Spacecraft Activation Underway as Part of In-Service Commissioning

Satellite to Expand HISPASAT s Services for South America

DULLES, Va.Mar. 24, 2014-- Orbital Sciences Corporation (NYSE: ORB), one of the world s leading space technology companies, today announced the Amazonas 4A commercial communications satellite, built by the company for HISPASAT S.A. of Spain, was successfully launched into orbit aboard an Ariane 5 ECA rocket on Saturday, March 22, 2014. Lift-off occurred at 6:04 p.m. EDT from the European spaceport at Kourou, French Guiana. The satellite was successfully deployed approximately 35 minutes into the mission, placing it into its targeted geosynchronous transfer orbit. HISPASAT and Orbital engineers have begun a comprehensive series of in-orbit tests to verify all spacecraft systems are functioning properly before it is officially turned over to HISPASAT for full operational control and commencement of commercial service.

The initial check-out and testing process indicates the Amazonas 4A mission is proceeding smoothly, said Mr. Christopher Richmond, Orbital s Senior Vice President of Communications Satellites. With the growing demand for expanded communications services in the South American region, we are proud to be a part of the HISPASAT team in its quest to meet this demand and we look forward to successful commissioning of the spacecraft in the coming weeks.

Amazonas 4A marks the 150th Orbital-built satellite to have been completed and delivered to commercial, civil government and national security customers over the past 32 years. Amazonas 4A is the 33rd satellite Orbital has produced based on its successful GEOStar commercial communications satellite platform, which supports all types of commercial communications payloads and is compatible with all major commercial launchers. Orbital-built satellites have now amassed about 1,100 years of in-orbit experience, a number that will continue to grow as the company is scheduled to deploy up to nine spacecraft in 2014 for commercial communications, space station logistics, scientific research and national security missions.

At launch, Amazonas 4A weighted approximately 3,000 kg. With its solar arrays extended, it measures 23 meters wide and nearly 5 meters tall, with two deployable reflectors and a Ku-band payload featuring 24 active transponders that will provide voice, wireless backhaul, internet and media application services to South America. Amazonas 4A will generate approximately 5.0 kilowatts of payload power and is designed for a 15-year mission life.

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. Follow the company on Twitter @OrbitalSciences.

Source: Orbital Sciences Corporation

Orbital Sciences Corporation
Barron Beneski, 703-406-5528
Public and Investor Relations
beneski.barron@orbital.com