Space Shuttle orbiter its maiden flight in 1977. An unpowered glider, it was carried by a modified Boeing 747 airliner called the Shuttle Carrier Aircraft and released for a series of atmospheric test flights and landings. "Enterprise" was partially disassembled and retired after completion of critical testing. The remaining orbiters were fully operational spacecraft, and were launched vertically as part of the Space Shuttle stack. "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 shortly after launch. "Endeavour" was built
Space Shuttle program been canceled. in the 2010s, two major programs for human spaceflight were Commercial Crew Development and the Space Launch System with the Orion capsule. Kennedy Space Center Launch Complex 39 was, for example, used to launch a Falcon Heavy rocket. The Space Shuttle program has been criticized for failing to achieve its promised cost and utility goals, as well as design, cost, management, and safety issues. Others have argued that the Shuttle program was a step backwards from the Apollo Program, which, while extremely dangerous, accomplished far more scientific and space exploration endeavors than the Shuttle ever could. After both