Dulles, Va., Dec 4, 2001 /PRNewswire via COMTEX/ -- Orbital Sciences Corporation (NYSE: ORB) announced today that its Orbital/Suborbital Program Target Launch Vehicle (OSP TLV) successfully completed its mission as the target vehicle for yesterday's Ground-based Midcourse Defense (GMD) segment of the U.S. Department of Defense's missile defense program, which is being led by the Ballistic Missile Defense Organization (BMDO). The launch of the company's Minuteman-based OSP TLV marks the first time that Orbital has provided the primary target vehicle for the GMD segment. Orbital became the primary target vehicle supplier for the GMD segment under the OSP contract, which was awarded to the company by the U.S. Air Force in 1997. This mission was the second flight of the OSP TLV. Previously, Orbital conducted a successful TLV demonstration flight in May 2000.

At approximately 10:00 p.m. (Eastern time), the OSP TLV was launched from Vandenberg Air Force Base in California over the Pacific Ocean, where it was intercepted by an Exoatmospheric Kill Vehicle that was launched from the Ronald Reagan Test Site in the Marshall Islands.

"We are exceptionally proud to have played a key role in the success of the GMD test," said Mr. Ronald J. Grabe, Orbital's Executive Vice President and General Manager of its Launch Systems Group. "Our launch team is fully committed to maintaining the operational excellence, displayed in this test, for future GMD missions."

In addition to its new role as the primary target supplier for GMD, Orbital also supplies target launch vehicles for numerous other missile defense-related programs. These include the U.S. Navy's Theater Wide and Area Wide programs, the U.S. Army's THAAD, PAC-3, TCMP and SRALT programs, and a new liquid fuel propulsion system that may be used in the U.S. Air Force's Airborne Laser program.

Orbital develops and manufactures affordable space systems, including satellites, launch vehicles, electronics and advanced space systems. Orbital is also involved with satellite-based networks that provide wireless data communications and high-resolution Earth imagery to customers around the world. More information about Orbital can be found at http://www.orbital.com

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

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SOURCE Orbital Sciences Corporation

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

URL:              http://www.orbital.com
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