NASA tests scramjet

The US space agency will attempt to fly its experimental hypersonic research aircraft, the X-43A, this Saturday. The unpiloted 3.7m-long vehicle uses a scramjet to reach a design speed in excess of Mach 7, more than 8,000 km/h (5,000 mph).

Scramjets burn hydrogen but take their oxygen from the air which is forced into the engine at very high speed.

It is hoped this technology could one day dramatically reduce the length of long-haul passenger flights and make it much cheaper to launch space payloads.

NASA will just want its latest experiment to complete its goals without incident. The first attempt to fly an X-43A ended in the destruction of the vehicle when its launch system failed, report BBC.

It is to last just 10 seconds, but researchers say this brief firing of a new kind of jet engine could be the first step toward revolutionizing high-speed air and space travel. This could be the beginning of a revolution in aviation," Vincent L. Rausch of NASA's Langley Research Center in Hampton, Va., said Wednesday in an interview. "We're ready to go and looking forward to getting this flight off."

The flight plan calls for a modified NASA B-52 bomber to drop the 2,700-pound X-43A, attached to a booster rocket, from 40,000 feet above the Navy's Pacific test range off the California coast at 4 p.m. Researchers have tested scramjet, or supersonic-combustion ramjet, engines in laboratories for decades, but none have been flown successfully. Conventional turbojets work by concentrating air with fan-like blades in a compressor, combining it with fuel and burning the mixture to produce thrust. Faster speeds can be attained using ramjets, which forgo the compressor and use a specially shaped inlet to concentrate air for burning when moving at high speed.

Airplanes powered by scramjets, engineers believe, could travel at thousands of miles per hour. And space rockets, instead of carrying heavy liquid oxygen to burn with their fuel, could use scramjets to scoop it out of the atmosphere and carry more cargo into orbit, informed nytimes.com