--Early Mission Results Indicate Satellite Is Operating as Expected --

DULLES, Va.Jun. 22, 2009-- Orbital Sciences Corporation (NYSE:ORB), the world’s leading manufacturer of smaller-sized geosynchronous (GEO) communications satellites, announced today that the MEASAT-3a satellite, which is based on the company’s STAR-2 platform, was successfully launched into orbit during a mission that took place on Sunday, June 21, 2009. Orbital designed, built, integrated and tested the MEASAT-3a spacecraft for MEASAT Satellite Systems of Kuala Lumpur, Malaysia. The satellite was delivered into its initial orbit by a Land Launch Zenit-3 rocket launched from the Baikonur Cosomodrome in Kazakhastan. Results from early tests of the satellite indicate that it is operating as planned for this phase of its mission.

“We are very pleased for our MEASAT customer that the satellite deployment was successful and that the early in-orbit tests are progressing well,” said Mr. Michael Larkin, Orbital’s Executive Vice President and General Manager of its Space Systems Group. “We look forward to completing the testing process and transferring operational control to MEASAT later this summer.”

The MEASAT-3a satellite is the fourth communications spacecraft in MEASAT’s in-orbit fleet. It will provide C-band communications services throughout Asia, the Middle East and Africa, and Ku-band direct-to-home television broadcasting to Malaysia and Indonesia. It is designed to generate approximately 3.6 kilowatts of payload power and carries 12 C-band and 12 Ku-band transponders. Over the next several weeks, the spacecraft will be maneuvered to its final orbital slot at 91.5 degrees East longitude over Southeast Asia.

Orbital is the world leader in the market for smaller, more affordable GEO communications satellites. Orbital’s highly successful communication satellites are based on the company’s STAR platform that provides up to 7.5 kilowatts of payload power. Orbital currently has nine additional GEO spacecraft in various stages of design, production and testing at its Dulles, VA satellite manufacturing facility for marquee customers such as SES Global, Intelsat and several regional satellite service operators around the world.

The company’s commercial communications satellite business is in addition to Orbital’s long-established presence in the market for civil government space- and Earth-science satellites and its rapidly growing position in the national security space systems market.

About Orbital

Orbital develops and manufactures small- and medium-class rockets and space systems for commercial, military and civil government customers. The company’s primary products are satellites and launch vehicles, including low-Earth orbit, geosynchronous-Earth orbit and planetary spacecraft for communications, remote sensing, scientific and defense missions; human-rated space systems for Earth-orbit, lunar and other 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 provides satellite subsystems and space-related technical services to government agencies and laboratories.

More information about Orbital can be found at http://www.orbital.com

Note to Editors: High-resolution images of the MEASAT-3a satellite in testing (photo) and in orbit (artist rendering) can be downloaded from Orbital’s web site at: http://www.orbital.com/NewsInfo/ImagesMultimedia/Images/SatelliteSpaceSystems/index.shtml

Source: Orbital Sciences Corporation

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