Launch of Mariner 1

Mariner 1 was the first American attempt to send a spacecraft to Venus, launched from Cape Canaveral on an Atlas-Agena rocket. Shortly after liftoff the rocket veered off course, and a range safety officer destroyed it a few minutes into flight to prevent it from crashing in a populated area. Investigators traced the failure to a mistake in the guidance software, usually described as a missing bar or hyphen in a mathematical formula that had been transcribed into the computer code, combined with a failure of the radio guidance signal. The loss became a classic example of how a small error can destroy an expensive mission. Mariner 2 was launched weeks later and became the first successful planetary flyby, passing Venus in December 1962.

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