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


-- SES-2 Is the Company's Fifth GEOStar-Class Satellite to be Deployed for SES --

-- CHIRP Sensor Integration Displays Value of Hosted Payload Business Model
for U.S. Government Customers --

(Dulles, VA 21 September 2011) -- Orbital Sciences Corporation (NYSE: ORB), one of the world's leading space technology companies, announced today that it is in final preparations for the launch later today of the SES-2 commercial communications satellite for its customer SES of Luxembourg. In addition to 48 commercial C- and Ku-band transponders, the SES-2 satellite is carrying the Commercially Hosted Infrared Payload (CHIRP) sensor, an experimental technology demonstration payload for the U.S. Air Force for which Orbital provided a fully integrated design compatible with the SES-2 spacecraft platform. The satellite will be launched into geosynchronous Earth orbit from the spaceport at Kourou, French Guiana aboard an Ariane 5 rocket.

"We are looking forward to the upcoming launch and the completion of the in-orbit testing of the SES-2 spacecraft for our customer," said Mr. Christopher Richmond, Orbital's Senior Vice President and head of its communications satellite business unit. "SES-2 will join four other Orbital-built GEOStar 2 spacecraft in the SES fleet, including SES-1, SES-3, NSS-9 and AMC-21, all of which continue to operate with high reliability, enabling SES to provide communications services to its customers around the world."

Commenting on the imminent deployment of the CHIRP sensor, program manager Brent Armand said, "Orbital's critical role in establishing the contract framework, the engineering processes and procedures, and the standard hosted payload interface to be first used by CHIRP, is helping pave the way for a new business value proposition for our government and international customers. Taking advantage of the regularity and reliability of the commercial space industry to deploy new-generation technologies in a timely way and at an affordable total mission cost is becoming an attractive option for government space mission planners."

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Orbital Preparing For Launch of SES-2 Commercial Satellite Carrying CHIRP Hosted Payload Sensor- Page 2

About the SES-2 Satellite

The SES-2 satellite is based on Orbital's GEOStar 2.4 bus, the company's largest and most powerful communications satellite. It carries 24 active C-band and 24 Ku-band transponders of 36 MHz capacity. Six of the channels in each band can be cross-strapped to the opposite band, enabling new service capability.

The SES-2 satellite will generate approximately 5.0 kilowatts of payload power and will have two 2.3 meter deployable reflectors. Following its launch and in-orbit check-out, SES-2 will be positioned at 87 degrees west longitude to provide services to North America.

About the CHIRP Sensor

An innovative three-way industry partnership was responsible for developing, integrating and testing the CHIRP sensor for the Air Force. SES acted as the prime contractor for the hosted payload project; Science Applications International Corporation (NYSE: SAI) developed and built the CHIRP sensor; and Orbital was responsible for the overall system design, integration and testing processes, as well as the designer and integrator of the hosted payload interface that will be employed for future hosted payloads aboard Orbital's commercial satellites.

The CHIRP sensor features a fixed telescope that can view one quarter of the Earth from geosynchronous orbit. The infrared sensor, based on a 2,000 by 2,000 pixel staring array, will test the potential of its wide field-of-view capabilities for future overhead persistent infrared missions for the U.S. Air Force.

About SES

SES (Euronext Paris and Luxembourg Stock Exchange: SESG) wholly owns the market-leading satellite operators SES ASTRA and SES WORLD SKIES and participation in Ciel in Canada and QuetzSat in Mexico, as well as a strategic participation in satellite infrastructure start-up O3b Networks. SES provides outstanding satellite communications solutions via a global fleet of 46 satellites. For further information:

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Orbital Preparing For Launch of SES-2 Commercial Satellite Carrying CHIRP Hosted Payload Sensor- Page 3

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:

A high-resolution image of SES-2 with the CHIRP hosted payload is available at:

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