-- Spacecraft Activation Underway With Commissioning Set in Late December --

-- Satellite to Provide Added Capacity and Expanded Service for South Asia and Indo-China --

DULLES, Va.Dec. 4, 2013-- Orbital Sciences Corporation (NYSE: ORB), one of the world s leading space technology companies, today announced that the SES-8, a communications satellite built by the company for SES S.A. of Luxembourg, was successfully launched into orbit yesterday aboard a Falcon 9 rocket operated by Space Exploration Technologies from Cape Canaveral, Florida. Lift-off took place at 5:41 p.m. (EST) on Tuesday, 3 December, and the satellite successfully separated from the rocket s final stage approximately 31 minutes into the mission, placing it into a super-synchronous transfer orbit.

Over the next several weeks, SES and Orbital engineers will conduct a comprehensive series of in-orbit tests to verify all spacecraft systems are functioning properly before it is officially turned over to SES for full operational control and commencement of commercial service. SES-8 is the sixth Orbital-built GEOStar satellite ordered by SES, a leading global satellite operator providing a broad range of communications services.

Early in the initial check-out and testing process, the SES-8 mission is proceeding smoothly, said Mr. Christopher Richmond, Orbital s Senior Vice President of Communications Satellite Programs. We are proud to continue to be a part of the SES team, helping increase communications capacity to meet the rapidly growing demand for telecommunications services in South Asia and Indo-China.

Orbital designed, built and tested SES-8 at its satellite manufacturing facility in Dulles, Virginia. The 3,200-kg satellite features 33 Ku-band transponders of 36 MHz capacity. In addition, SES-8 carries a Ka-band payload that together with the Ku-band payload consumes approximately five kilowatts of electrical power. Designed for an anticipated service life of 15 years, SES-8 will be co-located with NSS-6 at an orbit location of 95 East Longitude. Upon full activation, the satellite will provide expanded communications support for South Asia and Indo-China and additional capacity for Direct to Home (DTH), Very Small Aperture Terminal (VSAT), and government applications.

With this launch, 148 Orbital-built satellites have been completed and delivered to commercial, civil government and national security customers during the last 30 years. The SES-8 satellite is the 36th commercial geosynchronous communications spacecraft ordered by Orbital s customers around the world 31 have been launched to date and another five are now in design, production or pre-launch preparations.

About SES

SES is a world-leading satellite operator with a fleet of 54 geostationary satellites. The company provides satellite communications services to broadcasters, content and internet service providers, mobile and fixed network operators, and business and governmental organizations worldwide. SES stands for long-lasting business relationships, high-quality service and excellence in the broadcasting industry. The culturally diverse regional teams of SES are located around the globe and work closely with customers to meet their specific satellite bandwidth and service requirements. SES (NYSE Euronext Paris and Luxembourg Stock Exchange: SESG) holds participations in Ciel in Canada and QuetzSat in Mexico, as well as a strategic participation in satellite infrastructure start-up O3b Networks. Further information can be found at www.ses.com.

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.

Source: Orbital Sciences Corporation

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