Cassini Spacecraft Captures Images And Sounds Of Big Saturn Storm

Dwayne C. Brown

Headquarters, Washington                               

 

Jia-Rui Cook

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- Scientists analyzing data from NASA's Cassini spacecraft now have the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth.

On Dec. 5, 2010, Cassini first detected the storm that has been raging ever since. It appears at approximately 35 degrees north latitude on Saturn. Pictures from Cassini's imaging cameras show the storm wrapping around the entire planet covering approximately 1.5 billion square miles (4 billion square kilometers).

The storm is about 500 times larger than the biggest storm previously seen by Cassini during several months from 2009 to 2010. Scientists studied the sounds of the new storm's lightning strikes and analyzed images taken between December 2010 and February 2011. Data from Cassini's radio and plasma wave science instrument showed the lightning flash rate as much as 10 times more frequent than during other storms monitored since Cassini's arrival to Saturn in 2004. The data appear in a paper published this week in the journal Nature.

"Cassini shows us that Saturn is bipolar," said Andrew Ingersoll, an author of the study and a Cassini imaging team member at the California Institute of Technology in Pasadena, Calif. "Saturn is not like Earth and Jupiter, where storms are fairly frequent. Weather on Saturn appears to hum along placidly for years and then erupt violently. I'm excited we saw weather so spectacular on our watch."

At its most intense, the storm generated more than 10 lightning flashes per second. Even with millisecond resolution, the spacecraft's radio and plasma wave instrument had difficulty separating individual signals during the most intense period. Scientists created a sound file from data obtained on March 15 at a slightly lower intensity period.

Cassini has detected 10 lightning storms on Saturn since the spacecraft entered the planet’s orbit and its southern hemisphere was experiencing summer, with full solar illumination not shadowed by the rings. Those storms rolled through an area in the southern hemisphere dubbed "Storm Alley." But the sun's illumination on the hemispheres flipped around August 2009, when the northern hemisphere began experiencing spring.

"This storm is thrilling because it shows how shifting seasons and solar illumination can dramatically stir up the weather on Saturn," said Georg Fischer, the paper's lead author and a radio and plasma wave science team member at the Austrian Academy of Sciences in Graz. "We have been observing storms on Saturn for almost seven years, so tracking a storm so different from the others has put us at the edge of our seats."

The storm's results are the first activities of a new "Saturn Storm Watch" campaign. During this effort, Cassini looks at likely storm locations on Saturn in between its scheduled observations. On the same day that the radio and plasma wave instrument detected the first lightning, Cassini's cameras happened to be pointed at the right location as part of the campaign and captured an image of a small bright cloud.

Because analysis on that image was not completed immediately, Fischer sent out a notice to the worldwide amateur astronomy community to collect more images. A flood of amateur images helped scientists track the storm as it grew rapidly, wrapping around the planet by late January 2011.

The new details about this storm complement atmospheric disturbances described recently by scientists using Cassini's composite infrared spectrometer and the European Southern Observatory's Very Large Telescope. The storm is the biggest observed by spacecraft orbiting or flying by Saturn. NASA's Hubble Space Telescope captured images in 1990 of an equally large storm.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. The imaging team is based at the Space Science Institute in Boulder, Colo.

For images and an audio file of the storm, visit http://www.nasa.gov/cassini.

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NASA Flies Greenhouse Gas Mission Over Nevada Salt Flat

Ruth Marlaire

Ames Research Center, Moffett Field, Calif.

MOFFETT FIELD, Calif. ­ Scientists from NASA's Ames Research Center, Moffett Field, Calif., joined a multi-institute team of researchers June 17-27, 2011, to investigate carbon dioxide and methane gas emissions from a dry lake bed and neighboring environment in Railroad Valley, Nev.

The Railroad Valley Vicarious Calibration Campaign, a collaboration between the Japan Aerospace Exploration Agency (JAXA), and NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., is an international, multi-year effort to calibrate space-based observations of carbon dioxide and methane collected by the Japanese Greenhouse Gases Observing Satellite (GOSAT), using ground and airborne data. The campaign is based at Railroad Valley, on a dry lake bed, or playa, about 75 miles southwest of Ely, Nev. It involves more than 30 scientists and engineers from JAXA, the University of Wisconsin, Madison, Colorado State University, Fort Collins and JPL. The Ames team supported the effort by providing ground and airborne measurements of carbon dioxide and methane. In addition, for the first time this year, the Ames team also investigated local sources of halophiles­ organisms that live in evaporated ponds where there are extreme concentrations of salts.

"We are pleased to offer these observations to our Japanese and Jet Propulsion Laboratory colleagues in support of the important task of very precisely measuring greenhouse gases from space. We look forward to continuing to support the GOSAT team and the upcoming NASA Orbiting Carbon Observatory -2 (OCO-2) mission," said Laura Iraci, an Earth science researcher from the Atmospheric Science Branch at Ames who planned and implemented the Ames effort.

During the campaign, the Ames team conducted a series of flights with an unmanned aircraft system (UAS), a modified Alpha Jet and a NASA ER-2 Earth resources aircraft, outfitted with AVIRIS, MASTER, and S-HIS instruments. NASA's ER-2 high-altitude aircraft flew over Railroad Valley carrying MASTER, AVIRIS and a digital camera system at an altitude of 65,000 feet complementing data collected by the other two aircraft at lower altitudes.

The UAS, known as the Sensor Integrated Environmental Remote Research Aircraft (SIERRA), carried sensors to measure greenhouse gases and winds and flew at altitudes of 100-2,500 feet above ground. The SIERRA flew two measurement missions: one to determine vertical profiles of carbon dioxide over the base camp on the playa, and measurements across the playa at low altitudes, and the second to map sources of natural and biogenic methane. SIERRA, which is operated out of Ames, flew from a public airstrip at Currant Ranch, Nev.

The second aircraft, an Alpha Jet, owned and operated by H211, LLC, flew to the Railroad Valley site from Ames and made a downward spiral around the base camp site. The spiral had a top altitude of approximately 25,000 feet, a bottom altitude near 5,000 feet, and an approximate three mile radius. The vertical profile took approximately 20 minutes to complete.

Ground observations showed what appeared to be bursts of carbon dioxide and methane from the soil of the salty lakebed. Preliminary tests suggest a possible surface, or subsurface, source for these gas emissions. These findings are important to both Earth and planetary scientists: greenhouse gases contribute to global warming, and recent scientific findings of Mars¹ surface suggest evidence that there were large bodies of salt water in the past. Both perspectives emphasize a need to further investigate these types of environments for past and present life. For example, methane has been reported in the atmosphere of Mars, and is known to be produced by microbial mats that are present in the most salty environments on Earth.

To study the source of gas emissions, Chris McKay and Brad Bebout, space science researchers from Ames, led a team to observe biogenic and non-biogenic sources of methane in the Railroad Valley area. Using data loggers inserted near the surface and at depths of 20 and 30 cm to monitor the temperature and moisture of the soil, the space team collected soil and gas samples for further study in the laboratory. In addition, the SIERRA flew over potential methane sources on June 18 and 21, while the ground-based team collected concurrently carbon dioxide observations on the ground June 21.

"Although there is a general understanding of the natural and anthropogenic sources and sinks of carbon dioxide and methane, their fluctuations must be better quantified to better forecast and mitigate global climate change. These measurements over the dry, salt flat will help us better measure the spatial distribution and heterogeneity of greenhouse gases," said Bebout.

This work also is important to NASA's goals in Astrobiology. Methane has been reported on Mars and pinpointing sources and determining whether or not the methane is biogenic will also be important there. According to Bebout: "We can use Railroad Valley and other Mars analogue sites to help interpret methane data to be returned from upcoming Mars missions, including Mars Science Laboratory and the 2016 ExoMars Trace Gas Orbiter."

For more information about Ames, visit http://www.nasa.gov/ames.

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Cassini Spacecraft Captures Images And Sounds Of Big Saturn Storm

Dwayne C. Brown

Headquarters, Washington                               

 

Jia-Rui Cook

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- Scientists analyzing data from NASA's Cassini spacecraft now have the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth.

On Dec. 5, 2010, Cassini first detected the storm that has been raging ever since. It appears at approximately 35 degrees north latitude on Saturn. Pictures from Cassini's imaging cameras show the storm wrapping around the entire planet covering approximately 1.5 billion square miles (4 billion square kilometers).

The storm is about 500 times larger than the biggest storm previously seen by Cassini during several months from 2009 to 2010. Scientists studied the sounds of the new storm's lightning strikes and analyzed images taken between December 2010 and February 2011. Data from Cassini's radio and plasma wave science instrument showed the lightning flash rate as much as 10 times more frequent than during other storms monitored since Cassini's arrival to Saturn in 2004. The data appear in a paper published this week in the journal Nature.

"Cassini shows us that Saturn is bipolar," said Andrew Ingersoll, an author of the study and a Cassini imaging team member at the California Institute of Technology in Pasadena, Calif. "Saturn is not like Earth and Jupiter, where storms are fairly frequent. Weather on Saturn appears to hum along placidly for years and then erupt violently. I'm excited we saw weather so spectacular on our watch."

At its most intense, the storm generated more than 10 lightning flashes per second. Even with millisecond resolution, the spacecraft's radio and plasma wave instrument had difficulty separating individual signals during the most intense period. Scientists created a sound file from data obtained on March 15 at a slightly lower intensity period.

Cassini has detected 10 lightning storms on Saturn since the spacecraft entered the planet’s orbit and its southern hemisphere was experiencing summer, with full solar illumination not shadowed by the rings. Those storms rolled through an area in the southern hemisphere dubbed "Storm Alley." But the sun's illumination on the hemispheres flipped around August 2009, when the northern hemisphere began experiencing spring.

"This storm is thrilling because it shows how shifting seasons and solar illumination can dramatically stir up the weather on Saturn," said Georg Fischer, the paper's lead author and a radio and plasma wave science team member at the Austrian Academy of Sciences in Graz. "We have been observing storms on Saturn for almost seven years, so tracking a storm so different from the others has put us at the edge of our seats."

The storm's results are the first activities of a new "Saturn Storm Watch" campaign. During this effort, Cassini looks at likely storm locations on Saturn in between its scheduled observations. On the same day that the radio and plasma wave instrument detected the first lightning, Cassini's cameras happened to be pointed at the right location as part of the campaign and captured an image of a small bright cloud.

Because analysis on that image was not completed immediately, Fischer sent out a notice to the worldwide amateur astronomy community to collect more images. A flood of amateur images helped scientists track the storm as it grew rapidly, wrapping around the planet by late January 2011.

The new details about this storm complement atmospheric disturbances described recently by scientists using Cassini's composite infrared spectrometer and the European Southern Observatory's Very Large Telescope. The storm is the biggest observed by spacecraft orbiting or flying by Saturn. NASA's Hubble Space Telescope captured images in 1990 of an equally large storm.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. The imaging team is based at the Space Science Institute in Boulder, Colo.

For images and an audio file of the storm, visit http://www.nasa.gov/cassini.

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Rhea's Return

Rhea emerges ... After being occulted by the larger moon Titan.

Occultation is a celestial event in which a larger body covers up a distant object. Observations such as this one, in which one moon passes close to or in front of another, help scientists refine their understanding of the orbits of Saturn's moons. Titan is about 621,000 miles (1 million kilometers) from Cassini in this image. Rhea is about 1.4 million miles (2.3 million kilometers) from Cassini.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Oct. 27, 2009. Image scale is 4 miles (6 kilometers) per pixel on Titan and 9 miles (14 kilometers) per pixel on Rhea.

Image Credit: NASA/JPL/Space Science Institute

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NASA'S Spitzer Finds Distant Galaxies Grazed On Gas

Trent J. Perrotto

Headquarters, Washington

 

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

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

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

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

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

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

Galaxies like our Milky Way are giant collections of stars, gas and dust. They grow in size by feeding off gas and converting it to new stars. A long-standing question in astronomy is: Where did distant galaxies that formed billions of years ago acquire this stellar fuel?

The most favored theory was that galaxies grew by merging with other galaxies, feeding off gas stirred up in the collisions.

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

Previous studies using ultraviolet-light telescopes found about six times less star formation than Spitzer, which sees infrared light.

Scientists think this may be due to large amounts of obscuring dust, through which infrared light can sneak. Spitzer opened a new window onto the galaxies by taking very long-exposure infrared images of a patch of sky called the GOODS fields, for Great Observatories Origins Deep Survey.

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

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La Niña's Exit Leaves Climate Forecasts in Limbo

It's what Bill Patzert, a climatologist and oceanographer at NASA's Jet Propulsion Laboratory in Pasadena, Calif., likes to call a "La Nada" – that puzzling period between cycles of the El Niño-Southern Oscillation climate pattern in the Pacific Ocean when sea surface heights in the equatorial Pacific are near average.

The comings and goings of El Niño and La Niña are part of a long-term, evolving state of global climate, for which measurements of sea surface height are a key indicator. For the past three months, since last year's strong La Niña event dissipated, data collected by the U.S.-French Ocean Surface Topography Mission (OSTM)/Jason-2 oceanography satellite have shown that the equatorial Pacific sea surface heights have been stable and near average. Elsewhere, however, the northeastern Pacific Ocean remains quite cool, with sea levels much lower than normal. The presence of cool ocean waters off the U.S. West Coast has also been a factor in this year's cool and foggy spring there.

The current state of the Pacific is shown in this OSTM/Jason-2 image, based on the average of 10 days of data centered on June 18, 2011. The image depicts places where Pacific sea surface height is higher (warmer) than normal as yellow and red, while places where the sea surface is lower (cooler) than normal are shown in blue and purple. Green indicates near-normal conditions. Sea surface height is an indicator of how much of the sun's heat is stored in the upper ocean.

For oceanographers and climate scientists like Patzert, "La Nada" conditions can bring with them a high degree of uncertainty. While some forecasters (targeting the next couple of seasons) have suggested La Nada will bring about "normal" weather conditions, Patzert cautions previous protracted La Nadas have often delivered unruly jet stream patterns and wild weather swings.

In addition, some climatologists are pondering whether a warm El Niño pattern (which often follows La Niña) may be lurking over the horizon. Patzert says that would be perfectly fine for the United States.

"For the United States, there would be some positives to the appearance of El Niño this summer," Patzert said. "The parched and fire-ravaged southern tier of the country would certainly benefit from a good El Niño soaking. Looking ahead to late August and September, El Niño would also tend to dampen the 2011 hurricane season in the United States. We've had enough wild and punishing weather this year. Relief from the drought across the southern United States and a mild hurricane season would be very welcome."

Jason-2 scientists will continue to monitor Pacific Ocean sea surface heights for signs of El Niño, La Niña or prolonged neutral conditions.

JPL manages the U.S. portion of the OSTM/Jason-2 mission for NASA's Science Mission Directorate, Washington, D.C.

For more information on NASA's ocean surface topography missions, visit: http://sealevel.jpl.nasa.gov/missions/.

To view the latest Jason-1 and OSTM/Jason-2 data, visit http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/.

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

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NASA Will Host 150 People For Tweetup At Launch Of Jupiter-Bound Mission

Stephanie L. Schierholz

Headquarters, Washington                               

 

Veronica McGregor

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- NASA will host a two-day launch Tweetup for 150 of its Twitter followers on Aug. 4 - 5 at the agency's Kennedy Space Center in Florida. The Tweetup is expected to culminate in the launch of the Jupiter-bound Juno spacecraft aboard an Atlas V rocket.

The launch window opens at 11:39 a.m. EDT on Aug. 5. The spacecraft is expected to arrive at Jupiter in 2016. The mission will investigate the gas giant's origins, structure, atmosphere and magnetosphere. Juno's color camera will provide close-up images of Jupiter, including the first detailed glimpse of the planet's poles.

The Tweetup will provide @NASA Twitter followers with the opportunity to tour the Kennedy Space Center Visitor Complex; speak with scientists and engineers from the Juno and other upcoming missions; and, if all goes as scheduled, view the spacecraft launch. The event also will provide participants the opportunity to meet fellow tweeps and members of NASA's social media team.

Juno is the second of four space missions launching this year, making 2011 one of the busiest ever in planetary exploration. Aquarius was launched June 10 to study ocean salinity; Grail will launch Sept. 8 to study the moon's gravity field; and the Mars Science Laboratory/Curiosity rover heads to the Red Planet no earlier than Nov. 25.

Tweetup registration opens at 3 p.m. on Friday, June 24, and closes at 3 p.m. on Monday, June 27. NASA will randomly select 150 participants from online registrations. For more information about the Tweetup and registration, visit http://www.nasa.gov/tweetup.

For information about connecting and collaborating with NASA, visit http://www.nasa.gov/connect.

Juno's principal investigator is Scott Bolton of the Southwest Research Institute in San Antonio. NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the mission.

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

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NASA Mars Rover Arrives In Florida After Cross-Country Flight

Dwayne Brown     

Headquarters, Washington

 

George Diller

Kennedy Space Center, Fla.

 

Guy Webster

Jet Propulsion Laboratory, Pasadena, Calif.

KENNEDY SPACE CENTER, Fla. -- NASA's next Mars rover has completed the journey from its California birthplace to Florida in preparation for launch this fall.

The Mars Science Laboratory (MSL) rover, also known as Curiosity, arrived Wednesday at NASA's Kennedy Space Center aboard an Air Force C-17 transport plane. It was accompanied by the rocket-powered descent stage that will fly the rover during the final moments before landing on Mars. The C-17 flight began at March Air Reserve Base in Riverside, Calif., where the boxed hardware had been trucked from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

The rover's aeroshell -- the protective covering for the trip to the Red Planet -- and the cruise stage, which will guide it to Mars, arrived at Kennedy last month. The mission is targeted to launch from Cape Canaveral Air Force Station between Nov. 25 and Dec. 18. The car-size rover will land on Mars in August 2012.

"The design and building part of the mission is nearly behind us now," said JPL's David Gruel, who has managed Mars Science Laboratory assembly, test and launch operations since 2007. "We're getting to final checkouts before sending the rover on its way to Mars."

The rover and other spacecraft components will undergo more testing before mission staff stack them and fuel the onboard propulsion systems. Curiosity should be enclosed in its aeroshell for the final time in September and delivered to Kennedy's Launch Complex 41 in early November for integration with a United Launch Alliance Atlas V rocket.

Curiosity is about twice as long and more than five times as heavy as any previous Mars rover. Its 10 science instruments include two for ingesting and analyzing samples of powdered rock delivered by the rover's robotic arm. During a prime mission lasting one Martian year -- nearly two Earth years -- researchers will use the rover's tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed.

JPL built the rover and descent stage and manages the mission for NASA's Science Mission Directorate in Washington. Launch management for the mission is the responsibility of NASA's Launch Services Program at Kennedy.

For more information about the mission, visit http://www.nasa.gov/msl.

To follow the mission on Facebook and Twitter, visit http://www.facebook.com/marscuriosity or http://www.twitter.com/marscuriosity.

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First TV Image of Mars

A 'real-time data translator' machine converted a Mariner 4 digital image data into numbers printed on strips of paper. Too anxious to wait for the official processed image, employees from the Voyager Telecommunications Section at NASA's Jet Propulsion Laboratory, attached these strips side by side to a display panel and hand colored the numbers like a paint-by-numbers picture. The completed image was framed and presented to JPL director, William H. Pickering. Mariner 4 was launched on November 28, 1964 and journeyed for 228 days to the Red Planet, providing the first close-range images of Mars.

The spacecraft carried a television camera and six other science instruments to study the Martian atmosphere and surface. The 22 photographs taken by Mariner revealed the existence of lunar type craters upon a desert-like surface. After completing its mission, Mariner 4 continued past Mars to the far side of the Sun. On Dec. 20, 1967, all operations of the spacecraft were ended.

Visit http://photojournal.jpl.nasa.gov/catalog/PIA14033 for more information.

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NASA Probe Nears Position for Year-Long Stay at Giant Asteroid

Dwayne C. Brown

Headquarters, Washington                               

 

Priscilla Vega/Jia-Rui Cook

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- NASA's Dawn spacecraft is on track to begin the first extended visit to a large asteroid. The mission expects to go into orbit around Vesta on July 16 and begin gathering science data in early August. Vesta resides in the main asteroid belt and is thought to be the source of a large number of meteorites that fall to Earth.

"The spacecraft is right on target," said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We look forward to exploring this unknown world during Dawn's one year stay in Vesta's orbit."

After traveling nearly four years and 1.7 billion miles (2.7 billion kilometers), Dawn is approximately 96,000 miles (155,000 kilometers) away from Vesta. When Vesta captures Dawn into its orbit, there will be approximately 9,900 miles (16,000 kilometers) between them. They will be approximately 117 million miles (188 million kilometers) away from Earth.

After Dawn enters Vesta's orbit, engineers will need a few days to determine the exact time of capture. Unlike other missions where a dramatic, nail-biting propulsive burn results in orbit insertion around a planet, Dawn has been using its placid ion propulsion system to subtly shape its path for years to match Vesta's orbit around the sun.

Images from Dawn's framing camera, taken for navigation purposes, show the slow progress toward Vesta. They also show Vesta rotating about 65 degrees in the field of view. The images are about twice as sharp as the best images of Vesta from NASA's Hubble Space Telescope, but the surface details Dawn will obtain are still a mystery.

"Navigation images from Dawn's framing camera have given us intriguing hints of Vesta, but we're looking forward to the heart of Vesta operations, when we begin officially collecting science data," said Christopher Russell, Dawn principal investigator, at the University of California, Los Angeles (UCLA). "We can't wait for Dawn to peel back the layers of time and reveal the early history of our solar system."

Dawn's three instruments are all functioning and appear to be properly calibrated. The visible and infrared mapping spectrometer, for example, has started to obtain images of Vesta that are larger than a few pixels in size. During the initial reconnaissance orbit, at approximately 1,700 miles (2,700 kilometers), the spacecraft will get a broad overview of Vesta with color pictures and data in different wavelengths of reflected light. The spacecraft will move into a high altitude mapping orbit, about 420 miles (680 kilometers) above the surface to systematically map the parts of Vesta's surface illuminated by the sun; collect stereo images to see topographic highs and lows; acquire higher resolution data to map rock types at the surface; and learn more about Vesta's thermal properties.

Dawn then will move even closer, to a low-altitude mapping orbit approximately 120 miles (200 kilometers) above the surface. The primary science goals of this orbit are to detect the byproducts of cosmic rays hitting the surface and help scientists determine the many kinds of atoms there, and probe the protoplanet's internal structure. As Dawn spirals away from Vesta, it will pause again at the high-altitude mapping orbit altitude. Because the sun's angle on the surface will have progressed, scientists will be able to see previously hidden terrain while obtaining different views of surface features.

"We've packed our year at Vesta chock-full of science observations to help us unravel the mysteries of Vesta," said Carol Raymond, Dawn's deputy principal investigator at JPL. Vesta is considered a protoplanet, or body that never quite became a full-fledged planet.

Dawn launched in September 2007. Following a year at Vesta, the spacecraft will depart for its second destination, the dwarf planet Ceres, in July 2012. Dawn's mission to Vesta and Ceres is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala.

UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. of Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are part of the mission team.

For more information about Dawn, visit http://www.nasa.gov/dawn.

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NASA Probe Nears Position for Year-Long Stay at Giant Asteroid

Dwayne C. Brown

Headquarters, Washington                                

 

Priscilla Vega/Jia-Rui Cook

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- NASA's Dawn spacecraft is on track to begin the first extended visit to a large asteroid. The mission expects to go into orbit around Vesta on July 16 and begin gathering science data in early August. Vesta resides in the main asteroid belt and is thought to be the source of a large number of meteorites that fall to Earth.

"The spacecraft is right on target," said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We look forward to exploring this unknown world during Dawn's one year stay in Vesta's orbit."

After traveling nearly four years and 1.7 billion miles (2.7 billion kilometers), Dawn is approximately 96,000 miles (155,000 kilometers) away from Vesta. When Vesta captures Dawn into its orbit, there will be approximately 9,900 miles (16,000 kilometers) between them. They will be approximately 117 million miles (188 million kilometers) away from Earth.

After Dawn enters Vesta's orbit, engineers will need a few days to determine the exact time of capture. Unlike other missions where a dramatic, nail-biting propulsive burn results in orbit insertion around a planet, Dawn has been using its placid ion propulsion system to subtly shape its path for years to match Vesta's orbit around the sun.

Images from Dawn's framing camera, taken for navigation purposes, show the slow progress toward Vesta. They also show Vesta rotating about 65 degrees in the field of view. The images are about twice as sharp as the best images of Vesta from NASA's Hubble Space Telescope, but the surface details Dawn will obtain are still a mystery.

"Navigation images from Dawn's framing camera have given us intriguing hints of Vesta, but we're looking forward to the heart of Vesta operations, when we begin officially collecting science data," said Christopher Russell, Dawn principal investigator, at the University of California, Los Angeles (UCLA). "We can't wait for Dawn to peel back the layers of time and reveal the early history of our solar system."

Dawn's three instruments are all functioning and appear to be properly calibrated. The visible and infrared mapping spectrometer, for example, has started to obtain images of Vesta that are larger than a few pixels in size. During the initial reconnaissance orbit, at approximately 1,700 miles (2,700 kilometers), the spacecraft will get a broad overview of Vesta with color pictures and data in different wavelengths of reflected light. The spacecraft will move into a high altitude mapping orbit, about 420 miles (680 kilometers) above the surface to systematically map the parts of Vesta's surface illuminated by the sun; collect stereo images to see topographic highs and lows; acquire higher resolution data to map rock types at the surface; and learn more about Vesta's thermal properties.

Dawn then will move even closer, to a low-altitude mapping orbit approximately 120 miles (200 kilometers) above the surface. The primary science goals of this orbit are to detect the byproducts of cosmic rays hitting the surface and help scientists determine the many kinds of atoms there, and probe the protoplanet's internal structure. As Dawn spirals away from Vesta, it will pause again at the high-altitude mapping orbit altitude. Because the sun's angle on the surface will have progressed, scientists will be able to see previously hidden terrain while obtaining different views of surface features.

"We've packed our year at Vesta chock-full of science observations to help us unravel the mysteries of Vesta," said Carol Raymond, Dawn's deputy principal investigator at JPL. Vesta is considered a protoplanet, or body that never quite became a full-fledged planet.

Dawn launched in September 2007. Following a year at Vesta, the spacecraft will depart for its second destination, the dwarf planet Ceres, in July 2012. Dawn's mission to Vesta and Ceres is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala.

UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. of Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are part of the mission team.

For more information about Dawn, visit http://www.nasa.gov/dawn

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NASA Mission Suggests Sun And Planets Constructed Differently

Dwayne Brown

Headquarters, Washington                                   

 

DC Agle

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- Analysis of samples returned by NASA’s Genesis mission indicates our sun and its inner planets may have formed differently than scientists previously thought.

The data revealed slight differences in the types of oxygen and nitrogen present on the sun and planets. The elements are among the most abundant in our solar system. Although the differences are slight, the implications could help determine how our solar system evolved.

The air on Earth contains three different kinds of oxygen atoms, which are differentiated by the number of neutrons they contain. Nearly 100 percent of oxygen atoms in the solar system are composed of O-16, but there also are tiny amounts of more exotic oxygen isotopes called O-17 and O-18. Researchers studying the oxygen of Genesis samples found that the percentage of O-16 in the sun is slightly higher than on Earth, the moon, and meteorites. The other isotopes’ percentages were slightly lower.

"The implication is that we did not form out of the same solar nebula materials that created the sun -- just how and why remains to be discovered," said Kevin McKeegan, a Genesis co-investigator from the University of California, Los Angeles and the lead author of one of two Science papers published this week.

The second paper detailed differences in the amount of nitrogen on the sun and planets. Like oxygen, nitrogen has one isotope, N-14, that makes up nearly 100 percent of the atoms in the solar system, but there also is a tiny amount of N-15. Researchers studying the same samples saw that when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition.

"These findings show that all solar system objects, including the terrestrial planets, meteorites and comets, are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co-investigator from Centre de Recherches Petrographiques et Geochimiques in Nancy, France and the lead author of the second new Science paper. "Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system."

Data were obtained from analysis of Genesis samples collected from the solar wind -- the material ejected from the outer portion of the sun. This material can be thought of as a fossil of our nebula because the preponderance of scientific evidence suggests that the outer layer of our sun has not changed measurably for billions of years.

"The sun houses more than 99 percent of the material currently in our solar system so it's a good idea to get to know it better," said Genesis principal investigator Don Burnett of the California Institute of Technology in Pasadena, Calif. "While it was more challenging than expected we have answered some important questions, and like all successful missions, generated plenty more."

Genesis launched in August 2000. The spacecraft traveled to Earth’s L1 Lagrange Point about 1 million miles from Earth, where it remained for 886 days between 2001 and 2004, passively collecting solar-wind samples.

On Sept. 8, 2004, the spacecraft released a sample return capsule, which made a hard landing as a result of a failed parachute in the Utah Test and Training Range in Dugway, Utah. This marked NASA’s first sample return since the final Apollo lunar mission in 1972, and the first material collected beyond the moon. NASA’s Johnson Space Center in Houston curates the samples and supports analysis and sample allocation.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed the Genesis mission for NASA’s Science Mission Directorate in Washington. The Genesis mission was part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver developed and operated the spacecraft. Analysis at the Centre de Recherches Petrographiques et Geochimiques was supported by the Centre National d’Etudes Spatiales and the French National Center for Scientific Research in Paris.

For more information on the Genesis mission, visit http://genesismission.jpl.nasa.gov.

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NASA Mars Rover Arrives In Florida After Cross-Country Flight

Dwayne Brown     

Headquarters, Washington

 

George Diller

Kennedy Space Center, Fla.

 

Guy Webster

Jet Propulsion Laboratory, Pasadena, Calif.

KENNEDY SPACE CENTER, Fla. -- NASA's next Mars rover has completed the journey from its California birthplace to Florida in preparation for launch this fall.

The Mars Science Laboratory (MSL) rover, also known as Curiosity, arrived Wednesday at NASA's Kennedy Space Center aboard an Air Force C-17 transport plane. It was accompanied by the rocket-powered descent stage that will fly the rover during the final moments before landing on Mars. The C-17 flight began at March Air Reserve Base in Riverside, Calif., where the boxed hardware had been trucked from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

The rover's aeroshell -- the protective covering for the trip to the Red Planet -- and the cruise stage, which will guide it to Mars, arrived at Kennedy last month. The mission is targeted to launch from Cape Canaveral Air Force Station between Nov. 25 and Dec. 18. The car-size rover will land on Mars in August 2012.

"The design and building part of the mission is nearly behind us now," said JPL's David Gruel, who has managed Mars Science Laboratory assembly, test and launch operations since 2007. "We're getting to final checkouts before sending the rover on its way to Mars."

The rover and other spacecraft components will undergo more testing before mission staff stack them and fuel the onboard propulsion systems. Curiosity should be enclosed in its aeroshell for the final time in September and delivered to Kennedy's Launch Complex 41 in early November for integration with a United Launch Alliance Atlas V rocket.

Curiosity is about twice as long and more than five times as heavy as any previous Mars rover. Its 10 science instruments include two for ingesting and analyzing samples of powdered rock delivered by the rover's robotic arm. During a prime mission lasting one Martian year -- nearly two Earth years -- researchers will use the rover's tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed.

JPL built the rover and descent stage and manages the mission for NASA's Science Mission Directorate in Washington. Launch management for the mission is the responsibility of NASA's Launch Services Program at Kennedy.

For more information about the mission, visit http://www.nasa.gov/msl.

To follow the mission on Facebook and Twitter, visit http://www.facebook.com/marscuriosity or http://www.twitter.com/marscuriosity.

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NASA Cassini Spacecraft Captures Ocean-Like Spray At Saturn Moon

Dwayne C. Brown

Headquarters, Washington                          

 

Jia-Rui Cook

Jet Propulsion Laboratory, Pasadena, Calif.

 

Markus Bauer

European Space Agency

 

WASHINGTON -- NASA's Cassini spacecraft has discovered the best evidence yet for a large-scale saltwater reservoir beneath the icy crust of Saturn's moon Enceladus. The data came from the spacecraft's direct analysis of salt-rich ice grains close to the jets ejected from the moon.

Data from Cassini's cosmic dust analyzer show the grains expelled from fissures, known as tiger stripes, are relatively small and usually low in salt far away from the moon. But closer to the moon's surface, Cassini found that relatively large grains rich with sodium and potassium dominate the plumes. The salt-rich particles have an "ocean-like" composition and indicate that most, if not all, of the expelled ice and water vapor comes from the evaporation of liquid salt-water. The findings appear in this week's issue of the journal Nature.

"There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus's icy surface," said Frank Postberg, a Cassini team scientist at the University of Heidelberg, Germany, and the lead author on the paper. When water freezes, the salt is squeezed out, leaving pure water ice behind. If the plumes emanated from ice, they should have very little salt in them.

The Cassini mission discovered Enceladus' water-vapor and ice jets in 2005. In 2009, scientists working with the cosmic dust analyzer examined some sodium salts found in ice grains of Saturn's E ring, the outermost ring that gets its material primarily from Enceladean jets. But the link to subsurface salt water was not definitive.

The new paper analyzes three Enceladus flybys in 2008 and 2009 with the same instrument, focusing on the composition of freshly ejected plume grains. The icy particles hit the detector target at speeds between 15,000 and 39,000 mph (23,000 and 63,000 kilometers per hour), vaporizing instantly. Electrical fields inside the cosmic dust analyzer separated the various constituents of the impact cloud.

The data suggest a layer of water between the moon's rocky core and its icy mantle, possibly as deep as about 50 miles (80 kilometers) beneath the surface. As this water washes against the rocks, it dissolves salt compounds and rises through fractures in the overlying ice to form reserves nearer the surface. If the outermost layer cracks open, the decrease in pressure from these reserves to space causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of water vapor is lost every second in the plumes, with smaller amounts being lost as ice grains. The team calculates the water reserves must have large evaporating surfaces, or they would freeze easily and stop the plumes.

"This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets," said Nicolas Altobelli, the European Space Agency's project scientist for Cassini.

Cassini's ultraviolet imaging spectrograph also recently obtained complementary results that support the presence of a subsurface ocean. A team of Cassini researchers led by Candice Hansen of the Planetary Science Institute in Tucson, Ariz., measured gas shooting out of distinct jets originating in the moon's south polar region at five to eight times the speed of sound, several times faster than previously measured. These observations of distinct jets, from a 2010 flyby, are consistent with results showing a difference in composition of ice grains close to the moon's surface and those that made it out to the E ring. The paper was published in the June 9 issue of Geophysical Research Letters.

"Without an orbiter like Cassini to fly close to Saturn and its moons -- to taste salt and feel the bombardment of ice grains -- scientists would never have known how interesting these outer solar system worlds are," said Linda Spilker, NASA's Cassini project scientist at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The mission is managed by JPL for NASA's Science Mission Directorate in Washington.

For more information about Cassini, visit http://www.nasa.gov/cassini.

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