DULLES, Va.Sept. 4, 2003--Orbital Sciences Corporation (NYSE:ORB) announced today that it has been awarded a task order issued under the Sounding Rockets Program Follow-on (SRP-2) contract by U.S. Air Force's Space and Missile Systems Center Detachment 12, located in Albuquerque, NM for a suborbital rocket that will test an advanced penetrator. The basic contract covers the design and procurement of long-lead hardware in support of the Air Force's Missile Technology Demonstration (MTD) -3B program, with an option for missile fabrication and test and a second option for launch services. The initial contract value is $3.1 million, while the options would increase the contract value to $7.5 million. The launch of the MTD-3B rocket is currently scheduled to take place in 2006. Orbital has previously supported the MTD program with three launches that were carried out in 1995, 1997 and 1998. The MTD program uses real-time Global Positioning System information to provide highly accurate guidance and velocity information for high-speed Earth penetration tests.

"As the country's leading supplier of suborbital rockets to the U.S. military, we are very pleased to support the Air Force's missile testing activities, including the MTD-3 program," said Mr. Ron Grabe, Orbital's Executive Vice President and General Manager of its Launch Systems Group.

Orbital's launch systems, including space launch vehicles, missile defense interceptors and target and other suborbital rockets, are primarily produced at the company's engineering and manufacturing facility in Chandler, Arizona, and its vehicle assembly and integration facilities at Vandenberg Air Force Base, California. The company's Pegasus, Taurus, Minotaur and Peacekeeper space launch vehicles are used by commercial and government customers to deliver small- and medium-class satellites into low-altitude orbits above the Earth. The U.S. Department of Defense employs the company's suborbital rockets in missile defense systems primarily as threat-simulating target vehicles and interceptor boosters for U.S. national defense systems.

In addition to its launch vehicle systems, Orbital's other primary products are satellites and related space systems, which are also used by commercial, civil government and military customers. These products include low-orbit, geostationary and planetary spacecraft for communications, remote sensing and scientific missions. In addition, Orbital 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.

    CONTACT: Orbital Sciences Corporation
             Barron Beneski, 703-406-5528

    SOURCE: Orbital Sciences Corporation