During a press conference today in Kourou, French Guiana, Arianespace CEO Jean-Yves Le Gall provided initial information on the failure of Flight 157. He also announced the establishment of an independent inquiry board.
Initial data analysis performed last night showed that the countdown, engine ignition and initial phase of flight were normal. A first anomaly occurred 96 seconds into the mission, involving the cooling circuit for the Vulcain 2 engine that powers the main cryogenic stage.
From T + 178 sec to T + 186 sec, the engine speed changed and a significant flight control perturbation occurred. At T + 187 sec, the Ariane 5's payload fairing was jettisoned as planned, but the launcher's attitude was not correct. The launcher subsequently demonstrated erratic behavior.
In compliance with range safety procedures, the launcher was destroyed at approximately 456 sec. into the mission. The Ariane 5 was at an altitude of about 69 kilometers and a distance of 800 kilometers off the coast of French Guiana.
Jean-Yves Le Gall announced that an independent inquiry board is being set up, with members to be named within a few days. The board will have two main objectives:
1. Ensure that the Flight 157 anomaly will not affect upcoming launches of the baseline version of Ariane 5.
2. Analyze, understand and correct the Flight 157 failure causes so that the 10-ton-payload Ariane 5 version can resume launches with high reliability.
The date for the next press conference will be announced shortly following the submittal of initial conclusions by the inquiry board.
The launch date for the next scheduled Arianespace mission, Flight 156, which will use an Ariane 4 to orbit the NSS-6 satellite, has been confirmed for the evening of Tuesday, December 17.