Orbital-Built Telkom-2 Communications Satellite Successfully Launched Aboard Ariane Rocket; Mission Represents Company's Third Geosynchronous Satellite Deployment in 2005.

DULLES, Va. -- Orbital Sciences Corporation (NYSE:ORB) announced today that the Telkom-2 commercial communications satellite, built by the company for PT Telekomunikasi Indonesia Tbk (PT Telkom) (NYSE:TLK) was successfully launched into its targeted orbit aboard an Ariane 5 rocket on Wednesday, November 16. The mission originated from the spaceport at Kourou, French Guiana at approximately 6:46 p.m. (EST). The Telkom-2 satellite was deployed into a geosynchronous (GEO) transfer orbit about 34 minutes after lift-off. Initial communications with the satellite have been established and it is performing as expected in the early stages of the mission.

The Telkom-2 launch is the third Orbital-built commercial communications satellite to be deployed in 2005, following the successful launch and in-orbit check-out of the Galaxy 14 and 15 satellites for PanAmSat Corporation. During the next several days, Telkom-2 will perform a series of orbit-raising burns of its onboard rocket engine to achieve a circular orbit 22,300 miles above the Earth. For several weeks afterwards, the mission's engineering team will conduct comprehensive tests to ensure the spacecraft is ready for final hand-over to PT Telkom, which is scheduled to occur in December.

The Telkom-2 satellite will operate in the C-band frequencies from its orbital location at 118 or 108 degrees East longitude. The satellite is designed to provide fixed satellite services to a region including all of Indonesia, as well as areas of Southeast Asia and the Indian subcontinent. In addition to providing its state-of-the-art STAR spacecraft bus, Orbital also supplied the payload and is supplementing PT Telkom's existing ground segment with a new ground station and upgraded hardware and software.

Orbital is one of the leading suppliers of GEO communications satellites, which are based on the STAR family of smaller GEO satellite platforms and are capable of accommodating most types of commercial communications payloads. For many applications, the STAR design is an attractive alternative to the larger, more costly GEO satellites offered by other industry suppliers. The STAR satellites are smaller and are significantly less expensive to manufacture and launch. They are a perfect fit for customers in the early stages of building their business or for established companies that wish to replace or add capacity to their network.

Customer demand for Orbital's STAR GEO satellites has been robust in 2005. The company has received four firm and one optional order for its STAR-based GEO satellites thus far this year. In April, PanAmSat ordered its fourth spacecraft from Orbital, the PAS-11 satellite. This order was followed by an order for the Horizons-2 satellite by a joint venture between PanAmSat and JSAT of Japan. In September, Orbital received is third order of the year when Telenor ASA of Norway contracted with the company for the THOR II-R spacecraft. Orbital was recently selected for its fourth order of the year by MEASAT Satellite Systems (MSE:MEASAT) of Kuala Lumpur, Malaysia to build the MEASAT-1R spacecraft.

About Orbital

Orbital develops and manufactures small space and rocket systems for commercial, military and civil government customers. The company's primary products are satellites and launch vehicles, including low-orbit, geosynchronous 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. More information about Orbital can be found at http://www.orbital.com