Mariner 1, a NASA probe, crashed into the ocean not long after takeoff. The cause was a source of confusion for a long time, but seems to have been the result of a missing hypen.
One of the official reports, issued by the Mariner 1 Post-Flight Review Board, concluded that a dropped hyphen in coded computer instructions resulted in incorrect guidance signals being sent to the spacecraft. The review board specifically refers to a “hyphen,” although other sources also refer to an “overbar transcription error” and even to a misplaced decimal point.