Fourth Ariane 5 launch of 2006
On 13 October 2006, an Ariane 5 ECA launcher lifted off from Europe’s Spaceport in French Guiana on its mission to place two satellites into geostationary transfer orbits and deploy a demonstration antenna. Lift-off of flight V173 took place at 21:56 GMT/UTC (17:56 local time, 22:56 CEST/Paris). The satellites were accurately injected into the correct transfer orbits about 30 minutes later.
The payload satellites were DIRECTV 9S, which will supply television broadcast services to the contiguous United States of America, Alaska and Hawaii, and Optus D1, which will provide fixed communications and satellite broadcast services over Australia and New Zealand.
The mission also carried an additional passenger, mounted on the Ariane Structure for Auxiliary Payloads (ASAP) platform at the base of the payload stack. The Japanese Space Agency’s LDREX-2, a 1/25th scale version of an antenna that will be used on the ETS-8 engineering test satellite, was flown to validate the deployment process of the lightweight reflector.
The Ariane 5’s cryogenic, liquid fuelled, main engine was ignited first. Seven seconds later, the solid fuel rocket boosters were also fired, and a fraction of a second after that, the launch vehicle lifted off.
The solid boosters were jettisoned 2min:20sec after main engine ignition, and the fairing protecting the payload during the climb through the Earth’s atmosphere was discarded at 3min:14sec. The launcher’s main engine was shut down at 8min:56sec and the main cryogenic stage separated from the upper stage and its payload just over nine minutes into the flight.
Four seconds after main stage separation, the engine of the launcher’s cryogenic upper stage was ignited to continue the journey. The upper stage engine was shut down at 24min:44sec into the flight, at which point the launch vehicle was travelling at over 9300 metres per second (nearly 33 500 km/h) at an altitude of 685 kilometres and the conditions for geostationary transfer orbit injection had been achieved.
At 26min:58 sec, DIRECTV 9S separated from the launcher, followed Optus D1 at 32min:02sec.
After the LDREX-2 deployment test, the mission ended 1hr:37min:44sec after main engine ignition.
Ariane 5 ECA
Ariane 5 ECA is the latest version of the Ariane 5 launcher. It is designed to place payloads weighing up to 9.6 tonnes into geostationary transfer orbit. With its increased capacity Ariane 5 ECA can handle dual launches of very large satellites.