Everyone Missed An Apollo 11 Mistake, And It Almost Killed The Astronauts Returning To Earth
“Fortunately for everyone, they did get lucky. During the technical debriefing in the aftermath of Apollo 11, the fly-by of the Service Module past the Command Module was noted by Buzz Aldrin, who also reported on the Service Module’s rotation, which was far in excess of the design parameters. Engineer Gary Johnson hand-drew schematics for rewiring the Apollo Service Module’s jettison controller, and the changes were made just after the next flight: Apollo 12.
Those first four crewed trips to the Moon — Apollo 8, 10, 11 and 12 — could have all ended in potential disaster. If the Service Module had collided with the Command Module, a re-entry disaster similar to Space Shuttle Columbia could have occurred just as the USA was taking the conclusive steps of the Space Race.”
The flight plan for Apollo 11 was straightforward, if not quite simple. Follow the same trajectory to the Moon that Apollo 8 and Apollo 10 undertook, then successfully enter lunar orbit, launch the Lunar Module, descend to the surface and land softly, perform the scheduled EVA, then ascend back to the Command and Service Module, return to Earth, jettison the Service Module, re-enter, and deploy the parachute to successfully splash down in the Pacific Ocean. Only uncovered well after the mission, there was a huge flaw: the Service Module wasn’t programmed to jettison properly! If things had gone differently, the Command Module could have been damaged, and would have burned up in the atmosphere, killing all on board.