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Mars orbiter briefing
With two weeks until its arrival at the red planet, NASA and Lockheed Martin officials hold this Feb. 24 news conference on the Mars Reconnaissance Orbiter. The briefing explains how the MRO spacecraft will fire its engines to enter into orbit around Mars and the mission's scientific goals to examine the planet like never before.

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Lockheed's CEV plans
As part of Lockheed Martin's plans for the Crew Exploration Vehicle, the company has announced that final assembly and testing of the capsules will be performed at the Kennedy Space Center's Operations and Checkout Building. Lockheed Martin officials, Florida's lieutenant governor, the local congressman and a county economic development leader held this press conference Feb. 22 to unveil the plans.

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STS-8: Night launch
The space shuttle program performed its first dazzling nighttime launch with Challenger's August 1983 mission. A cockpit camera mounted beside commander Dick Truly captured amazing footage of night turning to day inside the shuttle from the brilliant flame of ascent. STS-8 also featured the first African-American astronaut, Guion Bluford. Challenger's astronauts tell the story of their six-day mission, which deployed an Indian satellite, used the robot arm to look at the orbiter's belly and examined the glow around the shuttle, during this narrated post-flight film.

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STS-7: America's first woman astronaut
The seventh flight of the space shuttle is remembered for breaking the gender barrier for U.S. spaceflight. Sally Ride flew into space and the history books with her historic June 1983 mission, becoming America's first woman astronaut. STS-7 also launched a pair of commercial communications spacecraft, then deployed a small platform fitted with experiments and camera package that captured iconic pictures of Challenger flying above the blue Earth and black void of space. The crew members narrate highlights from the mission in this post-flight film presentation.

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STS-6: Challenger debut
The space shuttle program became a two-orbiter fleet on April 4, 1983 when Challenger launched on its maiden voyage from Kennedy Space Center. The STS-6 mission featured the first ever spacewalk from a space shuttle and the deployment of NASA's first Tracking and Data Relay Satellite. The four astronauts narrate a movie of highlights from their five-day mission in this post-flight presentation.

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STS-121 crew press chat
Commander Steve Lindsey and his crew, the astronauts set to fly the second post-Columbia test flight, hold an informal news conference with reporters at Kennedy Space Center on Feb. 17. The crew is in Florida to examine hardware and equipment that will be carried on the STS-121 flight of shuttle Discovery.

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House hearing on NASA
NASA Administrator Mike Griffin and his No. 2, Shana Dale, appear before the House Science Committee on Feb. 16 to defend President Bush's proposed 2007 budget for the space agency. Congressmen grill Griffin and Dale about the budget's plans to cut funding for some science programs.

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Mars missions mapping polar caps, impact craters
WASHINGTON UNIVERSITY IN ST. LOUIS NEWS RELEASE
Posted: March 1, 2006

Two Mars orbiter missions - one from NASA, the other from the European Space Agency (ESA) - will open new vistas in the exploration of Mars through the use of sophisticated ground-penetrating radars, providing international researchers with the first direct clues about the Red Planet's subsurface structure.

Roger Phillips, Ph.D., Washington University in St. Louis Professor of Earth and Planetary Sciences in Arts & Sciences, is participating in both the Mars Express (ESA) and NASA's Mars Reconnaissance Orbiter (MRO) missions by lending his expertise in radar. Phillips says that the combination of the radars on the two missions will provide important and unique data sets that will directly map the structure of the upper portions of the interior of Mars.

Mars Express features an instrument called the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS); Mars Reconnaissance Orbiter's radar instrument is called the Shallow Subsurface Radar (SHARAD). Both instruments have been built primarily by the Italian Space Agency, and, says Phillips, they are complementary.

Mars Express went into orbit on Christmas Day of 2003, but the radar developed some technical problems and didn't start operating until the summer of 2005. One of the problems was making sure that the craft's long antennas would unfold without damaging the spacecraft. This necessitated a full stop, followed by many hardware and computer simulations until confidence was gained that the antennas could be deployed safely. The first data were published in the journal Science late last year, with Phillips a co-author along with approximately 30 European and American colleagues.

"One of the spectacular results of that paper is the fact that we've sounded the northern polar cap of Mars, the radar signals penetrating all the way to the bottom of the icy cap and bouncing back so that we can see right down to the cap's base, nearly two kilometers deep," Phillips says. "This result tells us that we will eventually be able to map the volume of both the northern and southern ice caps, which will provide a much better understanding of the origins and evolution of these features and the amount of water that is tied up frozen in the caps. The radar is looking inside the planet directly - that's never been done before on Mars."

The northern cap data also provide the Mars Express team with the first direct observation of how the load of the ice cap deforms the planet's underlying crust - a phenomenon called flexure. There is in fact no flexure observed within the error limits of the radar data, which means that the crust beneath the northern polar cap is very strong, says Phillips.

"That also tells us that the heat output of the planet at present is quite low. There have been theoretical models predicting this, but never a direct observation until now. "

Finding unfrozen subsurface water is a possibility, too; this is the Holy Grail of MARSIS, Phillips says.

"At the boundary of a water-rich environment we should see a very strong reflection. Whether we find such a reflector remains to be seen - we're in the early days of gathering data. Right now MARSIS is carrying out a campaign to map the structure of the southern polar cap."

Phillips says that the MARSIS radar also has mapped buried impact craters, which should revise the theory of how old the martian crust is and how it evolved.

SHARAD will likely not probe as deeply as MARSIS, but it has ten times the vertical resolution, allowing for opportunities to map detailed subsurface stratigraphy, says Phillips, who is also director of Washington University's McDonnell Center for the Space Sciences

The MRO spacecraft is now poised to go into orbit around Mars in March, and will then spend about six months aerobraking to place the spacecraft in a low circular orbit by this fall. This will mark the start of a two-year mapping campaign that NASA calls the primary science phase. Phillips is Deputy Team Leader for the MRO SHARAD experiment. The Team Leader is Roberto Seu, Ph.D., of the INFOCOM Department at the University of Rome, La Sapienza, Italy.

"I think that SHARAD will be an excellent mapper of the sedimentary layers on Mars, and that will help us better understand the water history of the planet, "Phillips says. "One of my hopes is to connect what SHARAD maps in the subsurface in the Terra Meridiani area to the sulfate-rich stratigraphy that has been seen there by the Mars Exploration Rover (MER) Opportunity. This will help place the local stratigraphy at the MER landing site into a more regional context and help refine hypotheses for the origins of these enigmatic sedimentary rocks."