In 1962, a single missing hyphen in a line of code caused NASA to deliberately blow up a rocket 293 seconds into flight — torching $18.5 million and years of work in one spectacular fireball. We dig into the Mariner 1 disaster, why a transcription error from a handwritten formula became one of the most expensive typos in history, and what it tells us about the terrifying gap between the instructions we write and the instructions machines actually follow.