-- Company Providing Both the Satellite and Launch Vehicle For Important Mission to Study How the Sun and Aerosols in the Atmosphere Affect Earth's Climate --

(Dulles, VA 22 February 2011) -- Orbital Sciences Corporation (NYSE: ORB) today announced that it is in final preparations to launch the company-built Glory satellite for the National Aeronautics and Space Administration (NASA). The Glory satellite will be launched into low-Earth orbit by Orbital's Taurus XL space launch vehicle. The Glory launch is currently scheduled to take place on Wednesday, February 23, 2011 from Vandenberg Air Force Base, CA (VAFB) at 2:09 a.m. (PST). This operational schedule is subject to the completion of final pre-launch activities, as well as acceptable weather conditions at VAFB at the time of the launch.

The powered flight sequence for the Glory mission will take approximately 13 minutes, from the time the Taurus XL rocket lifts off from the 576-E launch pad at VAFB to the time that the satellite is deployed into orbit. Orbital will launch the 1,164-pound Glory spacecraft into a circular polar orbit approximately 340 nautical miles above the Earth, inclined at 98.2 degrees to the equator. Over the next several weeks, following the initial in-orbit spacecraft check-out procedures, Glory will employ its onboard propulsion system to raise its orbit to 438 nautical miles, where it will join a constellation of other NASA Earth-observing satellites known as the "A-Train" that fly in formation and cross the Equator every afternoon. Glory will be the sixth satellite in the A-Train, joining five other NASA satellites: Aqua, Cloudsat, Calipso, Parasol and Aura.
The Taurus XL rocket will also carry three Cubesats that will be deployed by a Poly Picosatellite Orbital Deployer (P-POD) mechanism. The Cubesat and P-POD project was developed by California Polytechnic State University to enable the development and deployment of tiny satellites that measure four inches cubed and weigh less than 2.2 pounds. The three Cubesats to be launched aboard the Taurus XL rocket were developed by college students from Montana State University, the University of Colorado and a consortium of several Kentucky universities.

About the Taurus Launch Vehicle

Orbital developed the ground-launched Taurus XL vehicle to provide a reliable and cost-effective means of launching satellites weighing up to approximately 3,000 pounds into low-Earth orbit. The Glory mission will be the ninth flight of the Taurus rocket program.
The Taurus rocket incorporates advanced structural and avionics technology proven on the company's Pegasus rocket and other operational launch systems. It is also designed for easy transportability and austere site operations, offering customers rapid-response launches from a wide range of locations.
Orbital's Taurus rocket has also earned NASA's launch vehicle reliability certification, enabling the space agency to launch satellites of high value and importance aboard the launch vehicle. Taurus joins Orbital's other rocket that supports NASA missions, the air-launched Pegasus space launch vehicle, along with the Delta II and Atlas 5 rockets, as the only launchers to have earned that distinction.

About the Glory Satellite

Orbital's Space Systems Group designed, built and tested the Glory satellite at its Dulles, VA satellite production facility. It is based on the company's LeoStarTM small satellite bus that has served as the baseline platform for several previous successful NASA science spacecraft programs, including recent missions such as GALEX, SORCE and AIM. The Glory satellite features deployable solar arrays, three-axis stabilization, and X-band and S-band communications capabilities.
The Glory mission is being led by NASA's Goddard Space Flight Center under the direction of Project Manager Bryan Fafaul and Project Scientist Michael Mishchenko. The spacecraft carries two primary instruments, the Aerosol Polarimetry Sensor (APS), which will measure aerosols in the atmosphere, and the Total Irradiance Monitor (TIM), which will point toward the Sun and continue a 32-year data record of the Sun's brightness, or total solar irradiance.

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

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