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Enabling & Support

N° 20–1996: Flight 501 failure- first information

6 June 1996

The first Ariane-5 launch took place on Tuesday, 4 June 1996, from the Guiana Space Centre, Europe's Spaceport, at Kourou in French Guiana. The launcher was carrying the European Space Agencys four Cluster satellites, a science mission to study Earth-Sun interactions.

Following nominal ignition of the Vulcain engine (HO) at 09.33.59 hours Kourou time, i.e. 12.33.59 hours GMT or 14.33.59 hours Paris time, the flight proceeded as follows:


  • HO + 7.5 s :
    Ignition of solid booster stages and normal lift-off.
  • Up to HO = 37 s :
    Flight guidance and trajectory normal. At this moment the velocity of the launcher was Mach 0.7 (857 kph) and its altitude 3500 m.
  • HO + 37 s to HO + 39 s :
    Sudden swivelling of both solid booster nozzles up to the limit, recorded by telemetry.

    This caused the launcher to tilt sharply, given rise to intense aerodynamic loads on the launcher structure resulting in breakage.

    Following loss of launcher integrity, destruction of all launcher elements by the onboard neutralisation system.

    Preliminary analysis of the telemetry data confirms that the propulsion stages (solid boosters and cryogenic main stage) functioned correctly. The direction of inquiry is tending towards the launcher's "electrical and software system" An independent inquiry board is being sep up by ESA and CNES to determine the causes of the failure and propose corrective action. It will be asked to report by 15 July.

    ESA, the European Space Agency, has delegated management of its Ariane-5 programme to the French space agency, CNES.