The US Air Force was forced to accept the shuttle, and the cancellation of their expendable launch vehicle programs, by the Nixon, Ford, Carter, and early Reagan administrations. Only after the explosion of the Challenger was the fallacy of NASA's claim that the shuttle would produce cheap and reliable access to space exposed. In fact it provided neither, and the Air Force was allowed to develop a new generation of expendable launch vehicles to use in place of the shuttle. One aspect of this antagonism was reflected in shuttle astronaut crew selections. Paradoxically the USAF provided little support to its astronauts. The US Navy, on the other hand, with no major stake in competing for the means of access to space, kept good relations with NASA. Its astronauts were feted and publicized at the highest levels of the service. As a result, Navy pilots received by far the larger share of shuttle commander assignments throughout the program.