NASA has set Saturday, March 27, for the flight of its
experimental X-43A research vehicle. The unpiloted
12-foot-long vehicle, part aircraft and part spacecraft, will be
dropped from the wing of a B-52 aircraft, boosted to nearly 100,000
feet by a booster rocket and released over the Pacific Ocean to
briefly fly under its own power at seven times the speed of sound
(almost 5,000 mph).
The flight is part of the Hyper-X program, a research effort
designed to demonstrate alternate propulsion technologies for
access to space and high-speed flight within the atmosphere.
It will provide unique “first time” data on hypersonic
air-breathing engine technologies that have large potential
Hyper-X is inherently a high-risk program. No vehicle has
ever flown at hypersonic speeds powered by an air-breathing
scramjet engine. In addition, the rocket boost and subsequent
separation from the rocket to get to the scramjet test condition
have complex elements that must work properly for the mission to be
The $250 million program began with conceptual design and wind
tunnel work with a scramjet engine in 1996. In a scramjet
(supersonic-combustion ramjet), the flow of air through the engine
remains supersonic, or greater than the speed of sound, for optimum
engine efficiency and vehicle speed.
There are few or no moving parts in a scramjet engine, but
achieving proper ignition and combustion in a matter of
milliseconds proved to be an engineering challenge of the highest
order. After a series of successful wind tunnel tests,
however, NASA is ready to demonstrate that air-breathing scramjets
work in flight.
Researchers believe these technologies may someday offer more
airplane-like operations and other benefits compared to traditional
rocket systems. Rockets provide limited throttle control and
must carry heavy tanks filled with liquid oxygen, necessary for
combustion of fuel. An air-breathing engine, like that on the
X-43A, scoops oxygen from the air as it flies. The weight savings
could be used to increase payload capacity, increase range or
reduce vehicle size for the same payload.
The X-43A will fly in the Naval Air Warfare Center Weapons
Division Sea Range over the Pacific Ocean off the coast of Southern
California. After booster burnout, the 2,800-pound,
wedge-shaped craft will separate and fly on its own to perform a
preprogrammed set of tasks. After an approximate 10 second
test firing of the engine, the X-43A will glide through the
atmosphere conducting a series of aerodynamic maneuvers for up to
six minutes on its way to splashdown.
This will be the second flight in the X-43A project. On
June 2, 2001, the first X-43A vehicle was lost moments after
release from the wing of the B-52. Following booster ignition, the
combined booster and X-43A vehicle deviated from its flight path
and was deliberately destroyed. Investigation into the mishap
showed that there was no single contributing factor, but the root
cause of the problem was identified as the control system of the
For this flight, the B-52 will carry the booster with the
attached X-43A to 40,000 feet before its release, versus the 23,000
feet of the first attempt. The booster will carry the X-43A
research vehicle to approximately the same test conditions --
altitude and speed -- as planned for the first flight.
NASA’s Langley Research Center, Hampton, Va., and Dryden
Flight Research Center, Edwards, Calif., jointly conduct the
Additional images, video clips, and additional information about
the project are available on the Internet at:
NASA television will carry the flight and the post-flight news
briefing live. NASA TV is available on AMC 9, TRANSPONDER 9C,
85 degrees west longitude, vertical polarization with a frequency
of 3880 MHz and audio of 6.8 MHz.