Space shuttle Discovery lifts off from Launch Pad 39B at the Kennedy Space Center, Tuesday, July 26, 2005, at Cape Canaveral, Fla. (AP Photo/David F. Martin)
Here is a look at key developments in NASA's return to space:
Feb. 1, 2003: Shuttle Columbia breaks apart as it heads for a landing in Florida, killing all seven astronauts. NASA says it will appoint a panel to investigate the cause.
Feb. 2, 2003: NASA names retired Navy Adm. Harold W. Gehman Jr. to lead the Columbia Accident Investigation Board, an independent commission.
June 13, 2003: Return To Flight Task Group is appointed to oversee safety improvements.
Aug. 26, 2003: The accident investigation board releases its report on the shuttle accident, saying the cause was a large chunk of foam insulation that snapped off the external fuel tank at launch and knocked a hole in the left wing. A major contributing factor was a flawed safety culture that squelched warnings from lower-level employees. The board recommends 29 improvements, 15 to be completed before sending shuttles back into space.
Jan. 14, 2004: President Bush announces a new exploration policy for NASA, setting the shuttle's retirement for 2010 and a return to the moon by astronauts by 2020.
Dec. 13, 2004: NASA Administrator Sean O'Keefe announces he is resigning. He is the leading candidate for the chancellor's job at Louisiana State University, which he ends up getting.
April 13, 2005: Michael Griffin, head of the space department at Johns Hopkins University's Applied Physics Laboratory, is appointed NASA administrator.
April 29, 2005: NASA scraps plans for a shuttle flight in May because of concerns over ice buildup on the external fuel tank, and bumps the mission to July.
May 12, 2005: Griffin makes a case before a Senate subcommittee for speeding up development of the shuttle replacement, the "crew exploration vehicle." He wants the new spacecraft flying as soon as possible in the next decade, to avoid a gap once the shuttle is retired in 2010.
June 27, 2005: A safety advisory panel concludes that NASA failed to make three of 15 return-to-flight improvements recommended by the Columbia accident investigators.
June 30, 2005: NASA formally sets July 13 as the new launch date.
July 13, 2005: Launch for shuttle Discovery is delayed in the final stages of the countdown because of a fuel tank sensor problem.
July 26, 2005: Discovery is ready for launch.
Mission Details (Wikipedia)
Space Shuttle Discovery launches from Kennedy Space Center, launch pad 39-B 26-July-2005 @ 10:39 AM EDT (1439 UTC) with a 12-day mission. Landing planned for 07-August-2005 @ 5:46 AM EDT (0946 UTC). Orbit altitude 122 nautical miles (226 km). Orbit inclination 51.6 degrees.