When the Hyper-X flies, it will be the first time a non-rocket engine has powered a vehicle in flight at hypersonic speeds -- speeds above Mach 5, equivalent to about one mile per second or approximately 3,600 miles per hour at sea level. A booster rocket will carry each experimental vehicle to its flight-test speed and altitude, where it will be launched to fly under its own power.
Program managers plan to demonstrate hydrogen-powered, "air- breathing" propulsion systems that could ultimately be applied in vehicle types ranging from hypersonic aircraft to reusable space launchers.
A rocket carries its own oxygen for combustion. An air- breathing vehicle, the experimental Hyper-X, will burn oxygen in the air scooped from the atmosphere. Because of this, air- breathing hypersonic vehicles should carry more payload and/or offer longer range than equivalent rocket-powered systems.
Four flights are planned -- one each at Mach 5 and 7 and two at Mach 10. The Mach 7 flight comes first early in fiscal year 1999. The flight tests will be conducted within the Western Test Range off the coast of southern California.