Starsem/Arianespace Flight ST12

December 15 Update: The Fregat upper stage is fueled and ready for integration with AMOS 2

Flight ST12's Fregat upper stage has completed its fueling, and is now ready to be mated with the AMOS 2 telecommunications satellite payload.

Fregat's spherical tanks were filled with the N₂0₄ oxidizer beginning on Saturday, December 13, followed by the loading of UDMH fuel in a process completed this evening.

Fregat is an autonomous and upper stage that provides a powerful and flexible propulsion system to extend the capability of the Soyuz launch vehicle's three lower stages. It was flight qualified in 2000, and uses proven subsystems and components from previous spacecraft.

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.

Nominal mission duration of Flight ST12 will be approximately 6 hours, 47 minutes - during which the re-ignitable Fregat stage is to perform three separate burns while carrying the AMOS 2 payload.

Fregat's initial 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, a final burn will be performed by Fregat, placing the empty upper 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 the 1,370-kg. satellite 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.

Three burns will be performed by the Fregat upper stage during Flight ST12 in order to deploy AMOS 2 into geostationary transfer orbit.

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To read the December 28th update, "Success for Flight ST12 - The AMOS 2 satellite is in orbit!", click here.

To read the December 24th update, "The Soyuz/Fregat is in the launch zone!", click here.

To read the December 12th update, "Fueling of the AMOS 2 satellite is complete", click here.

To read the November 26th update, "Pre-launch checkout underway for the AMOS 2 satellite ", click here.

To read the November 18th update, "Preparations have begun for the liftoff of AMOS 2 ", click here.

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