Eutelsat W7 Telecommunication Satellite, France

Eutelsat W7 is a telecommunication satellite principally used for providing high-power direct-to-home (DTH) and digital broadcasting services to more than 450 channels from 36° East. The Eutelsat W7, which is part of the W-series, was launched into orbit on 24 November 2009 to replace the existing SESAT 1 satellite launched by Eutelsat on Proton rocket in early 2000.

Since Eutelsat W7's launch into orbit, the SESAT 1 has been continuing its commercial service at an alternative location. It is being operated by Eutelsat Communication of France.

W7 is co-positioned along with Eutelsat's W4 satellite, which currently aids pay-TV operators in Russia, Ukraine and sub-Saharan Africa. The new satellite has also doubled the bandwidth for digital broadcasting services in Russia, Ukraine and South Africa.

It will also replace the total capacity of SESAT 1 satellite, which assists Europe, North Africa, the Middle East and the central Asian regions, adding adds fresh capacity to South Africa via a high-powered fixed beam, and central Asia through a spot beam that can be changed in orbit.

The satellite is launched through the Spacebus-4000C4 platform on the piggyback of a Proton-M Briz-M vehicle. By 2011, four more satellites will be launched through the platform. The apogee motor of the W7 satellite is ignited three times over five days to rotate its orbit and solar panels. The antennas were installed in October 2009. The W7 satellite will enter into service for commericial applications in January 2010 after completion of its in-orbit tests.

W7 design

Alcatel Alenia Space was awarded a contract by Eutelsat Communications to manufacture and supply the Eutelsat W7 communication satellite in December 2006.

The W7 satellite is manufactured at Cannes Mandelieu Space Centre by Thales Alenia Space. It has been designed for a lifespan of 15 years. The satellite weighs around 5.6t (5,689kg) and consumes 12kW of power.

The satellite design also offers potential data and voice solutions, of specific use to the oil and gas sector in Russia, central Asia and west Africa.

Transponders

W7 is a digital channel transponded satellite that provides communication capacity, connectivity and flexibility. Around 70 Ku-band transponders installed in the satellite can be connected to five beams – for the European, Russian, African, Middle East and central Asian areas. The satellite also envisages highly efficient fixed and steerable beams principally suited for DTH applications.

Spacebus-4000C4

Manufactured by Thales Alenia Space, the satellite bus Spacebus-4000C4 is principally used for geostationary communication. It was derived from the 3000 series. An altitude and orbit control system with star trackers is installed in the Spacebus-4000C4.

The Spacebus-4000C4 is 5.5m tall. It consumes more than 16kW of power using its solar panels. The satellite bus has been used to launch the Canadian satellite Ciel 2, two Eutelsat spacecraft, W2A and W7 satellites on the Proton Briz M.

Launch vehicle

The W7 satellite was launched on the piggyback of International Launch Service's (ILS) Proton Briz M launch vehicle.

The name of the launch vehicle has been derived from the Proton rocket and Briz M booster stage manufactured by Khrunichev State Research and Production Space Centre, Russia. The launcher has successfully released the W7 satellite into geostationary transfer orbit after nine hours and 12 minutes from take-off from the Baikonur Cosmodrome.

W7 is the sixth satellite to be launched from the ILS Proton rocket. Another satellite, the DirecTV 12 commmunication satellite, was launched on the back of the Proton Briz M launch vehicle for DirecTV Inc. on 29 December 2009.

Ground station

The satellite launched into orbit can be controlled by five operational centres in Europe, Russia, Africa, the Middle East and central Asia, using ground equipment hardware and software. The W7 satellite operating in the Ku-band, can be controlled and tracked by a global satellite configuration and control element (GSCCE) using telemetry tracking and command links (TT&C) system.

The TT&C system is primarily used to track and control the satellite when it deviates from its orbit. Communication between the satellite and ground station takes place through the bandwidth allocated to service provider.