The Mars Exploration Rovers "Spirit" and "Opportunity" were sent to Mars for what was planned to be a 90 day mission. 5 years later they are still roving the surface of Mars, making new discoveries almost every day.

The Galaxy Evolution Explorer (GALEX) is an orbiting space telescope observing galaxies in ultraviolet light across 10 billion years of cosmic history.

Expedition 18 Flight Engineer Greg Chamitoff makes a move in the Earth vs. Space Chess match after his return to Earth.

Archival footage shows the Apollo astronauts viewpoint during their moon landing in 1971.

NASA's Fermi spacecraft orbits about 300 miles above Earth, scanning and imaging for gamma rays that scientists say hold answers to how the universe works.

This week in space: Phoenix Lives, Columbia Accident Report, International Year of Astronomy, Ice on the Moon

NASA rovers Spirit and Opportunity may still have big achievements ahead as they approach the fifth anniversaries of their memorable landings on Mars.

Aboard the International Space Station, Expedition 18 Commander Mike Fincke and Flight Engineers Sandy Magnus and Yury Lonchakov downlinked a message on Dec. 29, 2008.

A look back at This Week at NASA's top stories chronicling the achievements of the agencies men and women in 2008. Part 6 of 6.

A look back at This Week at NASA's top stories chronicling the achievements of the agencies men and women in 2008. Part 5 of 6.