Pegasus-Derivative Hyper-X Launch Vehicle to Accelerate Air-Breathing Scramjet to Mach Advanced X-Vehicle Unveiled Today at NASA Dryden Flight Research Center

Orbital Sciences Corporation’s
(NYSE: ORB) participation in critical aerospace research programs was
recognized today as the National Aeronautics and Space Administration’s
(NASA’s) hypersonic scramjet test vehicle, the X-43A “Hyper-X,” was introduced
to the media at Dryden Flight Research Center in Edwards, California.
Orbital’s Launch Systems Group (LSG) is building three Pegasus-derivative
rockets for the Hyper-X program, a five-year, $200 million effort to
demonstrate future hypersonic propulsion and airframe technologies.
Each
modified Pegasus rocket will accelerate a small, unmanned Hyper-X research
vehicle (the X-43A) to a predetermined altitude and Mach number, where it will
separate itself to conduct its mission.
The Hyper-X research vehicles were
developed by Micro Craft Inc. of Tullahoma, Tennessee and the program is
administered jointly by NASA’s Dryden and Langley Research Centers.

NASA is using the Hyper-X vehicles to test propulsion technologies that
could be applied to future reusable space launchers and hypersonic aircraft.
While vehicles with conventional rocket engines carry oxygen on board, the
air-breathing Hyper-X vehicles ingest and compress oxygen from the atmosphere
using the vehicle airframe.
This type of propulsion system could potentially
increase payload capacity on future vehicles since no onboard supply of
oxidizer would be required.

At today’s event, the Hyper-X government/industry team applauded recent
program successes, including mating of the Hyper-X research vehicle and
Pegasus-based booster in January, completion of the flight readiness review in
February, and a successful combined systems and taxi test in March.
Other
significant project milestones are rapidly approaching with a captive carry
flight scheduled for late April and the first flight test planned for May.
Two additional flight tests will occur in 2001 and 2002.

In comments to the audience of media, government and industry
representatives, Mr. Phillip Joyce, Orbital’s Hyper-X Program Manager, said,
“Orbital is proud to be a key part of this NASA/industry team that is pushing
the envelope of atmospheric flight.
The Hyper-X Launch Vehicle represents an
application of Pegasus technology envisioned by NASA and Orbital since the
development of Pegasus in the late 1980’s.
In addition to space launch,
Pegasus is ideally suited to hypersonic research and development, and this
feature has been recognized by NASA.”

The Hyper-X Launch Vehicle builds on technology and operational methods
developed on Pegasus, as well as on methods for developing unique, one-of-a-
kind launch vehicles in LSG’s past suborbital rocket programs.
Since 1990,
the three-stage Pegasus rocket has conducted 30 launches and placed over 70
satellites into orbit from six separate sites worldwide.
For the Hyper-X
Launch Vehicle, the Pegasus rocket’s second and third stages have been
eliminated, as has the fairing, which is normally used to protect satellite
payloads.
The Hyper-X research vehicle and its adapter will ride atop the
front of a specially configured Pegasus first stage solid rocket motor.
A
newly developed thermal protection system will protect the Pegasus composite
structures against severe heating loads associated with lower-altitude
hypersonic operations.
Other modifications to Pegasus include upgraded first
stage guidance and an avionics repackaging that permits ballasting of the
booster for flight conditions between Mach 7 and 10.

The Hyper-X missions will originate from Edwards AFB and will fly off the
coast of California.
The Hyper-X launch vehicle and scramjet research vehicle
“stack” will be air-launched from NASA’s B-52B carrier aircraft, the same one
used on the original Pegasus missions in the early 1990’s, as well as on the
X-15 and numerous other experimental aircraft programs in the past.
The
booster will accelerate the stack to a predetermined altitude and Mach number,
after which the X-43A will separate from the booster and fly under its own
power at seven times the speed of sound.
Currently, the world’s fastest air-
breathing aircraft, the SR-71 Blackbird, cruises slightly above Mach 3, or
approximately 2,100 miles per hour.
Hyper-X is planned to fly faster than any
air-breathing vehicle before, opening the frontier for aircraft with speeds
measured in miles per second.

Orbital is one of the world’s leading manufacturers of low-cost space
systems, including satellites, launch vehicles, space sensors and satellite
ground systems.
Orbital is also involved with satellite-based networks that
provide wireless data communications and high-resolution Earth imagery
services to customers around the world.

More information about Orbital can be found at http://www.orbital.com .

Media: Barron Beneski, 703-406-5528

email: beneski.barron@orbital.com

Investors: Timothy Perrott, 703-406-5997

email: perrott.tim@orbital.com