Space Shuttle Challenger disaster cause to the accident. After the accident, NASA attempted to aim at a more realistic shuttle flight rate: it added another orbiter, "Endeavour", to the space shuttle fleet to replace "Challenger", and it worked with the Department of Defense to put more satellites in orbit using expendable launch vehicles rather than the shuttle. In August 1986, President Reagan also announced that the shuttle would no longer carry commercial satellite payloads. After a 32-month hiatus, the next shuttle mission, STS-26, was launched on September 29, 1988. Although changes were made by NASA after the "Challenger" accident, many commentators have argued that
Space Shuttle Columbia disaster crew of two. Less than a year after the accident, President Bush announced the Vision for Space Exploration, calling for the space shuttle fleet to complete the ISS, with retirement by the year 2010 following the completion of the ISS, to be replaced by a newly developed Crew Exploration Vehicle for travel to the Moon and Mars. NASA planned to return the space shuttle to service around September 2004; that date was pushed back to July 2005. On July 26, 2005, at 10:39 am EST, Space Shuttle "Discovery" cleared the tower on the "Return to Flight" mission STS-114, marking the