Why did NASA stick with the space shuttle so long?
Though the space shuttle is viewed as futuristic, its design is three decades old. The shuttle’s main engines, first tested in the late 1970s, use hundreds more moving parts than do new rocket-motor designs. The fragile heat-dissipating tiles were designed before breakthroughs in materials science. Until recently, the flight-deck computers on the space shuttle used old 8086 chips from the early 1980s, the sort of pre-Pentium electronics no self-respecting teenager would dream of using for a video game. Most important, the space shuttle was designed under the highly unrealistic assumption that the fleet would fly to space once a week and that each shuttle would need to be big enough to carry 50,000 lbs. of payload. In actual use, the shuttle fleet has averaged five flights a year; this year flights were to be cut back to four. The maximum payload is almost never carried. Yet to accommodate the highly unrealistic initial goals, engineers made the shuttle huge and expensive. The Soviet sp
