The Hindu : Ariane-5 lift-off postponed

Online edition of India's National Newspaper
Monday, Dec 02, 2002

National

National

Ariane-5 lift-off postponed

By R.K. Radhakrishnan

CHENNAI Dec. 1. The much-awaited lift-off of the 10-tonne Ariane-5 launch vehicle has been postponed by a few days, following a technical problem that occurred a few seconds before the inaugural flight at Kourou, French Guyana's spaceport.

The new date will be announced early next week, the Arianespace CEO, Jean-Yves Le Gall, said. The anomaly was not related to the Ariane-5 launcher itself and hence the optimism that an early launch was possible. The modified Ariane-5 was expected to launch two satellites, HOTBIRD-7 and Stentor, on November 28. India has been making use of the Ariane vehicle to launch its INSAT series of satellites.

The problem related to a communication gap between the onboard systems of the mega launch vehicle and the ground operations control centre. According to Arianespace, 6.8 seconds before the transmission by the on board system control to ignite the Vulcan-2 engine, the ground operations control system simultaneously ordered opening of the cryogenic arms and firing the extended, external igniters (AMF) of the launch table, whose function is to ignite the hydrogen which pre-chills the engine. The Vulcan-2 engine needs to be chilled down before it begins operations. The ignition activation status report failed to reach the ground operation control software, as a result of which the onboard control system did not trigger the ignition sequence as scheduled.

After the aborted take-off, the launch vehicle was transferred back to the assembly building, after draining the cryogenic upper stage. Arianespace personnel were working to ascertain why the AMF ignition was not acknowledged by the ground operations control system.

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