<DIV>Designed between 1969 and 1972 and first flown into space in 1981, the NASA Shuttle will have flown almost 140 missions by the time it is retired in 2011. David Baker describes the origin of the reusable launch vehicle concept during the 1960s, its evolution into a viable flying machine in the early 1970s, and its subsequent design, engineering, construction, and operation. The Shuttle&rsquo;s internal layout and systems are explained, including the operation of life support, electrical-power production, cooling, propulsion, flight control, communications, landing, and avionics systems.</div>