-- Company to Perform Spacecraft and Airborne Systems Research, Analysis and Prototype Development --

DULLES, Va., Apr 29, 2010 (BUSINESS WIRE) --Orbital Sciences Corporation (NYSE:ORB) announced today that it has been awarded a contract by the U.S. Naval Research Laboratory (NRL) for a spacecraft and airborne system support services contract valued at approximately $95 million over a five-year period. The contract was won in a competitive process by Orbital's Technical Services Division (TSD), which is part of the company's Space Systems Group. The NRL contract calls for Orbital technical personnel to conduct prototype spacecraft and airborne system and subsystem research, analysis and development, as well as integration, testing, and data processing and documentation activities.

Orbital has previously supported numerous NRL aerospace programs, including Microwave Imager Sounder (MIS), Tactical Microsatellite Experiments (TacSat-1, TacSat-2, TacSat-4), Special Sensor Ultraviolet Limb Imager (SSULI), Upper Stage, Materials International Space Station Experiment (MISSE-5, MISSE-7), Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI), Spacecraft for the Universal Modification of Orbits (SUMO), Microelectronics and Photonics Test Bed (MPTB), WindSat, Interim Control Module (ICM), Low-Power Atmospheric Compensation Experiment (LACE), and Deep Space Program Science Experiment (DSPSE).

"This new contract marks the fourth time over the past 23 years that NRL has chosen Orbital as a supplier of technical support services," said Mr. John L. Pullen, Vice President of Orbital's Technical Services Division. "NRL has been a valued customer and we very much appreciate their continued confidence in our team. We are committed to strengthening our already highly successful relationship well into the future."

Orbital's TSD, based in Greenbelt, MD, provides space-related engineering, manufacturing and management support to U.S. Government agencies, typically supplying engineers, scientists, technicians and other professionals to work side-by-side with a customer's technical staff. Other major TSD customers include various NASA centers such as Goddard Space Flight Center, Ames Research Center and Johnson Space Center, as well as the U.S. Department of Energy and U.S. Air Force Research Laboratory. More information about Orbital TSD can be found at: http://www.orbital.com/SpaceTechnicalServices

About Orbital

Orbital develops and manufactures small- and medium-class rockets and space systems for commercial, military and civil government customers. The company's primary products are satellites and launch vehicles, including low-Earth orbit, geosynchronous-Earth orbit and planetary exploration spacecraft for communications, remote sensing, scientific and defense missions; human-rated space systems for Earth-orbit, lunar and other missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense systems that are used as interceptor and target vehicles. Orbital also provides satellite subsystems and space-related technical services to U.S. Government agencies and laboratories. More information about Orbital can be found at http://www.orbital.com.

SOURCE: Orbital Sciences Corporation

Orbital Sciences Corporation
Barron Beneski, 703-406-5528
Public and Investor Relations