbed “skycrane.” The descent stage will then fly away to a preplanned crash after releasing the cables, leaving Curiosity with its wheels on the Martian surface, ready to begin its search for ancient habitats.

In this computer-generated image, NASA's Mars Science Laboratory descent stage lowers the rover Curiosity to the Martian surface using the skycrane maneuver. (NASA / JPL-Caltech)

“Our JPL team is thrilled to have accomplished this critical radar field test at Dryden,” said Steven Lee, MSL’s Guidance, Navigation, and Control Systems manager. “The large, flat expanse of Rogers Dry Lake provided an ideal venue for our initial tests. The Dryden team did a great job accommodating our logistical and flight support needs, from hangar space to flight clearances.

"Preliminary results indicate the radar performs as expected and we look forward to continuing our field tests at other Mars-like sites including Amboy Crater, Cadiz Sand Dunes, and Death Valley," Lee added.

The new skycrane landing method was chosen for the next Mars mission because Curiosity will be the largest rover yet sent to Mars. It's too large for the airbag-cushioned landing method used by NASA's Mars Pathfinder mission in 1997 and the twin Mars Exploration Rover landings in 2004. Also, the MSL mission has a requirement for landing at a more-precise point on Mars than previous rover missions, aiding in the selection of the landing concept.

The Mars Science Laboratory descent stage radar attached to this Wolfe Air Aviation helicopter's nose gimbal was the focus of recent testing at NASA's Dryden Flight Research Center. (NASA / Tony Landis)

Starting in 2008, Dryden has flown an F/A-18 in a series of MSL developmental flights designed to collect environmental control system data to help validate the MSL radar system. In one flight series, the F/A-18 carried a Quick Test Experimental Pod housing the radar's environmental control hardware to an altitude of 47,000 feet and made a series of dives to simulate a high-speed entry into the Martian atmosphere. More of these flights are scheduled in the coming months to assist JPL in further verifying the MSL radar performance.

Mars Science Lab mission components such as Curiosity, the descent stage, the cruise stage and the aeroshell are currently undergoing assembly and testing at JPL in Pasadena, Calif., in preparation for an autumn 2011 launch. Curiosity is scheduled to reach Mars in the summer of 2012.

Wolfe Air Aviation, of Pasadena, Calif., provided their Eurocopter AS350 AStar helicopter and crew for the tests. The helicopter's Gyron gimbaled mounting system, provided by Nettman Systems International, is normally used to carry aerial video camera equipment for the motion picture industry.

For more information visit http://www.nasa.gov/mission_pages/msl/msl_rover_tests.html

Next Stop, Titan: Looking at the Land o' Lakes

NASA's Cassini spacecraft will be eyeing the north polar region of Saturn's moon Titan this weekend, scanning the moon's land o' lakes.

At closest approach on early morning Saturday, June 5 UTC, which is Friday afternoon, June 4 Pacific time, Cassini will glide to within about 2,000 kilometers (1,300 miles) of the Titan surface.

Cassini will make infrared scans of the north polar region, which was in darkness for the first several years of Cassini's tour around the Saturn system. The lighting has improved as northern spring has started to dawn over the area.

Artist's concept of Cassini's June 4, 2010, flyby of Saturn's moon Titan. Image credit: NASA/JPL

The visual and infrared spectrometer will be prime during closest approach, but the imaging science subsystem cameras will also be taking pictures. Among the scientific bounties, Cassini team members are hoping to get another good look at Kraken Mare, the largest lake on Titan, which covers a greater area than the Caspian Sea on Earth.

Although this latest flyby is dubbed "T69," planning changes early in the orbital tour made this the 70th targeted flyby of Titan.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL 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 visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100603.html

What is Consuming Hydrogen and Acetylene on Titan?

PASADENA, Calif. - Two new papers based on data from NASA's Cassini spacecraft scrutinize the complex chemical activity on the surface of Saturn's moon Titan. While non-biological chemistry offers one possible explanation, some scientists believe these chemical signatures bolster the argument for a primitive, exotic form of life or precursor to life on Titan's surface. According to one theory put forth by astrobiologists, the signatures fulfill two important conditions necessary for a hypothesized "methane-based life."

One key finding comes from a paper online now in the journal Icarus that shows hydrogen molecules flowing down through Titan's atmosphere and disappearing at the surface. Another paper online now in the Journal of Geophysical Research maps hydrocarbons on the Titan surface and finds a lack of acetylene.

This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on Titan, said Chris McKay, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif., who proposed a set of conditions necessary for this kind of methane-based life on Titan in 2005. One interpretation of the acetylene data is that the hydrocarbon is being consumed as food. But McKay said the flow of hydrogen is even more critical because all of their proposed mechanisms involved the consumption of hydrogen.

"We suggested hydrogen consumption because it's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," McKay said. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."

This artist concept shows a mirror-smooth lake on the surface of the smoggy moon Titan. Image credit: NASA/JPL

To date, methane-based life forms are only hypothetical. Scientists have not yet detected this form of life anywhere, though there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Fahrenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan's surface and much too cold to support life as we know it.

The list of liquid candidates is very short: liquid methane and related molecules like ethane. While liquid water is widely regarded as necessary for life, there has been extensive speculation published in the scientific literature that this is not a strict requirement.

The new hydrogen findings are consistent with conditions that could produce an exotic, methane-based life form, but do not definitively prove its existence, said Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore, Md., who authored the paper on hydrogen.

Strobel, who studies the upper atmospheres of Saturn and Titan, analyzed data from Cassini's composite infrared spectrometer and ion and neutral mass spectrometer in his new paper. The paper describes densities of hydrogen in different parts of the atmosphere and the surface. Previous models had predicted that hydrogen molecules, a byproduct of ultraviolet sunlight breaking apart acetylene and methane molecules in the upper atmosphere, should be distributed fairly evenly throughout the atmospheric layers.

Strobel found a disparity in the hydrogen densities that lead to a flow down to the surface at a rate of about 10,000 trillion trillion hydrogen molecules per second. This is about the same rate at which the molecules escape out of the upper atmosphere.

"It's as if you have a hose and you're squirting hydrogen onto the ground, but it's disappearing," Strobel said. "I didn't expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should 'float' to the top of the atmosphere and escape."

Strobel said it is not likely that hydrogen is being stored in a cave or underground space on Titan. The Titan surface is also so cold that a chemical process that involved a catalyst would be needed to convert hydrogen molecules and acetylene back to methane, even though overall there would be a net release of energy. The energy barrier could be overcome if there were an unknown mineral acting as the catalyst on Titan's surface.

The hydrocarbon mapping research, led by Roger Clark, a Cassini team scientist based at the U.S. Geological Survey in Denver, examines data from Cassini's visual and infrared mapping spectrometer. Scientists had expected the sun's interactions with chemicals in the atmosphere to produce acetylene that falls down to coat the Titan surface. But Cassini detected no acetylene on the surface.

In addition Cassini's spectrometer detected an absence of water ice on the Titan surface, but loads of benzene and another material, which appears to be an organic compound that scientists have not yet been able to identify. The findings lead scientists to believe that the organic compounds are shellacking over the water ice that makes up Titan's bedrock with a film of hydrocarbons at least a few millimeters to centimeters thick, but possibly much deeper in some places. The ice remains covered up even as liquid methane and ethane flow all over Titan's surface and fill up lakes and seas much as liquid water does on Earth.

"Titan's atmospheric chemistry is cranking out organic compounds that rain down on the surface so fast that even as streams of liquid methane and ethane at the surface wash the organics off, the ice gets quickly covered again," Clark said. "All that implies Titan is a dynamic place where organic chemistry is happening now."

The absence of detectable acetylene on the Titan surface can very well have a non-biological explanation, said Mark Allen, principal investigator with the NASA Astrobiology Institute Titan team. Allen is based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Allen said one possibility is that sunlight or cosmic rays are transforming the acetylene in icy aerosols in the atmosphere into more complex molecules that would fall to the ground with no acetylene signature.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Allen said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results - for example, reactions involving mineral catalysts."

"These new results are surprising and exciting," said Linda Spilker, Cassini project scientist at JPL. "Cassini has many more flybys of Titan that might help us sort out just what is happening at the surface."

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, 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.

For more information visit http://www.nasa.gov/topics/solarsystem/features/titan20100603.html