NASA Readies Flight of Fastest Plane

E D W A R D S  A I R F O R C E  B A S E, Calif. June 1 -- NASA will send asurfboard-shaped jet zipping over the Pacific Ocean this weekend onwhat is planned to be record-breaking hypersonic flight at seventimes the speed of sound.

The unmanned X-43A is scheduled to make its maiden flightSaturday afternoon, when a B-52 will carry it and a Pegasus rocketover the ocean, where the rocket will ignite and boost theexperimental plane to approximately 100,000 feet before releasing it.

The X-43A will then fire its specialized engine — called ascramjet — and fly under its own power for 10 seconds, coveringabout 17 miles. It will then coast to an impact inthe water.

Air-Breathing

The plane should reach speeds approaching Mach 7 during itsfleeting flight, besting the Mach 6.7 record set by therocket-powered X-15 in 1967.

Although a rocket will bump the X-43A to its initial velocity,it will rely on an air-breathing engine while flying independently.The plane will carry a small amount of hydrogen for fuel, but scoopoxygen out of the atmosphere to combust it. Conventional rocketsmust carry both fuel and an oxidant.

The flight will mark the first time an air-breathing plane fliesat hypersonic speeds, or faster than Mach 5.

The $185 million experimental project aims to fly three ofthe planes over the next 18 months. Although none of the planeswill be recovered, data collected during the flights will be usedto build future planes perhaps 200 feet in length. Thefirst piloted prototypes may fly by 2025.

Backers of the technology say air-breathing hypersonicpropulsion could help space travel by reducing the need to carry anoxidant aboard, freeing up room for extra cargo.