Space shuttle Columbia disaster

On February 1 2003 the Space Shuttle Columbia disintegrated upon reentering Earth’s atmosphere killing all the 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 nearly catastrophic from foam shedding, but some engineers suspected that the damage to Columbia was more serious.

Debris is visible coming from the left wing. The image was taken at Starfire Optical Range at Kirtland Air Force Base

The first indication was loss of temperature sensors and hydraulic systems on the left wing. They were followed seconds and minutes later by several other problems including loss of tire pressure indications on the left main gear and the indications of excessive structural heating. Analysis of 31 seconds of telemetry data which had initially been filtered out because of data corruption within it showed the shuttle fighting to maintain its orientation, eventually using maximum thrust from its Reaction Control System jets. The investigation focused on the foam strike from the very beginning. Incidents of debris strikes from ice and foam causing damage during take off were already well known and damaged orbiters.

Columbia debris detected by National Weather Service radar over Texas and Louisiana

After the loss of Columbia, NASA concluded that mistake during installation were the likely cause of foam loss and retrained employees to apply foam without defects. The damage had also been traced to ablating insulating material from the cryogenic fuel tank in the past. The report also concluded that:
The crew did not have time to prepare themselves. Some crew members were not wearing their safety gloves and one crew member was not wearing a helmet. New policies gave the crew more time to prepare for descent.
The crew’s safety harnesses malfunctioned during the violent descent. The harnesses on the three remaining shuttles were upgraded after the accident.
Unintended consequences of decisions contributed to the failure: the original tank white paint was removed to save 600 lb, exposing the rust-orange-colored foam, the tank foam chemical composition was altered to meet Environmental Protection Agency requirements, weakening it, upgrades to the leading edge proposed in the early 1990s were not funded because NASA was working on the later cancelled VentureStar single stage to orbit shuttle replacement.

The CAIB determined that a rescue mission though risky might have been possible provided NASA management had taken action soon enough. Normally a rescue mission is not possible due to the time required to prepare a shuttle for launch and the limited consumables of an orbiting shuttle. Atlantis was well along in processing for a planned March 1 launch and Columbia carried an unusually large quantity of consumables due to an Extended Duration Orbiter package. The CAIB determined that this would have allowed Columbia to stay in orbit until flight day 30. NASA investigators determined that Atlantis processing could have been expedited with no skipped safety checks for a February 10 launch.
NASA investigators determined that on-orbit repair by the shuttle astronauts was possible but overall considered high risk, primarily due to the uncertain resiliency of the repair using available materials and the anticipated high risk of doing additional damage to the Orbiter. Columbia did not carry the Canadarm or Remote Manipulator System, which would normally be used for camera inspection or transporting a spacewalking astronaut to the wing.
The CAIB could not determine whether a patched-up left wing would have survived even a modified re-entry and concluded that the rescue option would have had a considerably higher chance of bringing Columbia’s crew back alive if NASA would have responded soon enough.