Destruction of the First Ariane 5 Rocket in 1996

In 1996, the first Ariane 5 rocket was destroyed 40 seconds after takeoff due to a software failure. The underlying problem occurred in guidance software that had been reused from Ariane 4. During flight, the software attempted a conversion from a floating-point value to an integer, which instantly caused an overflow because the number being converted was too large.

This event is particularly surprising because the software had worked safely on Ariane 4, which never produced values of that magnitude. In computer systems, converting a floating-point number into an integer requires the number to stay within set limits. When the first Ariane 5 rocket produced numbers exceeding those limits, the guidance routine suffered an overflow error.

For ordinary readers, this illustrates how reusing established computer programs in new environments can have devastating results. Even though the guidance software was trusted, it was not prepared for the larger values produced during the new rocket's launch, leading to the destruction of the first Ariane 5 rocket just 40 seconds after takeoff.