Editing Space Shuttle program (section)

===STS-51-L (''Challenger'', 1986)===
{{main|Space Shuttle Challenger disaster}}
[[File:Challenger explosion.jpg|thumb|right|In 1986, ''Challenger'' disintegrated one minute and 13 seconds after liftoff.]]
Close-up video footage of ''Challenger'' during its final launch on January 28, 1986, clearly shows that the problems began due to an [[Space Shuttle Challenger disaster|O-ring failure]] on the right solid rocket booster (SRB). The hot plume of gas leaking from the failed joint caused the collapse of the external tank, which then resulted in the orbiter's disintegration due to high aerodynamic stress. The accident resulted in the loss of all seven astronauts on board. ''[[Space Shuttle Endeavour|Endeavour]]'' (OV-105) was built to replace ''Challenger'' (using structural spare parts originally intended for the other orbiters) and delivered in May 1991; it was first launched a year later.

After the loss of ''Challenger'', NASA grounded the Space Shuttle program for over two years, making numerous safety changes recommended by the [[Rogers Commission Report]], which included a redesign of the SRB joint that failed in the ''Challenger'' accident. Other safety changes included a new escape system for use when the orbiter was in controlled flight, improved landing gear tires and brakes, and the reintroduction of pressure suits for Shuttle astronauts (these had been discontinued after [[STS-4]]; astronauts wore only coveralls and oxygen helmets from that point on until the ''Challenger'' accident). The Shuttle program continued in September 1988 with the launch of ''Discovery'' on [[STS-26]].

The accidents did not just affect the technical design of the orbiter, but also NASA.<ref name="history.nasa.gov"/>
Quoting some recommendations made by the post-''Challenger'' Rogers commission:<ref name="history.nasa.gov"/>
{{Blockquote|<poem>
'''Recommendation I''' – The faulty Solid Rocket Motor joint and seal must be changed. This could be a new design eliminating the joint or a redesign of the current joint and seal. ... the Administrator of NASA should request the National Research Council to form an independent Solid Rocket Motor design oversight committee to implement the Commission's design recommendations and oversee the design effort.
'''Recommendation II''' – The Shuttle Program Structure should be reviewed. ... NASA should encourage the transition of qualified astronauts into agency management Positions.
'''Recommendation III''' – NASA and the primary shuttle contractors should review all Criticality 1, 1R, 2, and 2R items and hazard analyses.
'''Recommendation IV''' – NASA should establish an Office of Safety, Reliability and Quality Assurance to be headed by an Associate Administrator, reporting directly to the NASA Administrator.
'''Recommendation VI''' – NASA must take actions to improve landing safety. The tire, brake and nosewheel system must be improved.
'''Recommendation VII''' – Make all efforts to provide a crew escape system for use during controlled gliding flight.
'''Recommendation VIII''' – The nation's reliance on the shuttle as its principal space launch capability created a relentless pressure on NASA to increase the flight rate ... NASA must establish a flight rate that is consistent with its resources.
</poem>}}