On 4 June 1996, an unmanned Ariane 5 rocket launched by the European Space Agency exploded just forty seconds after its lift-off from Kourou, French Guiana. The rocket was on its first voyage, after a decade of development.
A board of inquiry investigated the causes of the explosion. It turned out that the cause of the failure was a software error in the inertial reference system. Specifically, a 64-bit floating point number relating to the horizontal velocity of the rocket with respect to the platform was converted to a 16-bit signed integer. The number was larger than 32 767, the largest integer storeable in a 16-bit signed integer, and thus the conversion failed.
Here’s the Ariane 5 rocket’s ill-fated first launch…
Ariane 5 has since been launched successfully over 50 times, and its reliability has made the company a powerhouse in the increasingly competitive space industry.
American rocketeers are attempting to reclaim a share of the lucrative satellite launch market from foregin firms. To win, they’re rewriting the rules and, in the process, ushering in a new era of the space industry: private space launches. Read about the battle for orbit in PM’s April 2013 issue – on sale 25 March.