An incident occurred on 11 April 1994 during a test on revalidated Vulcain engine M6-R1, carried out on SEP's PF50 teststand at Vernon (France) - see ESA-CNES Joint Press Release No 11-94.
Investigation of the incident has established that friction between the impeller and the casing of the oxygen turbopump caused a fire inside the pump, which burst as a result of the consequent pressure build-up.
In view of the fact that the definition of flight-standard oxygen turbopumps minimises the risk of such an occurrence, tests were able to continue on DFVLR's teststand at Lampoldshausen (Germany) after the necessary checks. Testing on SEP's stand at Vernon will resume in August 1994 once the test unit has been repaired.
For tests on the cryogenic battleship stage in Guiana, it has been decided to use an engine fitted with a flight-standard oxygen turbopump. In view of the current stage reached in preparations for the battleship test campaign, the change of engine will not affect the starting date for the tests, which are scheduled to begin in mid-July 1994.
The date of the first Ariane-5 qualification flight (501), scheduled for October 1995, should not be affected. The Ariane-5 development programme is carried out under the direction of ESA, which has delegated prime-contractorship to CNES. The Vulcain engine is being developed under the direction of SEP in collaboration with a number of European firms.