Forty years ago today — April 11, 1970 — the Apollo-13 mission launched from Cape Canaveral. Astronauts James A. Lovell, Jr., John L. “Jack” Swigert, Jr., and Fred W. Haise, Jr., were on their way to the Fra Mauro region of the moon.
(Apollo-13 launch. NASA image.)
Everything went well for the first two days, but on April 13th the Apollo-13 Service Module suffered a crippling explosion. The number two oxygen tank ruptured, causing a cascade of failures throughout the spacecraft’s systems — including the loss of all the oxygen from the number one tank as well.
(View of the damaged Service Module, taken by the Apollo-13 crew. NASA image.)
NASA aborted the Moon landing and turned their full attention to getting the astronauts home alive. The crew splashed down successfully on April 17th.
This page has a good explanation of the cause of the accident.
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