DULLES, Va.Sept. 23, 2003--Orbital Sciences Corporation (NYSE:ORB) announced today that it has been awarded a sole-source contract for the Critical Measurements and Countermeasures (CMCM-1) Program under the Critical Measurements Program (CMP) contract by U.S. Army's Space and Missile Defense Command (USASMDC), located in Huntsville, AL. The contract, with an initial value of $14 million, includes launch vehicle design, payload interface development with two national laboratories, and vehicle integration and launch services. The CMP/CMCM-1 launches are scheduled to take place in 2005 and will test advanced reentry systems and countermeasures. Orbital has previously supported similar critical measurements and countermeasures flight tests under the CMP and predecessor programs with a total of nine launches carried out in 1993, 1996, 1997, 1999 and 2001. Orbital is also currently under contract for the CMP-4 program for two launches in 2004.

"Orbital is very pleased and excited to provide continued support for the Missile Defense Agency's Critical Measurements and Countermeasures Program, employing our cost-effective medium range target vehicle in another key application. We're also very much looking forward to the continuation of the long-standing working relationships and successful flight tests characteristic of this program over the last 10 years," 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 government and commercial 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.

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

    SOURCE: Orbital Sciences Corporation