some interesting photos of solid booster sep....

Aviation Week & Space Technology

03/28/2005, page 58

Craig Covault

Cape Canaveral

Inmarsat's business propelled to new heights by extra Aerojet solid motors on Atlas V

Heaviest Satcom

The first EADS/Astrium Inmarsat 4, the largest commercial communications satellite ever launched, has completed four maneuvers to reach geosynchronous orbit where it has deployed its 30 X 40-ft. elliptical reflector and solar arrays spanning 148 ft.

Inmarsat 4 is being parked temporarily at a test location near the west coast of Africa before being drifted by late May toward its operational mobile communications station at 64 deg. E. Long. over the Indian Ocean.

The 13,183-lb. spacecraft was launched Mar. 11 from Cape Canaveral on the most powerful version to date of the Lockheed Martin International Launch Services (ILS) Atlas V.

The Inmarsat 4 spacecraft, with 630 channels and 228 spot beams, is the most complex civilian communications spacecraft ever built, says Michel LeMoine, EADS/Astrium Inmarsat 4 program director (AW&ST Mar. 7, p. 36).

The second Inmarsat 4 is to be parked later this year over the Atlantic region following launch on a Sea Launch Zenit. A third will later be placed over the Pacific region using a launcher yet to be selected.

The combined cost of the spacecraft and ILS mission was at least $250 million. And ILS and Inmarsat integrated Inmarsat 4 engineering details for five years before the flight, says Mike Jensen, ILS vice president for technical operations.

The Atlas V/431 vehicle--using three Aerojet solid motors (SRMs), a Russian Energomash/Pratt & Whitney RD-180 engine, and single-engine Pratt RL10 Centaur--put Inmarsat 4 into an initial 56,270 X 274-mi. "supersynchronous" transfer orbit.

The spacecraft's initial apogee, extending a quarter of the distance between the Earth and the Moon, was more than double the normal altitude used for satcom transfer orbits.

Inmarsat and Astrium calculated that by launching to a higher initial orbit, before maneuvering to about 22,300 mi., the spacecraft could conserve propellant to operate until at least 2020, says Andrew Sukawaty, Inmarsat CEO/chairman.

Inmarsat controllers commanded the satellite through four burns to raise perigee and lower apogee to the 22,300-mi. operational altitude at 0 deg. inclination.

http://www.aviationnow.com/media/images/awst_images/large/AW_03_28_2005_1306_L.jpg The most powerful Atlas V flown to date lifts off on 1.76 million lb. thrust with Inmarsat 4, the heaviest commercial satcom ever flown.Credit: LOCKHEED MARTIN

The spacecraft was assembled at Astrium facilities in the U.K., Germany, Spain and France, and about 150 European managers and engineers attended the launch. Their presence, along with the standard complement of Russian RD-180 engineers, exercised the Atlas Space Operations Center (ASOC) provisions for International Traffic in Arms (ITAR) regulations.

The Russians were positioned in an ASOC Mission Support Room with computer access to RD-180 system displays only, while the European managers and guests were restricted to a specific ASOC area where they could see just the U.S. system displays allowed with a special electronically programmed access card.

The Atlas V for the first time used three Aerojet SRMs instead of the twin solid motor configuration used earlier. Two of the 300,000-lb.-thrust SRMs were on one side of the vehicle and the third on the opposite side, a unique asymmetrical configuration.