Ariane 5 Lofts Hosted Payload for U.S. Air Force

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PARIS — Europe’s Ariane 5 ECA heavy-lift rocket successfully placed two telecommunications satellites — one carrying the first commercially hosted payload for the U.S. Air Force — into geostationary transfer orbit Sept. 21. The satellites’ owners reported that both spacecraft were healthy in orbit.

The launch, from Europe’s Guiana Space Center spaceport in French Guiana, was the fifth and final mission for the Ariane 5 for 2011. The Arianespace commercial launch consortium of Evry, France, said the next Ariane 5 mission would be the early-2012 launch of Europe’s Automated Transfer Vehicle (ATV) supply ship to the international space station.

The Guiana Space Center, meanwhile, is preparing for the inaugural flight of a Europeanized version of Russia’s Soyuz vehicle, planned for Oct. 20.

The Sept. 21 flight, which was delayed for 24 hours due to a labor strike by personnel who manage the radar tracking of Ariane 5, carried the Arabsat 5C telecommunications satellite for the Arabsat consortium of Riyadh, Saudi Arabia, and the SES-2 satellite for Luxembourg-based SES.

Arabsat 5C, built by Europe’s Astrium Satellites and Thales Alenia Space, uses an Astrium-provided Eurostar 3000 platform. Weighing 4,630 kilograms at launch, it carries 26 C-band transponders and 10 transponders feeding Ka-band spot beams. The satellite is designed to provide 12 kilowatts of power to its payload at the end of its 15-year service life at Arabsat’s 20 degrees east orbital slot for coverage of the Middle East.

SES-2, built by Orbital Sciences Corp. of Dulles, Va., carries 24 C-band and 24 Ku-band transponders. The satellite weighed 3,200 kilograms at launch and is designed to provide six kilowatts of power to the payload at the end of its 15-year life in orbit.

SES-2 will be tested for between seven and 10 days at 77 degrees west before being drifted to its operating position at 87 degrees west.

In addition to its broadcast payload for North American customers, SES-2 carries the U.S. Air Force Commercially Hosted Infrared Payload (CHIRP), a staring, wide-field-of-view telescope designed to test infrared sensor technologies.

Air Force officials said they expect CHIRP to be activated within 30 days. It is designed to operate for nine and one-half months, during which time its Air Force controllers will select targets to validate CHIRP’s ability to detect missile launches. CHIRP managers have said they will coordinate with the U.S. Army’s White Sands Missile Range in New Mexico, among other intended demonstrations, to verify CHIRP’s performance.

CHIRP also is designed to determine whether U.S. government, and particularly U.S. military, use of commercial satellites to host small sensors can be made to work within the requirements of the military and of the owners of the commercial host satellites.

Air Force officials said Sept. 12 that they have learned many lessons from the CHIRP experience, notably that military sensor designs need to be completed well before a hosted payload arrangement is selected.

CHIRP is about a year late in being launched. Its initial $65 million budget has swollen to $82.5 million. CHIRP’s delays forced SES to scrap plans to place the payload on the SES-3 satellite because that spacecraft’s commercial mission required an on-time launch.

In the event, it was fairly straightforward for SES to reassign CHIRP to SES-2, which was next in line as part of a multisatellite order with Orbital Sciences.

 

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