For Immediate Release
For More Information Contact:
Barron Beneski (703) 406-5528
Public and Investor Relations


-- Satellite Is First of Two Satellites Built by Orbital for SES
Scheduled To Be Launched in 2011 -

-- Launch Is First Commercial ILS Proton Rocket to Carry Two Satellites --

(Dulles, VA 18 July 2011) -- Orbital Sciences Corporation (NYSE: ORB), one of the world's leading space technology companies, announced today that the SES-3 satellite, built by the company for SES, was successfully launched into orbit aboard an International Launch Services (ILS) Proton rocket from the Baikonur Cosmodrome in Kazakhstan. The mission began on Friday, July 15, with the lift-off of the Proton space launch vehicle at 7:16 p.m. (EDT). The satellite successfully separated from the Proton rocket's Breeze M upper stage approximately eight hours after liftoff.

Mr. Christopher Richmond, Orbital's Senior Vice President and head of its communications satellite business unit, said, "We are pleased with the progress of the mission so far. The ILS Proton accurately delivered the satellite into its intended orbit and the spacecraft is performing nominally since its separation from the launch vehicle. Over the next several weeks, we will work with the engineering team from SES to conduct in-orbit testing to verify the spacecraft's systems before it enters commercial service. As we conduct the in-orbit check out of SES-3, we are also making the final preparations for the launch of the SES-2 spacecraft later in the third quarter of this year."

Mr. Richmond added, "The SES-3 launch was the first commercial ILS Proton shared mission with two spacecraft deployed by the same rocket. We are excited by this new capability which will allow Orbital to provide greater launch vehicle options to our customers, allowing them to more effectively manage launch."

Orbital designed, built and tested the SES-3 spacecraft at the company's satellite manufacturing facility in Dulles, VA. The state-of-art satellite will replace SES's existing AMC-1 spacecraft at the 103 degrees West longitude orbital position. The satellite carries 24 C-band transponders as well as 24 Ku-band transponders and has been designed to provide in-orbit services for 15 years. The SES-3 satellite is based on Orbital's GEOStar-2.4 platform and will generate approximately five kilowatts of payload power.

-- more --

Orbital-Built SES-3 Communications Satellite Successfully Launched
Page 2

SES-3 was the second of four commercial GEO communications satellites built by Orbital for SES scheduled to be launched in 2011, and the 24th GEOStar satellite to be orbited. An additional ten GEOStar-2 spacecraft are in various stages of design, production or testing with planned launches between 2011 and 2013.

About SES

SES (Euronext Paris and Luxembourg Stock Exchange: SESG) wholly owns the market-leading satellite operators SES ASTRA and SES WORLD SKIES, and participations in Ciel in Canada, QuetzSat in Mexico as well as in satellite infrastructure start-up O3b Networks. SES provides outstanding satellite communications solution via a global fleet of 44 satellites. For further information:

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

Note to Editors: High resolution images of the SES-3 satellite are available on Orbital's web site at:

# # #