Status Report

Arianespace/Starsem Flight ST12: The Fregat upper stage is ready to meet its AMOS 2 payload

By SpaceRef Editor
December 19, 2003
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Fueling of the Fregat upper stage for Arianespace/Starsem Flight ST12 has been completed at Baikonur Cosmodrome, and the Fregat is now ready to be mated with its AMOS 2 telecommunications satellite payload.

The N204 oxidizer was pumped into Fregat’s spherical tanks beginning on Saturday, December 13, and was followed by the loading of UDMH fuel – a process completed this evening.

Fregat is an autonomous upper stage that was flight qualified in 2000, providing a powerful and flexible propulsion system to extend the capability of the Soyuz launch vehicle’s three lower stages.

The Fregat for Flight ST12 is to be transferred tonight from the Cosmodrome’s MIK 40 fueling facility to the MIK 112 integration building. Once in the MIK 112, the upper stage will be moved into Starsem’s Upper Composite Integration Facility (UCIF) – a 587-square-meter high-bay clean room where the Fregat is to be mated with AMOS 2.

Flight ST12 will have a nominal mission duration of approximately 6 hours, 47 minutes – during which the re-ignitable Fregat stage will perform three separate burns while carrying the AMOS 2 payload.

The first Fregat burn will place the stage and its payload into a circular parking orbit. After a coast phase, Fregat will be ignited for a second burn at the ascending node for injection into an intermediate transfer orbit. Following another coast phase, the upper stage will be ignited a third time, enabling AMOS 2 to be released into a 42,166 km. X 10,785 km. geostationary transfer orbit, inclined 23.63 deg. Once its primary mission is completed, the Fregat will perform a final burn, placing the used upp
er stage into a safe orbit.

Flight ST12 is a joint Starsem/Arianespace mission that results from the two companies’ launcher family policy developed to best respond to the needs of their clients.

AMOS 2 originally was scheduled for launch on Ariane 5, but it was transferred to the Soyuz/Fregat to meet the customer’s requirements. This change was the result of a joint decision by Israel Aircraft Industries (the manufacturer of AMOS 2), Arianespace and Starsem – and was made in agreement with Spacecom Ltd., Israeli company that will operate AMOS 2.

SpaceRef staff editor.