Ariane 5

The Ariane 5 is a launcher, usually used to put satellites in earth orbit. Now touted as highly reliable, its maiden flight was a disaster. It took 10 years and $7 billion to make.

It took 1 bug and 40 seconds to destroy. [1]

The internal SRI software exception was caused during execution of a data conversion from 64-bit floating point to 16-bit signed integer value. The floating point number which was converted had a value greater than what could be represented by a 16-bit signed integer. This resulted in an Operand Error. The data conversion instructions (in Ada code) were not protected from causing an Operand Error, although other conversions of comparable variables in the same place in the code were protected.