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 main engine to the four-engine configuration and its position in-plane with the SLS booster exhaust nozzles. New ablative insulation and heaters were to be tested during the series. Following these series of tests, four more engines are planned to enter a new test cycle. A new series of tests designed to evaluate performance in SLS use cases was initiated in 2017. Space Shuttle main engine The Aerojet Rocketdyne RS-25, otherwise known as the Space Shuttle main engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is planned to be used on its successor, the Space