-- Industry-Leading Small Launch Vehicles Selected to Deliver IRIS and OCO-2 Spacecraft to Orbit --

DULLES, Va., Jul 01, 2010 (BUSINESS WIRE) --

Orbital Sciences Corporation (NYSE:ORB), one of the world's leading space technology companies, today announced it has received two separate orders from NASA to launch scientific satellites on its industry-leading small rockets, Pegasus(R) XL and Taurus(R) XL. These contracts bring the total Pegasus and Taurus orders to 55 vehicles since the first Pegasus was purchased in 1988. Taken together, the two rockets have launched or will boost a total of 35 NASA scientific and technology demonstration spacecraft on 30 missions since 1990.

Orbital is scheduled to launch the Interface Region Imaging Spectrograph (IRIS) spacecraft in December 2012 aboard a Pegasus XL rocket from Vandenberg Air Force Base in California. IRIS is a NASA Small Explorer (SMEX) mission to measure the Sun's flow of energy through the dynamic region in the solar corona and heliosphere to help scientists better understand the effects of solar energy release processes on Earth. The planned 2012 launch will be the rocket's 45th mission since its initial flight in 1990 and the second Pegasus launch scheduled for that year, following the launch of the Orbital-built NuSTAR scientific satellite in February 2012.

In a separate contract, NASA tapped the company's Taurus XL launch vehicle to boost the Orbital-built OCO-2 environmental monitoring satellite into orbit. OCO-2 will provide critical space-based data on carbon dioxide in the Earth's atmosphere. A Taurus XL rocket, also launched from Vandenberg, will deliver the OCO-2 satellite into a 705 km sun-synchronous polar orbit where it will join NASA's "A Train" constellation of Earth monitoring scientific satellites. The launch, currently scheduled for early 2013, will represent the 10th flight of a Taurus rocket since its first launch in 1994. The next scheduled Taurus launch will boost the Orbital-built Glory satellite into low-Earth orbit for NASA in the fourth quarter of 2010.

"Pegasus and Taurus have been the workhorses of the small launch market for reliable missions to orbit for two decades. With these two new missions, plus those already on the manifest, we expect that will continue to be the case for years to come," said Mr. Ron Grabe, Orbital's Executive Vice President and General Manager of the Launch Systems Group. "With NASA's planned budget increases for small and mid-class science satellites, which deliver high value and are well suited to fast development cycles, Orbital is prepared to support NASA with both spacecraft and the rockets that launch them into orbit to help provide the global science community with important data about the world in which we live."

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.

Note to Editors: High-resolution images of Orbital's space launch vehicles can be found at http://www.orbital.com/NewsInfo/ImagesMultimedia/Images/SpaceLaunch/index.shtml.

SOURCE: Orbital Sciences Corporation

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