Orbital Sciences
Corporation announced today that the BSAT-2c geosynchronous orbit
(GEO) communications satellite the company built for Broadcasting Satellite
System Corporation (B-SAT) of Japan was successfully launched aboard an Ariane
5 rocket on Wednesday, June 11, 2003. The mission originated from the
Arianespace launch complex in Kourou, French Guiana at approximately 6:38 p.m.
(EDT). The BSAT-2c satellite was deployed into a transfer orbit about 35
minutes later. Initial communications with the satellite have been
established and it is performing as expected in the early stages of the
mission. The BSAT-2c satellite is the third spacecraft Orbital has built for
B-SAT and the sixth GEO spacecraft Orbital has launched, each of them carried
aboard an Ariane rocket.

Over the next several days, BSAT-2c will perform a series of orbit raising
“burns” of its on-board rocket motor to achieve a circular orbit approximately
22,300 miles above the Earth. For several weeks afterward, a team of Orbital
and B-SAT engineers will conduct a comprehensive series of tests to ensure the
readiness of the spacecraft for final hand-over to B-SAT, which is currently
scheduled to occur in mid-August.

The BSAT-2c satellite will operate in Ku-band frequencies from its orbital
location at 110 degrees East longitude. The spacecraft is optimized for a 10-
year design life and will provide additional capacity for B-SAT’s satellite
network over Japan.

In the past several years, Orbital has firmly established itself as a
major supplier in the world market for GEO communications and broadcasting
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 industry’s larger, more costly GEO
satellites. The STAR satellites are smaller and significantly less expensive
to manufacture and launch. They are an ideal fit for customers in the early
stages of building their business or established companies like B-SAT that
wish to replace or add incremental capacity to their network.

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 a BSAT-2 series
satellite in orbit is available on Orbital’s web site at:
http://www.orbital.com/NewsInfo/Images/GEO/

* A Fact Sheet on the BSAT-2 series satellites is also available on
Orbital’s web site 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.