On February 1, 2003, the
Space Shuttle Columbia disintegrated upon
Earth's atmosphere, killing all seven crew members. The disaster was the second fatal accident in the
Space Shuttle program after
Space Shuttle Challenger, which
broke apart and killed the seven-member crew 73 seconds after liftoff in 1986.
During the launch of
STS-107, Columbia's 28th mission, a piece of foam insulation broke off from the
Space Shuttle external tank and struck the left wing of the
orbiter. A few previous shuttle launches had seen damage ranging from minor to major from foam shedding,
 but some engineers suspected that the damage to Columbia was more serious.
NASA managers limited the investigation, reasoning that the crew could not have fixed the problem if it had been confirmed.
 When Columbia re-entered the
atmosphere of Earth, the damage allowed hot atmospheric gases to penetrate and destroy the internal wing structure, which caused the spacecraft to become unstable and break apart.
After the disaster, Space Shuttle flight operations were suspended for more than two years, as they had been after the
Challenger disaster. Construction of the
International Space Station (ISS) was put on hold; the station relied entirely on the Russian
Roscosmos State Corporation for resupply for 29 months until Shuttle flights resumed with
STS-114 and 41 months for crew rotation until
Several technical and organizational changes were made, including adding a thorough on-orbit inspection to determine how well the shuttle's
thermal protection system had endured the ascent, and keeping a designated rescue mission ready in case irreparable damage was found. Except for
one final mission to repair the
Hubble Space Telescope, subsequent shuttle missions were flown only to the ISS so that the crew could use it as a haven in case damage to the orbiter prevented safe reentry.