Ariane 5 was designed by the European Space Agency (ESA) as a replacement for the successful Ariane 4 launcher. The intention was to create a reliable, high capacity, launch vehicle for ESA that could be used to support their contribution to the International Space Station as well as a range of other commercial and scientific launches.
On June 4, 1996, the US$500 million space craft was launched for the first time:
"The countdown, which also comprises the filling of the core stage, went smoothly until H0-7 minutes when the launch was put on hold since the visibility criteria were not met at the opening of the launch window (08h35 local time). Visibility conditions improved as forecast and the launch was initiated at H0 = 09h 33mn 59s local time (=12h 33mn 59s UT). Ignition of the Vulcain engine and the two solid boosters was nominal, as was lift-off. The vehicle performed a nominal flight until approximately H0 + 37 seconds. Shortly after that time, it suddenly veered off its flight path, broke up, and exploded. A preliminary investigation of flight data showed: "
"nominal behaviour of the launcher up to H0 + 36 seconds; "
"failure of the back-up Inertial Reference System followed immediately by failure of the active Inertial Reference System; "
"swivelling into the extreme position of the nozzles of the two solid boosters and, slightly later, of the Vulcain engine, causing the launcher to veer abruptly; "
"self-destruction of the launcher correctly triggered by rupture of the links between the solid boosters and the core stage. "
"The origin of the failure was thus rapidly narrowed down to the flight control system and more particularly to the Inertial Reference Systems, which obviously ceased to function almost simultaneously at around H0 + 36.7 seconds.