The first American spacewalk, conducted in 1965 by Gemini 4 astronaut Ed White, is seen during a screening of a selection from over 100 hours of high definition archival footage of space travel that Discovery Communications is returning to NASA, on Capitol Hill in Washington May 6, 2008. REUTERS/Larry Downing (UNITED STATES) 

Astronaut Sory Musgrave, anchored on the Remote Manipulator System arm, prepares to install protective covers on the magnetometers of the Hubble Space Telescope December 9. Astronaut Jeffrey Hoffman (bottom of frame) assists as the two wrap up five days of spacewalks by Shuttle astronauts to service the telescope. The Earth is in the background 

Space shuttle Discovery astronaut Mark Lee teams with Steven Smith (out of frame but reflected in Lee's helmet visor) during their spacewalking service mission on the Hubble Space Telescope February 16. The astronauts finished their repairs on the Hubble February 18 and it was sent back to orbit February 19. 

Astronaut Mark Lee floats free in space around the earth while testing a new jetpack rescue device (SAFER) September 16th. Lee and his colleague Col. Carl Meade from the Space Shuttle Discovery tested the device in the first untethered spacewalk by NASA astronauts in ten years 

Mir space station commander Anatoly Solovyov cuts through the insulation cover of the Spektr modul with a special hammer-like instrument during six hours work in outer space September 6. Solovyov and NASA researcher Michael Foale went on a risky spacewalk trying to repair damage caused by a cargo tug that collided with the Mir station in June. 

View of astronauts Carl Meade, floating untethered and Mark Lee anchored to the Space Shuttle Discovery's robot arm. They test NASA's new jetpack rescue system, known by its acronym SAFER, some 130 nautical miles above Earth seen in background September 16 in this photograph released September 28. The two took turns wearing the device in the first untethered spacewalk by NASA astronauts in ten years 

Astronaut Kathryn Thornton, on the end of the Shuttle Endeaovour's Remote Manipulator System, hovers over servicing equipment for the Hubble Space Telescope December 6 during the second spacewalk of the Shuttle's eleven-day mission