DULLES, Va., July 6 /PRNewswire/ -- Orbital Sciences Corporation (NYSE: ORB) announced today that it received about $725 million in new orders for its space and ground infrastructure systems during the first six months of 2000. As a result, Orbital expects its firm contract backlog at June 30, 2000 to be approximately $2.1 billion and its total contract backlog including options to reach $5.0 billion.

"All of Orbital's infrastructure systems groups reported strong new order bookings during the past six months," stated Mr. David W. Thompson, Chairman and Chief Executive Officer. "With continued robust contract wins in the second half of the year, 2000 has the potential to be Orbital's fifth straight year of $1 billion-plus annual new order bookings," he added.

Orbital's space and ground infrastructure systems consist of satellites and other space systems, launch vehicles, electronics and sensors, and ground systems. Its largest infrastructure product sector, satellites and related space systems, received approximately $220 million of new orders so far this year. In addition, launch vehicle new orders exceeded $265 million, while electronics, sensors and ground systems bookings totaled about $240 million in the first half of 2000.

Orbital is one of the largest space technology and satellite services companies in the world, with 1999 total enterprise revenues (including revenues from unconsolidated affiliates) of approximately $915 million. The company, headquartered in Dulles, Virginia, employs about 5,500 people at major facilities in the United States, Canada and several overseas locations.

Orbital is the world's leading manufacturer of low-cost space systems, including satellites and space robotics, launch vehicles, electronics and sensors, satellite ground systems and related digital infrastructure. Its Magellan subsidiary is a pioneer in satellite-based navigation and communications products for consumer and industrial markets. Through its ORBCOMM and ORBIMAGE affiliates and ORBNAV subsidiary, Orbital is also a major operator of satellite-based networks that provide data communications, high- resolution imagery and automotive information services to customers around the world.

To learn more about Orbital, as well as to access its recent press releases, please visit its web site at http://www.orbital.com. SOURCE Orbital Sciences Corporation

CONTACT: Barron Beneski of Orbital Sciences Corporation, 703-406-5000 or beneski.barron@orbital.com/