Technical and Programmatic Consequences of a Hypersonic Vehicle Flight Test Ban
The hypersonic vehicle (HV) is defined as any vehicle capable of traveling at or above five times the local speed of sound (Mach 5). Development of hypersonic flight has been pursued since the late 1950s, especially for reentry of missile warheads and returning orbiting spacecraft. Although considerable progress has been made since then, air- breathing and gliding hypersonic flight remains in the development and testing phase. Concerns have been raised, however, about continued HV flight tests because of HV's potential military use, which has the potential to encourage hair-trigger tactics that would increase crisis instability. In recent years, non-governmental organizations have called for a ban on HV flight testing for the primary purpose of halting continued development of the HV as a weapon. The emphasis on banning flight tests is due to its vital role in aerospace programs. Without it, significant technical uncertainties remain, creating safety and reliability issues that would discourage commercial development. Although the cost and time involved in flight tests have already spurred the use of other test methods, none can completely reproduce the flight test environment. Flight tests are important for reasons such as generating data unique to flight test environments to use in validating models and verifying ground test data, identifying unanticipated problems, and reducing risk. Commercial HV technology development today depends on advancements in four areas: propulsion; aerodynamics; critical guidance, navigation and control; and thermal management. This report summarizes the ramifications on HV technology development if flight tests were banned.