Fourth Ariane 5
Launch of 2006
(16 October 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.
Flight
timeline
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 2 min: 20 sec after main engine
ignition, and the fairing protecting the payload during the climb through the
Earth's atmosphere was discarded at 3 min: 14 sec. The launcher's main engine
was shut down at 8 min: 56 sec 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 24 min: 44 sec into the flight, at which point the launch vehicle
was travelling at over 9,300 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 32 min: 02 sec.
After the LDREX-2
deployment test, the mission ended 1 hr: 37 min: 44 sec 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.
(source:
ESA)