Nov 16 2011

From The Space Library

RELEASE: 11-386 NASA PROBE DATA SHOW EVIDENCE OF LIQUID WATER ON ICY EUROPA

WASHINGTON -- Data from a NASA planetary mission have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupiter's moon, Europa. The data suggest there is significant exchange between Europa's icy shell and the ocean beneath. This information could bolster arguments that Europa's global subsurface ocean represents a potential habitat for life elsewhere in our solar system. The findings are published in the scientific journal Nature. "The data opens up some compelling possibilities," said Mary Voytek, director of NASA's Astrobiology Program at agency headquarters in Washington. "However, scientists worldwide will want to take a close look at this analysis and review the data before we can fully appreciate the implication of these results." NASA's Galileo spacecraft, launched by the space shuttle Atlantis in 1989 to Jupiter, produced numerous discoveries and provided scientists decades of data to analyze. Galileo studied Jupiter, which is the most massive planet in the solar system, and some of its many moons. One of the most significant discoveries was the inference of a global salt water ocean below the surface of Europa. This ocean is deep enough to cover the whole surface of Europa and contains more liquid water than all of Earth's oceans combined. However, being far from the sun, the ocean surface is completely frozen. Most scientists think this ice crust is tens of miles thick. "One opinion in the scientific community has been if the ice shell is thick, that's bad for biology. That might mean the surface isn't communicating with the underlying ocean," said Britney Schmidt, lead author of the paper and postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin. "Now, we see evidence that it's a thick ice shell that can mix vigorously and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable." Schmidt and her team focused on Galileo images of two roughly circular, bumpy features on Europa's surface called chaos terrains. Based on similar processes seen on Earth -- on ice shelves and under glaciers overlaying volcanoes -- they developed a four-step model to explain how the features form. The model resolves several conflicting observations. Some seemed to suggest the ice shell is thick. Others suggest it is thin. This recent analysis shows the chaos features on Europa's surface may be formed by mechanisms that involve significant exchange between the icy shell and the underlying lake. This provides a mechanism or model for transferring nutrients and energy between the surface and the vast global ocean already inferred to exist below the thick ice shell. This is thought to increase the potential for life there. The study authors have good reason to believe their model is correct, based on observations of Europa from Galileo and of Earth. Still, because the inferred lakes are several miles below the surface, the only true confirmation of their presence would come from a future spacecraft mission designed to probe the ice shell. Such a mission was rated as the second highest priority flagship mission by the National Research Council's recent Planetary Science Decadal Survey and is being studied by NASA. "This new understanding of processes on Europa would not have been possible without the foundation of the last 20 years of observations over Earth's ice sheets and floating ice shelves," said Don Blankenship, a co-author and senior research scientist at the Institute for Geophysics, where he leads airborne radar studies of the planet's ice sheets. Galileo was the first spacecraft to directly measure Jupiter's atmosphere with a probe and conduct long-term observations of the Jovian system. The probe was the first to fly by an asteroid and discover the moon of an asteroid. NASA extended the mission three times to take advantage of Galileo's unique science capabilities, and it was put on a collision course into Jupiter's atmosphere in September 2003 to eliminate any chance of impacting Europa. The Galileo mission was managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., for the agency's Science Mission Directorate.

RELEASE: 11-387 NASA INVITES 150 LUCKY TWITTER FOLLOWERS TO LAUNCH OF MARS ROVER

WASHINGTON -- NASA has invited 150 followers of the agency's Twitter account to a two-day launch Tweetup on Nov. 23 and 25 at the agency's Kennedy Space Center in Florida. The Tweetup is expected to culminate in the launch of the Mars Science Laboratory's Curiosity rover aboard an Atlas V rocket from nearby Cape Canaveral Air Force Station. The launch window is scheduled to open at 10:25 a.m. EST on Nov. 25. Curiosity's arrival at Mars is anticipated in August 2012 near Gale Crater. During the nearly two-year prime mission, the rover will investigate whether a selected area of Mars offered environmental conditions favorable for microbial life and preserved that evidence, if it existed. Tweetup participants were selected from more than 1,050 people who registered online. They will share their Tweetup experiences with their followers through the social networking site Twitter. Participants represent the United States, Australia, Belgium, Brazil, Canada, France, Germany, Ireland, Spain and the United Kingdom. Attendees from the U.S. come from the District of Columbia and 37 states: Alabama, Arizona, California, Connecticut, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Virginia, Washington and Wisconsin. Beginning at 11 a.m. on Wednesday, Nov. 23, NASA will broadcast a portion of the Tweetup when attendees talk with Jim Green, Planetary Science division director, and Doug McCuistion, Mars Exploration program director, both at NASA Headquarters in Washington. Engineers from NASA's Jet Propulsion Laboratory, Pasadena, Calif., where the rover was designed and built will speak, as will mission scientists. Participants also will tour Kennedy and Cape Canaveral, including a close-up visit to the launch pad. On launch day, they will speak with NASA Administrator Charles Bolden; Leland Melvin, NASA's assistant administrator for education; astronaut Doug Wheelock and Bill Nye the Science Guy. NASA has invited its Twitter followers to attend eight previous launches: NASA's newest Earth-observing satellite, NPP; the twin GRAIL spacecraft bound for the moon; the Juno spacecraft on its way to Jupiter; and five space shuttle missions.

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