DULLES, Va.Dec. 3, 2003--

Award Adds Second Interceptor Program to Company's Fast-Growing Missile Defense Business

Orbital Sciences Corporation (NYSE:ORB) announced today that it has been awarded a contract by a Northrop Grumman Corporation (NYSE:NOC)-led team to conduct booster vehicle design, development, test, and early-production for the Kinetic Energy Interceptors (KEI) missile defense program. Raytheon Company (NYSE:RTN) will lead the team's interceptor-level system development, of which Orbital's booster vehicle is an integral part. Orbital's contract is valued at approximately $400 million from 2004 through 2010 and is projected to be staffed by approximately 300 Orbital employees during its peak activity period.

The U.S. Missile Defense Agency (MDA) today selected the Northrop Grumman-led team to be the prime contractor for the KEI program. The KEI program is intended to provide the United States with the ability to intercept and destroy hostile missiles during their boost and ascent phase, when the threat vehicle is most vulnerable. The KEI program is moving forward as a critical element of MDA's multi-layered defense system. It is planned as a complementary system to the other boost- midcourse- and terminal- defense interceptor programs currently under development. It will provide a land-based capability that can be quickly and easily adapted to sea-based platforms.

Commenting on the KEI booster vehicle contract selection, Mr. David W. Thompson, Orbital's Chairman and Chief Executive Officer, said, "Orbital is exceptionally proud to be a partner with Northrop Grumman and Raytheon on the KEI team. Together, we are advancing this national-priority program, which is at the forefront of the defense of our country."

"With the addition of the KEI boost vehicle program, Orbital's interceptor and target launch vehicles are now being used to help develop, test and deploy missile defense systems in each layer of MDA's architecture, including the boost, midcourse and terminal phases of the missile defense system," Mr. Thompson concluded.

The KEI program continues Orbital's rapid growth in the market for missile defense-related launch vehicle technology. Orbital is also the primary supplier of test and operational interceptor boosters for MDA's Ground-based Midcourse Defense (GMD) system, which is scheduled to begin initial deployments in 2004.

Mr. Ronald J. Grabe, Orbital's Executive Vice President and General Manager of its Launch Systems Group, stated, "The KEI contract award is further recognition of Orbital's demonstrated expertise in booster vehicle design, development and production. Our work on the GMD program, together with the introduction of numerous new target vehicle configurations over the past several years, gives Orbital an unmatched level of recent and relevant missile experience that we bring to the KEI team."

Mr. Grabe added, "Orbital's long and distinguished track record of successful launches in support of missile defense programs is emblematic of our company's total commitment to mission success. With major roles on both the KEI and GMD boost vehicle programs, two of the country's highest priority missile defense initiatives, we have rededicated ourselves to total customer satisfaction and product reliability."

About Orbital

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


    Note to Editors:

    --  A high-resolution photo of a full-size KEI boost vehicle is
        available on Orbital's web site at:
        http://www.orbital.com/NewsInfo/Images/MissileDefense/



    CONTACT: Orbital Sciences Corporation
             Barron Beneski, 703-406-5528
             Beneski.barron@orbital.com

    SOURCE: Orbital Sciences Corporation