Company Secures Required Authorization to Conduct Launch After Extensive Technical and Management Review

(Dulles, VA 31 August 2011) — Orbital Sciences Corporation (NYSE: ORB), one of the world’s leading space technology companies, today announced that it received a Commercial Space Transportation Launch License from the Federal Aviation Administration (FAA) to conduct the Commercial Orbital Transportation Services (COTS) program demonstration mission in early 2012. An expanded license covering the test flight of the company’s Taurus(R) II rocket in late 2011 is expected to be granted in the near future.

To secure the license, Orbital was required to submit extensive technical and program management data to the FAA about its Taurus II rocket and Cygnus(TM) spacecraft to ensure that all necessary operational requirements and safety precautions are met. Among the many items reviewed by the FAA were the rocket’s planned trajectory, ground tracking procedures, onboard safety and flight termination systems, and the experience and training of the launch operations team.

“We are very pleased to have been granted the Commercial Space Transportation Launch License by the FAA well in advance of our scheduled launch date in early 2012,” said Mr. Brent Collins, Orbital’s Senior Vice President and Taurus II Program Manager. “While we are very knowledgeable of the FAA licensing process because of our extensive experience with Pegasus and Taurus space launch vehicles, securing the FAA’s approval for a new rocket system is always challenging because of the rigor of their oversight. We feel this is a great vote of confidence in our launch vehicle design, the robustness of its subsystems, the thoroughness of our processes, and the training and operational experience of our launch team.”

For the COTS demonstration mission, Orbital will launch a Taurus II rocket carrying an operational Cygnus cargo logistics spacecraft that will autonomously rendezvous with and operate in close proximity to the International Space Station (ISS) until it is grappled with a robotic arm and berthed to the Station. For the earlier Taurus II test flight, an instrumented Cygnus simulator will be onboard to accurately characterize the launch environment

About Taurus II

Orbital is developing the Taurus II medium-class space launch vehicle to boost payloads into a variety of low Earth and geosynchronous transfer orbits and Earth escape trajectories. Taurus II incorporates proven technologies from the company’s Pegasus(R), Taurus and Minotaur rockets, and is supported by a “best-in-class” network of suppliers from the U.S. and around the world.

The Taurus II program currently has a backlog of 10 launches, beginning with a test launch slated for December 2011, followed by the COTS demonstration mission in early 2012. COTS is a joint research and development effort with NASA to develop a space transportation system capable of safely and reliably supplying the 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 the Taurus II rocket to U.S. civil government, military and commercial customers for dedicated launch services for medium-class satellites. From its launch site at Wallops Island, Virginia, Taurus II will be capable of supporting mid-inclination and polar orbiting spacecraft weighing approximately 13,500 lbs. and 5,500 lbs., respectively. In addition, Orbital plans to decide in early 2012 on the location of a West Coast launch site to optimize Taurus II’s performance to high-inclination orbits.

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