No casualties were reported other than perhaps the ego of a few software engineers: The 1996 inaugural flight of the Ariane 5 rocket was cut short due to a series of software design missteps. We’ll analyze these historical flaws to discuss resilience and product security; Touching on the nuance of testing, validation, legacy code, assumptions during design, and, for when things don't blow up, the unique challenge of proving that a negative event did not occur.