Tim Furniss/PARIS

The successful third European Space Agency-funded demonstration flight of the Ariane 5 on 21 October has cleared the way for Arianespace to start commercial operations of the booster around next March, with two communications satellites.

Arianespace also revealed that it may order further Ariane 4 vehicles to extend the lifetime of the booster beyond 2002, so that a complementary Ariane 4-5 service continues to be available. The Ariane 5 will also fulfil a major new role as a low earth orbit launcher of constellations of mobile and multimedia communications satellites. Upgrades to the Ariane 5 to improve its geostationary transfer orbit (GTO) delivery performance are under way.

The Maqsat 3, built by Keyser Threde, was deployed by the 503 into its correct 1,027 x 35,863km geostationary transfer orbit at T+33m. The successful deployment of the Maqsat, a dummy payload representing the Eutelsat W2 communications satellite which was to have flown on 503, was the major success of the flight. It demonstrated the perfect placement in GTO, something not quite accomplished by the Ariane 502, launched in October 1997, 16 months after the dramatic loss of the first Ariane 5.

The flight success was vital to creating customer confidence and allowed the vehicle to to be handed over to Arianespace for commercial deployment. "We needed this definitive demonstration flight," says Alain Bensoussen, chairman of prime contractor French space agency CNES.

The 503's other first payload, the Aerospatiale-built Atmospheric Re-entry Demonstrator (ARD), was deployed 12min after launch in a unique deployment for a geostationary orbit launcher. The ARD splashed down in the Pacific about 1h 43min after launch and was later recovered, marking a double success for Aerospatiale, the Ariane 5's industrial architect.

Reaching a peak altitude of 830km, the ARD flew a global positioning system-assisted re-entry to demonstrate heatshield technologies for possible future European spacecraft.

Ariane 504's flight next March will be followed by up to three more Ariane 5s in 1999, six in 2000 and eight in 2001, with Arianespace services complemented by the Ariane 4. Up to 15 Ariane 4 and 5 launches a year are planned through to the end of 2001.

Source: Flight International