Company to Supply Next-Generation Data Transmission Instruments for Global Communications Network

Orbital Sciences Corporation announced today that ORBCOMM, Inc., has awarded the company a $17 million contract to supply six data communications payloads. The contract also includes options for two additional payload sets, which, if exercised, would bring the total contract value to $21.5 million. Orbital is scheduled to complete the delivery of the six initial payloads by mid-2007. The work will be carried out at Orbital’s satellite manufacturing facility in Dulles, Virginia.

In the 1990’s, Orbital designed, developed, built and deployed ORBCOMM’s global network of satellites, ground systems and data messaging distribution system based on the company’s proprietary smaller-sized space systems. The in-orbit satellites, while lasting well beyond their original five- to seven-year design life are due for a generational upgrade, for which the new communications payloads are designed.

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-orbit 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

Beneski.barron@orbital.com