After about eight minutes of flight, the orbiter's main engines shut down; the external tank is then jettisoned and burns up as it reenters the atmosphere. The orbiter meanwhile enters orbit after a short burn of its two small Orbiting Maneuvering System (OMS) engines. At this time, its top speed is an amazing 8,000 meters per second! To return to earth, the orbiter turns around, fires its OMS engines to reduce speed, and, after descending through the atmosphere lands like a glider.

After four orbital test flights (1981-1982) of the space shuttle Columbia, operational flights began in November of 1982. On January 28, 1986, a shuttle exploded shortly after takeoff, killing all seven astronauts. Shuttle flights were suspended until September 1988, while design problems were corrected, and then resumed on a more conservative schedule; NASA was forced to reemphasize expendable rockets to reduce the cost of placing payloads in space. By the end of 2000, 102 missions had been completed and five different orbiters had been seen in service.