-- Orbital Also Names Amer Khouri Vice President of Business

                            Development --

DULLES, Va.Sept. 19, 2007--Orbital Sciences Corporation (NYSE:ORB) has promoted Mr. Christopher Richmond to the position of Senior Vice President and the new head of the company's commercial geosynchronous (GEO) satellite business unit. Mr. Richmond succeeds Dr. Ali Atia, who is leading a research and development program for the company prior to his transition into retirement. The company also announced that Mr. Amer Khouri has been named Vice President of Marketing and Business Development for the commercial GEO satellite business. The market for commercial GEO communications satellites is served by Orbital's single largest product area, with 2007 revenues expected to exceed $300 million.

"I am very excited about having Chris and Amer in critical leadership roles in the satellite group," said Mr. Carl Marchetto, Orbital's Executive Vice President and General Manager of its Space Systems Group. "Chris has proven himself to be a highly capable executive with an ideal background for his new position. Likewise for Amer, with his years of marketing and business development service with Intelsat. His knowledge of the industry and network of contacts around the world will prove to be extremely valuable in our efforts to expand our market presence."

Mr. Richmond is being promoted from his role as Vice President of GEO Satellite Programs, which he held for the past four years. In this role, he oversaw the technical, schedule and cost performance of all active GEO satellite programs. Prior to this senior oversight role, Mr. Richmond served as Program Manager for several communications satellite programs, highlighted by the three Galaxy satellites Orbital built for PanAmSat, prior to its acquisition by Intelsat. Mr. Richmond's background in the satellite industry also includes ten years of service with Lockheed Martin Astrospace from 1987 to 1996, where he was the Engineering Program Manager for the ChinaStar-1 and A2100 AX programs. Mr. Richmond holds Masters and Bachelors degrees in Mechanical Engineering from Rutgers University.

Mr. Khouri comes to Orbital from Decision Strategies International Inc., a management consulting company he joined in 2006 after serving in the commercial satellite industry since 1995. Mr. Khouri held several positions with Intelsat from 2000 to 2006, culminating as Senior Vice President of Strategy, Business Development and Global Marketing. Prior to his years at Intelsat, he worked for Mitsubishi Electric America, where he served as Director of Sales and Marketing to establish the company's distribution and marketing infrastructure in North and Central America. Mr. Khouri holds a Masters Degree in Business Management from the University of Maryland, as well as Masters and Bachelors degrees in Electrical Engineering from Catholic University.

Orbital's commercial satellite business has experienced rapid growth over the past several years. Including the five new orders the company has booked so far this year, the company currently has 10 commercial GEO spacecraft in various stages of design, production and testing at its Dulles, VA satellite manufacturing facility. Two other spacecraft, Intelsat-11 and Optus D2, are now in Kourou, French Guiana, the site of their upcoming launch aboard an Ariane rocket in early October. To accommodate this rapid rate of growth, earlier this year Orbital completed an expansion of its satellite manufacturing plant that, together with other facility improvements, has increased its manufacturing throughput capacity by over 30% as compared to one year ago.

About Orbital

Orbital develops and manufactures small rockets and space systems for commercial, military and civil government customers. The company's primary products are satellites and launch vehicles, including low-orbit, geosynchronous-orbit and planetary spacecraft for communications, remote sensing, scientific and defense missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense systems 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.

Note to Editor: High-resolution photos of Mr. Richmond and Mr. Khouri are available upon request. Please send an email to public.relations@orbital.com.


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

    SOURCE: Orbital Sciences Corporation