-- THOR 5 to Begin Several Weeks of In-Orbit Testing Prior to Commencement of Commercial Service --
DULLES, Va., Feb 12, 2008 (BUSINESS WIRE) -- Orbital Sciences Corporation (NYSE:ORB), the world's leading manufacturer of smaller-sized geosynchronous (GEO) communications satellites, announced today that the THOR 5 satellite was successfully launched into orbit aboard an International Launch Services (ILS) Proton M/Breeze M launch system from the Baikonur Cosmodrome in Kazakhstan. The mission, which took place on February 11, began with the lift-off of the Proton rocket 6:34 a.m. (EST). The THOR 5 spacecraft was directly injected into geosynchronous (GEO) orbit approximately 9 hours and 23 minutes later. Over the next several days the satellite will execute a planned drift to its operational orbital location.

Mr. Christopher Richmond, Senior Vice President and head of Orbital's GEO satellite product division, said "We would like to thank ILS for an outstanding launch campaign for the THOR 5 satellite and we look forward to supporting our Telenor customer for many years to come."

Orbital designed, built and tested the THOR 5 satellite for Telenor Satellite Broadcasting of Norway at the company's satellite manufacturing facility in Dulles, Virginia. The spacecraft will occupy Telenor's 1 degree West Longitude orbital slot and will provide Ku-band fixed telecommunications and direct-to-home television broadcasting services. The THOR 5 satellite, which is based on Orbital's highly successful STAR(TM) platform, will have 24 transponders and will generate 3.6 kilowatts of payload power, or three times more payload power than the THOR II satellite it will replace. This additional capacity will improve Telenor's service coverage in the Nordic countries and Europe.

Orbital's commercial satellite business has experienced rapid growth over the past several years. In addition to THOR 5, the company currently has eight other commercial GEO satellites and five science and defense spacecraft in various stages of design, production and testing at its Dulles, Virginia satellite manufacturing facility. To accommodate this rapid rate of growth, Orbital has completed an expansion of its 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 Editors:

-- A high-resolution image of the THOR 5 satellite is available on Orbital's web site at: http://www.orbital.com/NewsInfo/ImagesMultimedia/Images/ SatelliteSpaceSystems/index.shtml (Due to its length, this URL may need to be copied/pasted into your Internet browser's address field. Remove the extra space if one exists.)

-- Additional THOR 5 mission information, including high-resolution images of the launch, will be available at the following Internet sites:



SOURCE: Orbital Sciences Corporation

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