The X-51A WaveRider is expected to fly as fast as 4,000 mph (Mach 6). But in its first flight Dec. 9, it stayed firmly tucked under the wing of a B-52H Stratofortress.
The WaveRider’s first hypersonic test flight, set for mid-February 2010.
On that mission, a B-52 will release the WaveRider 50,000 feet over the Pacific Ocean. A solid rocket booster will ignite and accelerate the WaveRider to Mach 4.5; then, its supersonic combustion ramjet, or scramjet, propulsion system will kick in for about five minutes to take it all the way to Mach 6. The longest scramjet test to date lasted only 10 seconds.
The X-51A demonstration vehicle is intended to show that scramjets can fly for long durations at high speeds without overheating. The WaveRider could be used for intelligence-gathering and bombing missions in addition to space launches.