NASA's hypersonic scramjet project suffered a major setback on June 2 when its unpiloted X-43A research aircraft was destroyed shortly after release from a B-52.

According to NASA: "Following pre-launch countdown and separation from the B-52, a malfunction occurred about five seconds after ignition of the Pegasus motor that caused the Hyper-X stack (Hyper-X vehicle and booster) to depart from controlled flight. The debris impacted within the pre-cleared range impact area in the Pacific Ocean."

The Hyper-X vehicle is a prototype hypersonic aircraft. It is powered by a 'scramjet'. which ducts air directly from the atmosphere, mixing it with hydrogen before combustion. The forward speed of the vehicle provides compression, thereby eliminating the need for conventional jet engine turbines. The speed of the airflow through the engine remains supersonic throughout. The Pegasus booster used for the NASA test was intended to accelerate the vehicle to a sufficient speed for the scramjet to kick in.

Ramjets (where the airflow through the engine is sub-sonic), have already been successfully tested. The mechanical simplicity of the design, and the added bonus of not having to carry - unlike a rocket - oxygen tanks seemed to bode well for the scramjet. It now remains to be seen whether NASA can maintain the credibility of the technology. ®

Related links

NASA jet to hit Mach 10
NASA press release

Bootnote

It has been a bad - and sad - weekend for aviation generally. On Sunday, the 40-year-old pilot of a 1942 Bell King Cobra was killed when the aircraft dived vertically into the ground at the Biggin Hill airshow in the UK. The incident followed another tragedy at the event on Saturday, when both crew members of a 1950s De Havilland Vampire died in an unexplained crash.