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Public and Investor Relations


-- Successful Flight of Minotaur IV Extends Perfect Launch Record of
Minotaur Family to 23 Missions --

(Dulles, VA 27 September 2011) - Orbital Sciences Corporation (NYSE: ORB), one of the world's leading space technology companies, announced today that its Minotaur IV space launch vehicle was successfully launched for the U.S. Air Force, placing the U.S. Navy's Tactical Satellite-4 (TacSat-4) into a precise orbit of the Earth. The Operationally Responsive Space (ORS) Office is the launch sponsor of the TacSat-4 program, which is demonstrating the use of standard interfaces to shorten development timelines and delivering tactical capabilities to the foot soldier.

The mission originated from the Kodiak Launch Complex in Alaska on September 27, 2011. The rocket's first stage ignited at 11:49 a.m. (EDT), beginning its flight into low-Earth orbit. Approximately 28 minutes later, the Minotaur IV deployed the TacSat-4 satellite into its targeted highly elliptical orbit of approximately 7,415 miles (11,865 kilometers) by 115 miles (185 kilometers) above the Earth's surface. The TacSat-4 launch was the fifth Minotaur IV flight and the 23rd overall mission for the Minotaur product line over the last 11 years, all of which have been successful.

"The successful Minotaur IV flight continues our well-established record of mission success for the Minotaur rocket family. Orbital is proud to support the U.S. Air Force with the newest member of the Minotaur launch vehicle family for the operationally responsive TacSat program," said Mr. Ron Grabe, Orbital's Executive Vice President and General Manager of its Launch Systems Group. "With a perfect track record of 23 successful launches over the last 11 years, the Minotaur family has proven to be a valuable asset for the Department of Defense to meet its space launch needs."

The Minotaur family of launch vehicles is based on government-furnished Peacekeeper and Minuteman rocket motors that Orbital has upgraded and integrated with modern avionics and other subsystems to produce a cost-effective launcher based on flight-proven hardware. The Minotaur product line utilizes standardized avionics and subsystems, mature processes and experienced personnel to make them reliable and cost effective. Minotaur rockets are capable of launching from all major U.S. spaceports, including launch sites in Alaska, California, Florida and Virginia.

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Orbital Successfully Launches Minotaur IV Rocket for U.S. Air Force
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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 and Taurus space launch vehicles to produce a highly reliable launcher for U.S. government space programs.

The 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, combined with a commercially-supplied solid-fuel upper stage. For the TacSat-4 mission, Orbital flew an enhanced performance configuration of the Minotaur IV which utilizes a STAR 48 solid fuel motor with thrust vector control as the fourth stage, replacing the Orion 38 motor that had flown on the previous two Minotaur IV space launches. Minotaur IV 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

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Note to Editors: High-resolution images of the Minotaur IV rocket can be found at: