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 Enterprise Space Shuttle Enterprise Space Shuttle "Enterprise" (Orbiter Vehicle Designation: OV-101) was the first orbiter of the Space Shuttle system. Rolled out on September 17, 1976, it was built for NASA as part of the Space Shuttle program to perform atmospheric test flights after being launched from a modified Boeing 747. It was constructed without engines or a functional heat shield, and was therefore not capable of spaceflight. Originally, "Enterprise" had been intended to be refitted for orbital flight to become the second space-rated orbiter in service. However, during the construction of , details of the final design changed, making it