Criticism of the Space Shuttle program (approximately $ per pound adjusting for inflation to 2011). It failed in the goal of achieving reliable access to space, partly due to multi-year interruptions in launches following Shuttle failures. NASA budget pressures caused by the chronically high NASA Space Shuttle program costs have eliminated NASA manned space flight beyond low earth orbit since Apollo, and severely curtailed use of unmanned probes. NASA's promotion of and reliance on the Shuttle slowed domestic commercial expendable launch vehicle (ELV) programs until after the 1986 "Challenger" disaster. "Space Transportation System" (NASA's formal name for the overall Shuttle program) was created to transport crewmembers
Space Shuttle two different upper stages developed for the STS (single-stage Payload Assist Module or two-stage Inertial Upper Stage). The Space Shuttle was stacked in the Vehicle Assembly Building, and the stack mounted on a mobile launch platform held down by four frangible nuts on each SRB, which were detonated at launch. The Shuttle stack launched vertically like a conventional rocket. It lifted off under the power of its two SRBs and three main engines, which were fueled by liquid hydrogen and liquid oxygen from the ET. The Space Shuttle had a two-stage ascent. The SRBs provided additional thrust during liftoff and