NASA jet hit speeds of 5,000mph

Three years after its first test flight ended in an explosion, NASA yesterday successfully launched an experimental jet that the agency believes reached a record-setting speed of about 5,000mph.

The unpiloted X-43A made an 11-second powered flight, then went through some twists and turns during a six-minute glide before plunging into the Pacific Ocean about 400 miles off the California coast.

“It was fun all the way to Mach 7,” said Joel Sitz, project manager at NASA's Dryden Flight Research Centre.

Flight engineer Lawrence Huebner said preliminary data indicated the needle-nosed jet reached a maximum speed of slightly over seven times the speed of sound, or about 5,000 mph, after a rocket boosted it to about 3,500 mph.

Huebner said it was the first time an “air-breathing” jet had ever travelled so fast. The rocket-powered X-15 reached Mach 6.7 in 1967.

“It’s a great way to end, certainly all the sweeter because of the challenges we’ve had to step up to and overcome through the life of this project,” said Griffin Corpening, Dryden’s chief engineer on the project.

Engineers have pursued scramjet technology because it could allow rocket-speed travel but with considerable savings in weight.

Rockets must carry their own oxygen to combust the fuel they carry aboard scramjets can scoop it out of the atmosphere.

In scramjets, oxygen is rammed into a combustion chamber where it mixes with fuel and spontaneously ignites.

To work, the engine must be travelling at about five times the speed of sound – requiring an initial boost that only a rocket can provide.