29 November
2002
Arianespace issued the following press release this
afternoon regarding the delay in the launch of the Ariane 5 10-tonne
launcher.
The launch of flight 157 has been postponed by a few days following an
anomaly that occurred during the final phase of the launch preparation
sequence.
At 6.8 seconds before the transmission by the on-board system control
to ignite the Vulcain 2 engine, the ground operations control system
simultaneously gave the order to open the cryogenic arms and initiate the
external igniters (AMF) of the launch table, whose function is to ignite
the hydrogen which pre-chills the engine.
The igniter activation status report failed to reach the ground
operation control software and as a result the onboard control system did
not trigger the ignition sequence as scheduled at -3.0 seconds. Operations
then ceased and the launch vehicle, HOTBIRD 7 and STENTOR, and the launch
system went into safe mode.
Draining of the cryogenic upper stage via the launch vehicle purge
lines is currently in process. The operations will continue until Saturday
morning, when the launch vehicle will be transferred back to the Assembly
building. At that point it will be possible to ascertain why the AMF
ignition was not acknowledged by the ground operations control system.
Rectifying the anomaly and reconfiguring the flight are not expected to
take more than a few days. A new launch date will be announced early next
week.
