Air Force Exercises First Option Under the 10-Year, $475 Million Orbital/Suborbital Program

New Order Represents the Fourth Minotaur Rocket Currently Under
Firm Contract

Orbital Sciences Corporation announced today that the
U.S. Air Force has exercised an option order for a Minotaur space
launch vehicle under the 10-year Orbital/Suborbital Program-2 (OSP-2)
contract that was awarded to the company earlier this year. The
Minotaur order is the first to be placed under the OSP-2 contract,
which is valued at up to $475 million over 10 years on an indefinite
delivery/indefinite quantity basis. The new order increases the launch
manifest for the Minotaur program to four missions to be carried out
over the next two years. This most recent Minotaur space launch
vehicle ordered by the Air Force is scheduled to launch a classified
payload in 2005. In addition, Orbital is currently under firm contract
to carry out three other Minotaur missions, including N-FIRE and
XSS-11, both of which are scheduled to be launched in 2004, and
COSMIC, scheduled for launch in 2005.

“We are very pleased to have the opportunity to conduct
cost-effective military space missions for the Department of Defense,”
said Mr. Ron Grabe, Orbital’s Executive Vice President and General
Manager of its Launch Systems Group. “The Minotaur program represents
an efficient use of government assets and commercial technology to
provide low-cost, operationally responsive and reliable launch
services for U.S. government customers.”

Orbital originally developed the four-stage Minotaur rocket under
the Air Force’s OSP-1 contract, which was awarded to the company in
1997. The Minotaur vehicle uses government-supplied Minuteman II
rocket motors that serve as the vehicle’s first and second stages. The
rocket’s third and fourth stages, as well as its guidance and control
system, use technology from Orbital’s highly reliable Pegasus XL
commercial rocket program.

Orbital has carried out two previous Minotaur missions, both of
which were fully successful. In January 2000, Minotaur made its
successful debut with the launch of the JAWSAT spacecraft. Later in
2000, the second Minotaur rocket successfully launched the
MightySat-II satellite into low-Earth orbit. Both missions were
conducted from launch facilities at Vandenberg Air Force Base (VAFB),
CA.

Over the past several years, Orbital has experienced rapid growth
in its launch vehicle programs for military space and missile
defense-related missions. The company’s launch vehicle business is
primarily centered at Orbital’s engineering and production facility in
Chandler, AZ, where the company employs approximately 800 people.
Orbital also maintains launch vehicle assembly, integration and test
facilities at VAFB, where the company employs nearly 100 people.

About Orbital

Orbital develops and manufactures small space systems for
commercial, civil government and military customers. The company’s
primary products are satellites and launch vehicles, including
low-orbit, geostationary and planetary spacecraft for communications,
remote sensing and scientific missions; ground- and air-launched
rockets that deliver satellites into orbit; and missile defense
boosters that are used as interceptor and target vehicles. Orbital
also offers space-related technical services to government agencies
and develops and builds satellite-based transportation management
systems for public transit agencies and private vehicle fleet
operators.

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

Note to Editors: High-resolution photos of the Minotaur space
launch vehicle are available on Orbital’s web site at:
http://www.orbital.com/NewsInfo/Images/SpaceLaunch/index.html