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 Atlantis Space Shuttle Atlantis Space Shuttle "Atlantis" (Orbiter Vehicle Designation: OV‑104) is a Space Shuttle orbiter vehicle belonging to the National Aeronautics and Space Administration (NASA), the spaceflight and space exploration agency of the United States. Constructed by the Rockwell International company in Southern California and delivered to the Kennedy Space Center in Eastern Florida in April 1985, "Atlantis" is the fourth operational and the second-to-last Space Shuttle built. Its maiden flight was STS-51-J from 3 to 7 October 1985. "Atlantis" embarked on its 33rd and final mission, also the final mission of a space shuttle, STS-135, on 8 July 2011.