Defence readies for the launch of its first communications satellite

In June this year the shared Optus and Defence C1 communications satellite will be launched from Centre Spatial Guyanais — the European space centre in French Guiana, heralding the start of a new era in satellite communications for the Department of Defence.

Joint Project 2008 Phase 3D was established in 1997 following an invitation from Optus for Defence to share Australia’s next generation commercial communications satellite. The project provides supply and support of a Defence-owned payload operating on the shared C1 communications satellite, together with Defence owned fixed terrestrial infrastructure for control and management of the Defence payload and the new communications network.

The network will provide Defence with satellite communications across Australia and throughout the Asia Pacific region in the X, Ka and UHF radio frequency bands. Contracts with Optus were signed in October 1999.

Defence and Optus are sharing the costs, benefits and risks of acquiring, launching and operating the C1 communications satellite.

The satellite delivers communications capability years ahead and at a fraction of the cost than could have otherwise been achieved, access to Optus’ experience in acquiring and operating communications satellites and an accelerated development of Defence’s satellite communications expertise.

Project Director Martin Weir said the lessons learnt in this program by Defence would assist greatly in the acquisition of future Defence satellite communications capabilities.

“With four separate payload sub-systems and 16 antennas, C1 is a very large and technically complex communications satellite. It will have a mass of about five tonnes at launch and with antennas and solar panels deployed, it will span 25m across and 8m in height,” he said

“The satellite will operate at 156 degrees east longitude from a geo-stationary orbit (a fixed position about 36,000km above the earth’s surface).”

The Defence payload will feature three payload sub-systems, crossbanding between the X and Ka-band payload sub-systems (that is, communications up in one band and down in another) and a combination of earth, fixed Australian/regional and steerable spot coverage beams.

He said that during launch, the satellite would be subjected to very high levels of vibration and stress and it will then be required to operate for more than 15 years in a harsh and forbidding environment — one characterised by high levels of radiation, extremes of hot and cold and an absence of atmosphere.

“As it will not be possible to undertake on-site repairs, the design, construction and testing of the satellite have been tasks of fundamental importance. The satellite design incorporates built-in redundancy where possible, and a comprehensive test program has demonstrated that the satellite meets and in many respects exceeds all functionality and performance design specifications.

“The test program, at satellite system level, has included thermal/vacuum, vibration, accoustics, passive intermodulation, compact antenna range and deployment mechanism testing.”

Construction of the satellite was completed in January 2003 and it is now at the launch site in French Guiana awaiting launch. Arianespace will launch the satellite using an Ariane 5-G launch vehicle.

“In recognising the inherent risks associated with satellite programs, Optus and Defence have implemented responsible risk management regimes, including the use of insurance to address the potential for the satellite to be lost or damaged during launch and the first five years of in-orbit operations.”

Mr Weir said fixed terrestrial infrastructure, including 11.2m diameter X-band and 9.0m diameter Ka-band anchor station antennas, together with primary and secondary Defence payload and operations control facilities, has been installed at Defence facilities in Canberra.

“Information Systems Division will be responsible for control and management of the new communications network. Optus has been contracted by Defence to supply payload operators, to maintain and support the fixed terrestrial infrastructure and to undertake telemetry, tracking and command of the satellite.

“A satellite management agreement has also been established to guide Defence and Optus in the management and operation of the shared satellite asset.

“The Australian Defence Satellite Communications Capability provides Defence with a substantial increase in communications capability.”