DULLES, Va., April 10 /PRNewswire-FirstCall/ -- Orbital Sciences Corporation (NYSE: ORB) announced today that the Galaxy XII geosynchronous orbit (GEO) communications satellite the company built for PanAmSat Corporation (Nasdaq: SPOT) was successfully launched aboard an Ariane 5 rocket on Wednesday, April 9, 2003. The mission originated from the Arianespace launch complex in Kourou, French Guiana at approximately 6:52 p.m. (EDT) and the Galaxy XII satellite was deployed into a transfer orbit about 39 minutes later. Initial communications with the satellite have been established and it is performing as expected in the early stages of the mission. The Galaxy XII satellite is the fifth GEO spacecraft Orbital has launched, each of them carried aboard an Ariane rocket.

Over the next several days, Galaxy XII will perform a series of orbit- raising "burns" of its on-board rocket engine to achieve a circular orbit approximately 22,300 miles above the Earth. For several weeks afterward, a team of Orbital and PanAmSat engineers will conduct a comprehensive series of tests to ensure the spacecraft's readiness for its final hand-over to PanAmSat, which is currently scheduled to occur in late June.

The Galaxy XII satellite will operate in C-band frequencies from its orbital location at 74 degrees West longitude. The spacecraft is optimized for a 15-year design life and will provide capacity for PanAmSat's satellite network over the continental United States, Alaska and Hawaii.

In the past several years, Orbital has firmly established itself as a primary supplier in the world market for GEO communications satellites. The company's GEO satellites are based on the STAR(TM) family of smaller GEO satellite platforms, which are able to accommodate 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 the industry's traditional 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 established companies that wish to replace or add capacity to their network.

About PanAmSat

PanAmSat Corporation is the premier provider of global video and data broadcasting services via satellite. Operating a global network of 21 in-orbit spacecraft with more than 800 transponders and seven technical facilities on the ground, the company reaches 98 percent of the world's populations with entertainment and information delivered through cable television systems, TV broadcast affiliates, direct-to-home TV operators, Internet service providers, and telecommunications companies. More information about PanAmSat can be found at http://www.panamsat.com

About Orbital

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

Note to editors:

A high-resolution (300+ d.p.i.) artist rendering of the Galaxy XII satellite in orbit is available on Orbital's web site at: http://www.orbital.com/NewsInfo/Images/GEO/

A Fact Sheet on the three GEO satellites Orbital is building for PanAmSat is also available at: http://www.orbital.com/NewsInfo/Publications/

CONTACT: Barron Beneski, Public and Investor Relations of Orbital Sciences Corporation, +1-703-406-5528 or Beneski.barron@orbital.com.

SOURCE  Orbital Sciences Corporation
    -0-                             04/10/2003
    /CONTACT:  Barron Beneski, Public and Investor Relations of Orbital
Sciences Corporation, +1-703-406-5528 or Beneski.barron@orbital.com/
    /Web site:  http://www.orbital.com http://www.panamsat.com/
    (ORB SPOT)

CO:  Orbital Sciences Corporation; PanAmSat Corporation
ST:  Virginia
IN:  ARO TLS
SU:


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