DULLES, Va., Apr 25, 2006 (BUSINESS WIRE) -- Teaming Arrangement with Alcatel Alenia Space Provides First Opportunity for Orbital to Introduce the Company's STAR-2(TM) Small Satellite Platform to SES GLOBAL

Orbital Sciences Corporation (NYSE:ORB) today announced that it has signed a contract with Alcatel Alenia Space of France to supply a STAR-2 spacecraft bus and provide final spacecraft and system integration and test of SES AMERICOM's AMC-21 commercial communications satellite. The spacecraft's engineering, manufacturing, integration and test activities will take place at Orbital's satellite manufacturing facility located in Dulles, VA. Alcatel Alenia Space will act as prime contractor for the project, provide the communications payload and deliver the AMC-21 satellite to SES AMERICOM, a leading U.S.-based satellite operator with headquarters in Princeton, NJ.

The AMC-21 satellite will carry 24 high-powered Ku-band channels and will operate from the 125 degree West longitude orbital location over the United States. The STAR-2 platform will deliver 6 kilowatts of gross power and support a 16-year on-orbit mission life. AMC-21 is scheduled to be delivered and launched in the spring of 2008.

AMC-21 is the sixth STAR-2 satellite purchased since April 2005 by customers around the world and the first spacecraft bus Orbital has sold to Alcatel Alenia Space and, by extension, to the SES GLOBAL family of companies.

Commenting on the contract announcement, Dr. Ali Atia, head of Orbital's communications satellite division, said, "We are pleased to be partnering with Alcatel Alenia Space on the AMC-21 program and to have this opportunity to introduce our STAR-2 satellite platform to a premier satellite operator, SES AMERICOM. We look forward to deepening our relationships with both companies in the coming months and years."

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

SOURCE: Orbital Sciences Corporation

Orbital Sciences Corporation
Public and Investor Relations:
Barron Beneski, 703-406-5528
Beneski.barron@orbital.com