DULLES, Va., March 29 /PRNewswire/ -- Orbital Sciences Corporation (NYSE: ORB) announced today that its Pegasus XL rocket, the world's premier small space launch vehicle, has been selected by Spectrum Astro, Inc. to launch the Communication/Navigation Outage Forecasting System (C/NOFS) satellite that it is manufacturing for the U.S. Air Force Space Test Program. The C/NOFS Pegasus launch is scheduled to be conducted in 2003. The primary objective of the C/NOFS mission is to provide the U.S. military with advance notice of irregularities in the Earth's ionosphere and atmosphere that may interfere with space-based communication, navigation and surveillance systems.

"The selection of Pegasus as the launch vehicle for the C/NOFS mission reflects the rocket's unmatched combination of mobility and reliability," said Mr. Ron Grabe, Executive Vice President and General Manager of Orbital's Launch Systems Group. "We look forward to establishing a close relationship with Spectrum Astro and contributing to another successful mission for the Air Force."

The logistics of the C/NOFS mission highlight the unrivaled mobility of Orbital's patented Pegasus air-launch system. The Pegasus rocket will be assembled, integrated and tested at Orbital's facility at Vandenberg Air Force Base, California. It will then be ferried aboard Orbital's L-1011 carrier aircraft to a launch site near the equator that is compatible with the low inclination orbit targeted for the C/NOFS mission. Orbital has not yet selected the launch site for the mission.

Orbital has conducted Pegasus missions from six separate sites worldwide, the first time a space launch vehicle has provided such operational flexibility. The most recent Pegasus mission occurred on October 9, 2000, when it successfully launched the National Aeronautics and Space Administration's (NASA's) High Energy Transient Explorer-2 (HETE-2) satellite from the Kwajalein Missile Range in the central Pacific Ocean.

Orbital's three-stage Pegasus rocket sets the standard in the small launch market, deploying satellites weighing up to 1,000 pounds into low-Earth orbit. Pegasus is carried aloft by the company-owned "Stargazer" L-1011 aircraft to a point approximately 40,000 feet over open ocean, where it is released and then free-falls in a horizontal position for five seconds before igniting its first stage rocket motor. A typical Pegasus mission lasts just over 10 minutes, from the time the rocket is released from its carrier aircraft to the time it deploys its satellite payload into orbit. Since its debut in 1990, Pegasus has conducted 30 launches and placed over 70 satellites into orbit.

Orbital is one of the world's leading manufacturers of low-cost space systems, including satellites, launch vehicles, space sensors and satellite ground systems. Its Magellan subsidiary offers the industry's broadest line of GPS-enabled navigation and positioning products for consumer and industrial markets. Through its relationships with ORBCOMM, ORBIMAGE and ORBNAV, Orbital is also involved with satellite-based networks that provide data communications, high-resolution imagery and automotive information services to customers around the world.

More information about Orbital can be found at http://www.orbital.com .

Contact for Investors: Timothy Perrott of Orbital Sciences Corporation, 703-406-5997, or perrott.tim@orbital.com . SOURCE Orbital Sciences Corporation

CONTACT: Media: Barron Beneski, 703-406-5528, beneski.barron@orbital.com, or Investors: Timothy Perrott, 703-406-5997, perrott.tim@orbital.com, both of Orbital Sciences Corporation/