Optus D3, the first of two telecommunications satellites has been installed atop the Ariane 5 launch vehicle in preparation for launch.

The satellite built by Orbital Sciences Corporation will be operated by Australian telecommunications provider, Optus.

The 2,500kg spacecraft bus is fitted with 32 Ku-band transponders for fixed communications and direct television broadcasting services to Australia and New Zealand.

Optus D3 has been integrated onto Ariane 5’s core stage that will lead to the final integration for the flight’s dual-passenger payload stack with Optus D3 as the lower payload and JCSAT-12, the other payload in the upper position.

The launch vehicle will carry about 7,655kg at lift-off with Optus D3 and JCSAT-12 weighing over 6,500kg and the remaining mass is represented by the payload installation / interface hardware and the SYLDA dispenser.

The integration will be followed by the final checkout before rollout to the launch complex.

Ariane 5 is scheduled for launch on 21 August 2009 during a one-hour launch window.