DULLES, Va., Oct 31, 2002 /PRNewswire-FirstCall via COMTEX/ --

SORCE Spacecraft to be Integrated with Pegasus Rocket at Kennedy Space Center in Preparation for December Launch

Orbital Sciences Corporation (NYSE: ORB) announced today that it has shipped the Solar Radiation and Climate Experiment (SORCE) satellite to the launch site at the National Aeronautics and Space Administration's (NASA) Kennedy Space Center (KSC), Cape Canaveral, Florida. In conjunction with a team from NASA and the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP), Orbital designed, manufactured, integrated and tested the spacecraft at the company's Dulles, Virginia facilities. In addition to supplying the satellite, Orbital is also the launch vehicle provider for the mission, using the company's unique air-launched Pegasus rocket. The SORCE mission is currently scheduled for a mid-December launch.

Unlike previous Pegasus missions that have flown from Cape Canaveral, the majority of the pre-launch activities during the final month before SORCE is launched are taking place at KSC. On typical Pegasus missions, the satellite is first shipped to Orbital's facility at Vandenberg Air Force Base, California for integration with the rocket. The combined system is then flown on a cross-country ferry flight to the Florida site. For the SORCE mission, Orbital will fly the Pegasus rocket to Florida in early November and will complete the integration of the satellite and conduct final testing prior to the launch at KSC's Multi-Purpose Processing Facility (MPPF).

About the SORCE Satellite

The SORCE mission is being led by a principal investigator from LASP with NASA's Goddard Space Flight Center providing project management and engineering oversight. Scientists and engineers at LASP designed, built, calibrated and tested the four science instruments on SORCE. The Mission Operations Center and the Science Operations Center are both located at LASP, which will operate the spacecraft over its five-year mission life and is responsible for the acquisition, management, processing and distribution of the science data.

SORCE is a key component of NASA's Earth Observing System (EOS) program. SORCE will address long-term climate change, natural variability and enhanced climate prediction, as well as atmospheric ozone and UV-B radiation. These measurements are critical to the study of the Sun and its effect on Earth and humankind.

About the Pegasus Rocket

Pegasus is the world's leading launch system for the deployment of small satellites into low-Earth orbit. Its patented air-launch approach, in which the rocket is launched from beneath an L-1011 carrier aircraft over the ocean, reduces cost and provides customers with unparalleled flexibility to operate from virtually anywhere on the planet. Pegasus has successfully completed 28 out of 31 missions since the early 1990's and has spawned several derivative vehicles, including Orbital's Taurus and the U.S. Government's Minotaur space launch vehicles.

About Orbital

Orbital is one of the world's leading developers and manufacturers of affordable space systems for commercial, civil government and military customers. The company's primary products include low-orbit, geosynchronous and planetary spacecraft for communications, scientific and remote sensing missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense boosters that are used as target and interceptor vehicles. 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.

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

    Notes to editors:
A SORCE mission Fact is available on Orbital's web site at: http://www.orbital.com/NewsInfo/Publications/index.html

High-resolution (300+ d.p.i.) photos of the Pegasus rocket are available on Orbital's web site at: http://www.orbital.com/NewsInfo/Images/SpaceLaunch/index.html

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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