Posted: Tue, Jan 7, 2003, 10:23 AM ET (1523 GMT)
An inquiry board has concluded that the failure of a main engine cooling system led to the loss of an Ariane 5 launched last month, a finding that could permit the time-sensitive launch of an ESA science mission later this month. The inquiry board, led by Wolfgang Koschel of the German space agency DLR, concluded that a leak in a cooling circuit caused the booster's Vulcain 2 main engine to overheat and lose integrity, which in turn caused a thrust imbalance and eventual loss of control of the vehicle. The cooling failure was likely caused by fissures in cooling tubes as well as "non-exhaustive definition" of the loads the engine is subjected to during flight, according to an Arianespace press release. Because the cooling system is different on the Vulcain 1 engine used on the baseline Ariane 5, officials believe that no modifications are required to it, permitting it to return to flight as soon as a series of tests to the engine nozzle are concluded. This means that it is likely that the baseline Ariane 5 can return to service in time to launch ESA's Rosetta comet rendezvous mission, which must launch during a launch window that closes at the end of January. Arianespace plans to create a review board that will make a decision on the Rosetta launch date on January 14. The ESC-A variant of the Ariane 5 that uses the Vulcain 2 engine will likely return to flight in the second half of 2003.

Related Links:

•  BBC article
•  AFP article