On Friday, January 30th, Arianespace initiated the payload “stack” build-up for its first Ariane 5 mission of 2009, which will orbit two large telecommunications satellites and a pair of auxiliary passengers on February 12 from the Spaceport in French Guiana.

The photo shows HOT BIRD-10 ready to be lowered onto the SYLDA payload dispenser, which is the cylindrical-shaped structure at the base of this integration rig in the Ariane 5’s final assembly building.

The process was initiated with the installation of Eutelsat’s HOT BIRD-10 spacecraft atop the Ariane 5 SYLDA dispenser system. As a result, the HOT BIRD-10/SLYDA combination is now ready to be positioned over the Ariane 5’s lower satellite — the SES NEW SKIES NSS-9 spacecraft — which will be installed directly atop the launcher’s core cryogenic stage. During the upcoming launch, HOT BIRD-10 will be released first in the payload deployment sequence, followed by the SYLDA dispenser’s separation, clearing the way for Ariane 5’s release of NSS-9.

HOT BIRD-10 was built by prime contractor EADS Astrium, and is based on the company’s Eurostar E3000 spacecraft bus. It will be the second HOT BIRD satellite launched for Eutelsat on consecutive Arianespace missions, and follows the identical HOT BIRD-9 spacecraft orbited by Ariane 5’s year-ending 2008 mission on December 20th of last year. HOT BIRD-9 had a liftoff weight of 4,880 kg. and will handle cable and satellite broadcasting duties at Eutelsat’s orbital slot of 13 degrees East — where HOT BIRD-10 also is to be located.

The NSS-9 satellite will have a liftoff mass of 2,230 kg. for the upcoming Ariane 5 mission, and was manufactured by Orbital Sciences Corporation. This satellite is to be positioned at 183 degrees East to provide communications links for SES NEW SKIES customers that include broadcasters, government users, Pacific island carriers and the maritime industry.

Joining NSS-9 and HOT BIRD-10 on Ariane 5’s February 12 launch are two 120-kg.-class Spirale microsatellites. They are demonstrators for a French space-based optical early warning program that will become part of an anti-ballistic missile defense system, and also contribute to other operational missions such as proliferation monitoring. The two Spirale spacecraft are installed on a ring-shaped support structure installed at the base of Ariane 5’s payload stack, and were built by Alcatel Space for Spirale program prime contractor EADS Astrium.

(Photo of HOT BIRD-10 about to be lowered onto the SYLDA payload dispenser courtesy of Arianespace)