The first of two telecommunications satellite payloads for Arianespace's next heavy-lift Ariane 5 mission has been installed atop its launcher as preparations move into their final phase for the August 21 flight.
Optus D3 was integrated on Ariane 5's core stage during activity performed inside the launcher Final Assembly Building at the Spaceport in French
Guiana. This marks the initial step of final integration for the flight's dual-passenger payload "stack," in which Optus D3 is riding as the lower payload and JCSAT-12 is in the upper position. Integration of Optus D3 on Ariane 5 clears the way for mating of the payload stack's upper component — JCSAT-12 — along with the SYLDA dual-payload dispenser system and the launch vehicle's ogive-shaped payload fairing. Once this work has been completed, final checkout of the Ariane 5 will be performed, followed by its rollout to the Spaceport's ELA-3 launch complex on August 20. The final countdown then will begin for liftoff the following day during a one-hour launch window that opens at 7:09 p.m. local time in French Guiana.
The Ariane 5's total lift performance for the upcoming launch is approximately 7,655 kg. — with Optus D3 and JCSAT-12 weighing in at more than 6,500 kg., while the remaining mass is represented by the payload installation/interface hardware and the SYLDA dispenser. Both satellites for this fourth Ariane 5 mission of 2009 were built by U.S. manufacturers, and are to be orbited for two of Arianespace's key Asia-Pacific customers. Optus D3 is a product of Dulles, Virginia-based Orbital Sciences Corporation and will be operated by Australia's Optus telecommunications
provider. Optus D3 is outfitted with 32 Ku-band transponders for fixed communications and
direct television broadcasting services to Australia and New Zealand. JCSAT-12 was produced in Newtown, Pennsylvania by Lockheed Martin Commercial Space Systems and will be operated by Japan's SKY Perfect JSAT Corporation, serving as the successor to JCSAT-R , which currently is in geostationary orbit as a backup relay platform. The high-power JCSAT-12 satellite carries 30 Ku-band transponders plus 12 C-band transponders.