Tags: Artificialsatellite, Satellite.
STS-400 was the Space Shuttle contingency support (Launch On Need) flight that would have been launched using Space Shuttle Endeavour if a major problem occurred on Space Shuttle Atlantis during STS-125 the final Hubble Space Telescope servicing mission (HST SM-4).Due to the much lower orbital inclination of the HST compared to the ISS the shuttle crew would have been unable to use the International Space Station as a safe haven and NASA would not have been able to follow the usual plan of recovering the crew with another shuttle at a later date.
