Orbital Successfully Launches Minotaur IV Rocket For U.S. Air Force

Third Successful Flight of Minotaur IV in 2010 Extends Perfect Launch Record of Minotaur Rocket Family to 19 Missions Since 2000

Orbital Sciences Corporation (NYSE:ORB), one of the world’s leading space technology companies, today announced that it successfully launched a Minotaur IV space launch vehicle in support of the U.S. Air Force’s Space Test Program-S26 (STP-S26) mission. In a launch that originated from the Kodiak Launch Complex in Alaska on Friday, November 19, 2010 at 8:25 p.m. (EST), the rocket carried four microsatellites and two CubeSats into low-Earth orbit approximately 405 miles (650 kilometers) above the Earth. The Minotaur IV was equipped with a hydrazine auxiliary propulsion system (HAPS) that acted as a fifth stage to reach a higher orbit, approximately 745 miles (1,200 kilometers) in altitude, demonstrating a new multi-orbit capability. The STP-S26 mission was the 19th overall mission for the Minotaur product line over the last 10 years, all of which have been successful.

“The third successful Minotaur IV flight in 2010, and the second in less than two months, builds on our well-established record of mission success for the Minotaur rocket family. We are proud to have supported the U.S. Air Force with the next generation of the Minotaur launch vehicle family for the STP-S26 satellite program,” said Mr. Ron Grabe, Orbital’s Executive Vice President and General Manager of its Launch Systems Group. “With three successful launches in its first year of operations, the Minotaur IV is proving to be a valuable new capability for the Air Force to meet its space launch needs.”

The STP-S26 mission demonstrated a new capability for Minotaur IV, called the Multiple Payload Platform (MPP), which addresses the needs of small satellite customers. Several key facts about this new capability are as follows:

* The addition of a restartable HAPS stage enables the deployment of spacecraft at multiple orbital altitudes, allowing unique mission tailoring and cost sharing among several small satellites requiring different orbits.

* The MPP enables the deployment of up to 12 small satellites, consisting of four ESPA-class satellites, four smaller secondary satellites and four P-POD carriers.

Orbital has six additional Minotaur IV missions scheduled on its launch manifest, the next of which is the TacSat-4 mission for the Air Force, which will also originate from Kodiak, Alaska.

Orbital conducted the Minotaur IV STP-S26 launch under the U.S. Air Force’s Orbital/Suborbital-2 contract, which is managed by the Space and Missile Systems Center (SMC), located at Los Angeles Air Force Base, CA. The Space Development and Test Wing, based at Kirtland Air Force Base in Albuquerque, NM, oversees Minotaur launches for SMC.

About Minotaur IV

The Minotaur IV is a four-stage space launch vehicle that uses flight-proven propulsion, avionics and other subsystems. It leverages the experience of the Air Force’s Peacekeeper ICBM program, along with the extensive flight heritage of Orbital’s Minotaur I, Pegasus(R) and Taurus(R) space launch vehicles to produce a highly reliable launcher for U.S. government space programs. The standard space launch configuration of Minotaur IV is made up of three decommissioned Peacekeeper solid fuel rocket motors that Orbital has upgraded and integrated with modern avionics and other subsystems, and a solid fuel commercially-supplied upper stage. The Minotaur IV rocket is capable of launching payloads up to 4,000 lbs. (or 1,800 kg.) to low-Earth orbit.

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.