Contract Further Expands Company’s Role in Ballistic Missile Defense

(Dulles, VA 4 October 2001) – Orbital Sciences Corporation (NYSE: ORB)
announced today that it was recently awarded a $22 million development
contract
by the United States Army Space and Missile Defense Command (USASMDC) for
Phase
IIa of the Liquid Booster Target System. The objective of USASMDC’s program
is
to develop a liquid propellant booster system to support the Ballistic
Missile
Defense Organization (BMDO) Targets Program and to serve as a
threat-representative target to test various missile defense systems.
Orbital
was one of two companies selected from among the five who performed design
concept studies under Phase I contracts from USASMDC in early 2001.

Under the 18-month Phase IIa contract, Orbital will complete design and
development of its liquid propellant booster concept, integrate and test the
system, and perform a full-scale static firing of the booster engine.
Following
the static firing, USASMDC intends to select one of the two Phase IIa
contractors to perform the Phase IIb effort, which includes completion of
the
detailed liquid booster system design, development and a flight test in
early
2004. Following the successful completion of the Phase IIa-b development
program, USASMDC may choose to award additional production contracts.

Orbital’s liquid propellant booster concept is based on hydrogen peroxide
propulsion technologies originally developed by the company for the Upper
Stage
Flight Experiment (USFE) Program for NASA and the United States Air Force.
The
USFE Program was established as a technology demonstration program with a
goal
of developing a new low-cost, non-toxic liquid fuel upper stage for
suborbital
and space launch systems. The Liquid Booster Development Program will be
carried
out by Orbital’s Launch Systems Group at its engineering and manufacturing
facility in Chandler, Arizona.

Commenting on the award, Mr. Ronald J. Grabe, Executive Vice President and
General Manager of Orbital’s Launch Systems Group, said, “We are extremely
pleased to have been selected by USASMDC for the Phase IIa award. Orbital
looks
forward to developing new applications for our hydrogen peroxide propulsion
technologies and building on the successful relationship previously
established
with USASMDC on the STORM ballistic target and Consolidated Theater Target
Services programs.”

Mr. Michael J. Bender, Senior Manager of Business Development for Orbital’s
Launch Systems Group, added, “The Phase IIa contract award caps a four-year,
Orbital-led new business initiative to apply non-toxic and non-cryogenic
liquid
propulsion technologies to BMDO target systems. The benefits of a liquid
propulsion-based target vehicle includes a more accurate representation of
today’s potential hostile weapons systems and affordability and safety in
production, handling and flight test operations. With the possibility of
production contracts following Phase IIb, this initiative is consistent with
our
corporate strategy of aggressively pursuing missile defense-related programs
with the long-term potential for production-level contracts.”

Orbital develops and manufactures affordable space systems, including
satellites, launch vehicles, and advanced space systems. Orbital is also
involved with satellite-based networks that provide wireless data

communications
and high-resolution Earth imagery to customers all around the world.

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