The U.S. Air Force HiFire hypersonic flight test program with NASA and the Australian Defense Force is getting underway at the same time the Pentagon and space agency are retooling their relationship for a broad new U.S. aeronautics test strategy.

The HiFire (Hypersonic International Flight Research Experimentation) project, set for its first launch by year-end, will test 21st-century aeronautics and space technologies for application to advanced scramjet-powered space launch vehicles and weapons applications.

The HiFire payloads will dive into the atmosphere at Mach 4-8 to obtain data directly applicable to new hypersonic flight vehicles. The tests are to begin in the outback of southern Australia.

The HiFire objective is to support the new Boeing X-51 scramjet demonstrator while also building a strong base of flight test data for quick-reaction space launch development and hypersonic "quick-strike" weapons.

Both Pratt & Whitney and ATK are pursuing advanced scramjet engines that could be an element of future vehicles.

More than 100 years after the Wright brothers' first aircraft and 50 years after Sputnik, the merger of aeronautics and space technologies for high-Mach air-breathing vehicles is undergoing revival with HiFire, then the X-51, according to USAF and NASA.

"Hypersonics could be the 'next great step' in the transformation of the Air Force into a completely integrated Aerospace Force," says the Air Force Scientific Advisory Board.

Aside from the space shuttle, which began development more than 30 years ago, the field of Mach 4-8 flight test has been more the stuff of the 1960s. A special report on the pace of previous 20th century missile and space developments begins on p. 51.

Specific HiFire test objectives will encompass aerosciences, propulsion, materials and structures, sensors, space environment effects, and instrumentation and measurement techniques. The program will involve the launch of 10 42-ft.-long Terrier-Orion rockets with a liftoff thrust of 58,000 lb.

The flights will be conducted at Australia's Woomera Test Range, the largest land-based military restricted area in the world. The launchers will climb to 160 mi. altitude before pitching down to dive back into the atmosphere at speeds up to about Mach 8, where the booster payloads will obtain specific hypersonic data.