-- Mission Marks the Fifth Flight of Antares Rocket and Fourth Deployment of Cygnus Spacecraft --

DULLES, Va.Oct. 26, 2014-- Orbital Sciences Corporation (NYSE:ORB), one of the world s leading space technology companies, today announced that it is prepared to launch the company s AntaresTM rocket carrying a CygnusTM cargo logistics spacecraft destined for the International Space Station (ISS) under the Commercial Resupply Services (CRS) contract with NASA. Pending completion of final vehicle testing and acceptable local weather conditions, the launch of the Orb-3 mission will take place on Monday, October 27, with lift-off scheduled for 6:45 p.m. (EDT) from the Mid-Atlantic Regional Spaceport located at NASA s Wallops Flight Facility in eastern Virginia. The Antares medium-class rocket will boost the Cygnus spacecraft into a targeted orbit of approximately 125 x 185 miles (200 x 300 kilometers) above the Earth, inclined at 51.6 degrees to the equator. Following in-orbit activation and testing after launch, Cygnus is slated to rendezvous and berth with the ISS on November 2. Live coverage of the Antares launch and Cygnus berthing with the ISS will be available on NASA Television at http://www.nasa.gov/ntv.

Orbital s Antares rocket will be carrying a Cygnus spacecraft, the SS Deke Slayton, named for one of the original Mercury Seven astronauts, said Mr. David W. Thompson, Orbital s Chairman and Chief Executive Officer. In addition to his distinguished career as an astronaut, Deke was an early proponent of commercial space initiatives and helped establish the Commercial Space Launch Act in October of 1984. Fittingly, the SS Deke Slayton will be launching during the same month that this groundbreaking legislation was enacted thirty years ago.

Under its $1.9 billion CRS contract with NASA, Orbital will use Antares and Cygnus to deliver up to 44,000 pounds (20,000 kilograms) of cargo to the ISS over eight missions through 2016. For each mission, NASA will manifest a variety of essential items based on ISS program needs, including food, clothing, crew supplies, spare parts and equipment, and scientific experiments.

For Orbital s fourth mission to the space station, which includes the 2013 full demonstration mission, the Cygnus spacecraft is carrying 5,050 pounds (2,290 kilograms) of supplies to the Space Station, including science experiments to expand the research capability of the Expedition 41 crew members aboard the orbiting laboratory, along with crew provisions, spare parts and experiment hardware. This mission will also feature Orbital s first use of the upgraded Castor 30XL second stage motor, which enables greater lift capacity for this and future missions.

Orbital privately developed the Antares launch vehicle to provide low-cost, reliable access to space for medium-class payloads. It is the largest and most complex rocket the company has ever produced. Under the Commercial Orbital Transportation Services (COTS) joint research and development initiative with NASA, Orbital also developed and demonstrated the Cygnus spacecraft, which is an advanced maneuvering vehicle that meets the stringent human-rated safety requirements for ISS operations. Together, these products showcase Orbital s ability to apply rigorous engineering approaches and commercial business practices to significantly shorten development timelines and lower operational costs of sophisticated space systems as compared to traditional government-run programs.

About Antares

The Antares medium-class launch vehicle represents a major increase in the payload launch capability that Orbital can provide to NASA, the U.S. Air Force and commercial customers compared to its heritage small-class space launch vehicles such as Pegasus and Minotaur. The Antares rocket can launch spacecraft weighing up to 14,000 lbs. (6,400 kg.) into low-Earth orbit, as well as lighter-weight payloads into higher-energy orbits. Orbital s newest launcher has completed four successful missions and is currently on-ramped to both the NASA Launch Services-2 and the U.S. Air Force s Orbital/Suborbital Program-3 contracts, enabling the two largest U.S. government space launch customers to order Antares for right-size and right-price launch services for medium-class spacecraft. For more information on Antares, visit: http://www.orbital.com/LaunchSystems/SpaceLaunchVehicles/Antares/.

About Cygnus

Orbital developed the Cygnus cargo spacecraft under a joint research and development program with NASA. Cygnus consists of a common Service Module (SM) and a Pressurized Cargo Module (PCM). The SM incorporates avionics, power, propulsion and communications systems already successfully flown aboard dozens of Orbital s LEOStar and GEOStar satellites. The PCM, designed and built by Thales Alenia Space under a subcontract from Orbital, is based on the Multi-Purpose Logistics Module (MPLM) previously used with the Space Shuttle. With a full load of cargo and fuel, the standard-configuration Cygnus weighs about 5,200 kilograms at launch and generates 3.5 kilowatts of electrical power while in orbit. It is capable of extended duration missions of a year or longer in space. For more information on Cygnus, visit: http://www.orbital.com/AdvancedSystems/Publications/Cygnus_factsheet.pdf.

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. Follow the company on Twitter @OrbitalSciences.

Source: Orbital Sciences Corporation

Orbital Sciences Corporation
Barron Beneski, 703-406-5000
Public and Investor Relations
beneski.barron@orbital.com