-- Flight Extends Perfect Launch Record of Minotaur Rockets to 16 Consecutive Missions --

DULLES, Va.May. 20, 2009-- Orbital Sciences Corporation (NYSE: ORB) announced today that its Minotaur I rocket successfully launched the Tactical Satellite-3 (TacSat-3) for the U.S. Air Force. The mission originated earlier today from the Mid-Atlantic Regional Spaceport (MARS) launch facility at NASA’s Wallops Flight Facility on Wallops Island, VA. At approximately 7:55 p.m. (Eastern), the rocket’s first stage ignited, beginning its flight into low-Earth orbit. Approximately 12 minutes later, the Minotaur I deployed the TacSat-3 spacecraft in its targeted orbit of approximately 285 miles (460 kilometers) above the Earth’s surface.

Today’s mission was the 16th mission for the Minotaur program since its inception in 2000, all of which have been fully successful. It was also the third Minotaur I launch from the MARS facility, following the TacSat-2 and NFIRE missions conducted from the Eastern Virginia launch site in 2006 and 2007, respectively. Including the TacSat-3 mission, which carried four other smaller payloads, Minotaur I rockets have put a total of 30 satellites into orbit.

“We are very pleased with the results of this evening’s flight of the Minotaur I rocket, and are proud to be able to support the Air Force’s important work in the area of Operationally Responsive Space (ORS) systems,” said Mr. Ron Grabe, Orbital’s Executive Vice President and General Manager of its Launch Systems Group. “Following this successful launch, our Minotaur launch team’s focus will shift to the Minotaur IV vehicle, which will considerably extend the performance of the Minotaur family.”

Orbital will conduct the first two Minotaur IV flights later this year when it launches TacSat-4, the next in the Air Force’s series of smaller-sized tactical satellites, from Kodiak, AK, and the Space Based Space Surveillance (SBSS) satellite from Vandenberg Air Force Base, CA.

The TacSat-3 spacecraft is designed to meet the growing need of U.S. forces for flexible, affordable and responsive satellite systems. The program is a joint effort of the Air Force Research Laboratory’s Space Vehicles Directorate, Army Space and Missile Defense Command, Air Force Space and Missile Systems Center’s (SMC) Space Development and Test Wing, the Department of Defense’s ORS office, and the Office of Naval Research.

The overall launch service and management for the Minotaur I vehicle was provided by the Air Force SMC’s Space Development and Test Wing at Kirtland Air Force Base, NM.

About Orbital’s Minotaur Product Line

Orbital’s Minotaur product line was developed under the U.S. Air Force’s Orbital/Suborbital Program (OSP). The initial five-year OSP contract was competitively awarded to Orbital in 1997 and the company also won the follow-on 10-year OSP-2 contract in 2003. The Minotaur I space launch vehicle design used in today’s TacSat-3 launch is the original member of Orbital’s Minotaur family of launch vehicles, which includes both space launch vehicle designs and long-range suborbital vehicles for missile defense and other specialized launch missions.

The Minotaur vehicles are the only proven launch vehicles currently capable of supporting the Department of Defense’s evolving ORS launch requirements and are also specifically designed to be capable of launching from all U.S. spaceports, including government and commercial launch sites in Alaska, California, Florida and Virginia. Due to the minimal amount of specialized infrastructure that is required to support Minotaur launches, they can also be operated from other U.S. launch sites.

The Minotaur I space launch configuration combines Orbital’s commercial launch vehicle technologies, including upper stage rocket motors, structures, avionics and other elements, with government-supplied lower-stage rocket motor stages to create responsive, reliable and low-cost launch systems for U.S. Government-sponsored spacecraft. It can place up to 1,300 lbs. into low- Earth orbit.

The Minotaur family of launch vehicles utilizes standardized avionics and subsystems, mature processes and experienced personnel to make them reliable and cost effective. In addition to the Minotaur I space booster, Orbital’s Minotaur product line also includes:

  • Minotaur II - A three-stage suborbital rocket used as a target vehicle for testing U.S. missile defense systems and related missions;
  • Minotaur III - A three-stage suborbital rocket, Minotaur III can deliver suborbital technology demonstration payloads of up to 6,500 lbs. or serve as a target vehicle for testing U.S. missile defense systems and similar missions;
  • Minotaur IV - A heavier-lift four-stage space launch vehicle using retired Peacekeeper rocket motors, capable of launching U.S. Government-sponsored satellites weighing up to 3,800 lbs. into low-altitude orbit. The first Minotaur IV missions are scheduled for later this year, carrying the TacSat-4 and SBSS satellites for the U.S. Air Force; and
  • Minotaur V - An enhanced-performance version of the Minotaur IV space launch vehicle that may be used to launch government satellites into higher-energy orbits for missions related to space exploration and other activities beyond 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 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 government agencies and laboratories.

More information about Orbital can be found at http://www.orbital.com

Note to Editors:

High-resolution photos of the Minotaur rocket are available on Orbital’s website at: http://www.orbital.com/NewsInfo/Images/SpaceLaunch

Photos/Multimedia Gallery Available: http://www.businesswire.com/cgi-bin/mmg.cgi?eid=5969605&lang=en

Source: Orbital Sciences Corporation

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