The surface of Mars is seen from the NASA’s Exploration Rover Spirit on Jan. 28, 2004. The prospect of ever hearing from the stuck Mars rover Spirit is fading after it failed to respond to repeated calls from Earth. (AP-Yonhap News/NASA)
The surface of Mercury was captured by Messenger, the first spacecraft to orbit the planet Mercury on March 29, 2011. (AP-Yonhap News/NASA)
NASA’s Messenger probe captured the southern hemisphere of Mercury when it flew by the planet in September 2009. (AP-Yonhap News/NASA)
NASA/ESA's Hubble Space Telescope captures Saturn with the rings edge-on and both poles in view, offering view of its fluttering auroras on March 22, 2011. (NASA)
The full moon is seen as it rises near the Lincoln Memorial, Saturday, March 19, 2011, in Washington. The full moon was called a "Super Perigee Moon" since it was at it's closest to Earth in 2011. (AP-Yonhap News/NASA)
Russian space agency rescuers help Russian cosmonaut Alexander Kaleri shortly after their landing near the town of Arkalyk in northern Kazakhstan, Wednesday, March 16, 2011. NASA astronaut Scott Kelly and two Russian cosmonauts landed safely Wednesday in the snowy expanses of central Kazakhstan after spending a five-month stint on the International Space Station. (AP-Yonhap News)
Portions of the Martian surface are seen in unprecedented detail from the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter on Jan. 14, 2011. (AP-Yonhap News)
An enhanced photo image of Mercury from NASA’s Messenger probe (AP-Yonhap News/NASA)
