DULLES, Va.July 15, 2003--Orbital Sciences Corporation (NYSE:ORB) announced today that it has made the final in-orbit delivery of the BSAT-2c satellite to its customer, Broadcasting Satellite System Corporation (B-SAT) of Japan. Based on the company's STAR platform, BSAT-2c is the third in a series of three geostationary (GEO) communications satellites that Orbital built for B-SAT since 1999. The BSAT-2c satellite was launched into orbit aboard an Ariane 5 rocket on June 11, 2003. Following the launch, a team of Orbital engineers conducted a thorough evaluation of the satellite's operating systems and its onboard communications payload and determined that it is functioning as expected. Operational control of the satellite system was transferred to B-SAT on July 15.

"We are very pleased to deliver another high-quality satellite to B-SAT, which has been an anchor customer for our small GEO satellites," said Dr. Ali Atia, head of Orbital's GEO communications satellite business unit. "The completion of the BSAT-2c check-out process adds yet another milestone to our drive to be the leading supplier of small-sized GEO communications spacecraft to the global satellite market."

The BSAT-2c satellite will operate in Ku-band frequencies from its orbital location at 110 degrees East longitude. The spacecraft is optimized for a 10-year design life and will provide additional capacity for B-SAT's satellite broadcasting service throughout Japan. BSAT-2c is the third Orbital-built GEO communications satellite to be put in service by customers in the past 12 months.

Orbital develops and manufactures small space and missile 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

    CONTACT: Orbital Sciences Corporation
             Public and Investor Relations
             Barron Beneski, 703/406-5528

    SOURCE: Orbital Sciences Corporation