Visitors to the Intrepid Sea, Air and Space museum watch as NASA announces that the museum will receive the retired space shuttle Enterprise on a 40 foot long video wall, Tuesday, April 12, 2011 in New York. Shuttles will be going to the Smithsonian Institution, the Intrepid Sea, Air and Space Museum in New York, the Kennedy Space Center in Florida and the California Science Center in Los Angeles. (AP Photo/Mary Altaffer)
This March 28, 2011 image provided by NASA shows composited images from Swift's Ultraviolet/Optical and X-ray telescopes of a gamma-ray explosion designated GRB 110328A. Scientists say this blast is unusual because the effects are long-lasting. More than a week later, they continue to see high-energy radiation spiking and fading at the source. Flaring from such an event usually lasts a couple of hours. (AP Photo/NASA, Swift, Stefan Immler)
This image provided by NASA is the first ever obtained from a spacecraft in orbit about the Solar System's innermost planet, Mercury. The image was captured early this morning, at 5:20 a.m. EDT,Tuesday March 29, 2011. The dominant rayed crater in the upper portion of the image is Debussy. The bottom portion of this image is near Mercury's south pole and includes a region of Mercury's surface not previously seen by spacecraft. On March 17, 2011 (March 18, 2011, UTC), MESSENGER became the first spacecraft to orbit the planet Mercury. (AP Photo/NASA)
FILE - This undated file image provided by NASA shows the surface of Mars as seen from the stuck Mars rover, Spirit. The prospect of ever hearing from Spirit is fading after it failed to respond to repeated calls from Earth since a little over a year ago. NASA officials say the fact that Spirit hasn't called home suggests something is more seriously wrong than just a power issue. (AP Photo/NASA, File)
FILE - In this Jan. 11, 1999 file photo, workers at Kennedy Space Center in Florida watch as the Stardust spacecraft is lowered. NASA on Thursday, March 24, 2011 ordered its comet-hunting Stardust probe to burn its remaining fuel, setting off a series of events that will shut down the spacecraft after a 12-year career (AP Photo/NASA, File)
This image provided by NASA, shows a image NASA’s Messenger probe made when it flew by Mercury in September 2009. It's a close-up of its pockmarked southern hemisphere, an area that had never been seen before. Messenger will enter into Mercury’s orbit on March 17, 2011. Earth is about to get better acquainted with its oddball planetary cousin. (AP Photo/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)
In this March 15, 2011 photo provided by NASA, astronaut Scott Kelly, Expedition 26 commander, right, poses with Robonaut 2, the dexterous humanoid astronaut helper, in the Destiny laboratory of the International Space Station. (AP Photo/NASA)
In a photo provided by NASA, Expedition 26 Commander Scott Kelly wears a blue wrist band that has a peace symbol, a heart and the word "Gabby" to show his love of his sister-in-law, U.S. Rep. Gabrielle Giffords, as he rest onboard a Russian Search and Rescue helicopter shortly after he and fellow crew members Oleg Skripochka and Alexander Kaleri landed in their Soyuz TMA-01M capsule near the town of Arkalyk, Kazakhstan on Wednesday, March 16, 2011. NASA astronaut Kelly, and Russian cosmonauts Skripochka and Kaleri are returning from almost six months onboard the International Space Station where they served as members of the Expedition 25 and 26 crews. (AP Photo/NASA, Bill Ingalls)
In this photo provided by NASA, Expedition 26 Commander Scott Kelly wears a blue wristband that has a peace symbol, a heart and the name "Gabby" to show his support for his sister-in-law, U.S. Rep. Gabrielle Giffords, as he rested onboard a Russian Search and Rescue helicopter shortly after he and fellow crew members Oleg Skripochka and Alexander Kaleri landed in their Soyuz TMA-01M capsule near the town of Arkalyk, Kazakhstan, on Wednesday, March 16, 2011. NASA Astronaut Kelly, Russian Cosmonauts Skripochka and Kaleri are returning from almost six months onboard the International Space Station where they served as members of the Expedition 25 and 26 crews. (AP Photo/NASA, Bill Ingalls) MANDATORY CREDIT
