Orbital Selects “Antares” as Permanent Name for New Rocket Created by the Taurus II R&D Program

Company Brands Medium-Class Launch Vehicle in Preparation for First Flight in 2012

Orbital Sciences Corporation (NYSE: ORB), one of the world’s leading space technology companies, today announced that Antares(TM) will be the permanent operational name for the medium-class launch vehicle created by its research and development program formerly known as Taurus II. Orbital has been in the development phase of the new rocket program for the past four years. The operational phase of the program is scheduled to begin in 2012 with three flights on the manifest that will be conducted under the operational name of Antares.

“We are transitioning to the Antares identity primarily because a launch vehicle of this scale and significance deserves its own name, just like Orbital’s Pegasus, Taurus and Minotaur rocket programs that have come before it,” said Mr. David W. Thompson, Orbital’s President and Chief Executive Officer. “The successful introduction of the Antares launcher, with its contribution to our COTS and CRS programs along with future sales to other customers, is a linchpin of the company’s long-term growth and profitability strategy.”

Orbital selected the name in keeping with the company’s tradition of using Greek-derived celestial names for launch vehicles. Antares is one of the brightest stars in the sky. Classified as a “supergiant” star, it is located in the constellation Scorpius and has a red hue when observed by the naked eye.

About the Antares Launch Vehicle

Orbital is completing the development of the Antares medium-class space launch vehicle that will boost satellites and other payloads into a variety of low Earth and geosynchronous transfer orbits and Earth escape trajectories. Antares combines a powerful liquid-fuel first stage with proven avionics, propulsion and related technologies from the company’s other launch vehicle products and is supported by a “best-in-class” network of suppliers from the U.S. and around the world. The Antares program currently has a backlog of 10 launches, beginning in early 2012 with a test launch followed by a second demonstration mission later in the year, both conducted under the Commercial Orbital Transportation Services (COTS) agreement with NASA. COTS is a joint research and development effort to develop a space transportation system capable of safely and reliably supplying the International Space Station (ISS) with essential cargo. Orbital is also under contract with NASA for the Commercial Resupply Services (CRS) program with an eight-mission, $1.9 billion agreement to deliver cargo to the ISS from 2012 through 2015.

In addition to its work with NASA on the COTS and CRS programs, Orbital is also offering Antares to civil government, military and intelligence, and commercial customers for dedicated launch services for medium-class satellites.

From its launch site at Wallops Island, Virginia, Antares will be capable of supporting mid-inclination and polar orbiting spacecraft weighing up to approximately 13,500 lbs. and 5,500 lbs., respectively. In addition, Orbital intends to establish a West Coast launch site within the next three years to optimize Antares performance to high-inclination orbits, boosting its polar orbit capability to about 9,500 lbs.

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

Contact: Barron Beneski, (703) 406-5000, beneski.barron@orbital.com