"Columbia" was the first space-worthy orbiter, and made its inaugural flight in 1981. "Challenger", "Discovery", and "Atlantis" followed in 1983, 1984, and 1985 respectively. In 1986, "Challenger" was destroyed in an accident in 1986 shortly after its 10th launch. "Endeavour" was built as "Challenger"s successor, and was first launched in 1992. In 2003, "Columbia" was destroyed during re-entry, leaving just three remaining orbiters. "Discovery" completed its final flight on March 9, 2011, and "Endeavour" completed its final flight on June 1, 2011. "Atlantis" completed the final Shuttle flight, STS-135, on July 21, 2011.