How lines of code made a rocket explode.

Story of the most expensive software bug in the world.

On a fine June 4th, 1996, just 37 seconds after the celebrated launch, Ariane 5 rocket flipped 90 degrees in the wrong direction. Mission critical alarms started banging inside mission control; off the coast of French Guiana.

The rocket was making an abrupt course correction that was not needed, compensating for a…