DULLES, Va.Jan. 26, 2005--

    Launch of Telkom-2 Satellite is Planned for First Half of 2005
                         Aboard Ariane Rocket

Orbital Sciences Corporation (NYSE:ORB) today announced that it has completed the design, manufacturing and testing process for the Telkom-2 C-band satellite that the company is supplying to Indonesia's state-owned telecommunications company, PT Telkomunikasi Indonesia Tbk (PT Telkom). The Telkom-2 satellite is based on Orbital's STAR-2 satellite platform, generating approximately three kilowatts of electrical power and carrying 24 C-band transponders. In addition to the satellite platform, Orbital also designed, manufactured and tested the communications payload and is furnishing a complete ground station, including hardware and operations software. At the time of the launch of the Telkom-2 satellite, Orbital engineers will provide launch and mission support services to ensure a smooth transition to the customer's full operational control of the satellite.

Orbital completed the Telkom-2 production and testing process in just 18 months, from the full program start in May 2003, to its pre-launch ground delivery in November 2004. The launch of the satellite is currently in the scheduling process and is expected to take place in the first half of 2005 aboard an Ariane rocket originating from Kourou, French Guiana. The Telkom-2 satellite will enter a geosynchronous Earth orbit (GEO) 22,300 miles above the Earth, at 118 degrees East longitude. It will allow PT Telkom to expand its satellite communications coverage area from the Indonesian archipelago into the Southeast Asian region and the Indian subcontinent.

Over the past several years, Orbital has firmly established itself as a leading supplier of small GEO satellites designed to provide direct-to-home TV broadcasting, cable program distribution, business data network capacity, regional mobile communications and similar services. Orbital's GEO communications satellites are based on the company's STAR-1 and STAR-2 standard spacecraft platforms, which are able to accommodate most types of commercial communications payloads.

For many applications, the lighter weight, more affordable STAR design is an attractive alternative to the larger, more costly GEO satellites offered by other suppliers. Orbital's STAR satellites are smaller and significantly less expensive to manufacture and launch. They are an ideal fit for established companies that require incremental capacity for their network, like PT Telkom, or for customers in the early stages of building their business.

About Orbital

Orbital develops and manufactures small space systems for military, commercial and civil government customers. The company's primary products are launch vehicles and satellites, including missile defense boosters that are used as interceptor and target vehicles, ground- and air-launched rockets that deliver satellites into orbit, and low-orbit, geostationary and planetary spacecraft for communications, remote sensing and scientific missions. 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: www.orbital.com


    CONTACT: Orbital Sciences Corporation
             Barron Beneski, 703-406-5528
             beneski.barron@orbital.com

    SOURCE: Orbital Sciences Corporation