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Someone 10 hours ago

> I could argue that Apollo had a 1 in 20 chance of killing a crew.

NASA computed the chance of “landing a man on the Moon and returning him safely to Earth” as less than 1 in 20. I would think a lot more than 1 in 20 of those failures would result in killing crew members.

https://ntrs.nasa.gov/api/citations/20190002249/downloads/20...:

“Appreciating and deemphasizing risk in Apollo

Joseph Shea, the Apollo program manager, chaired the initial Apollo systems architecting team. The “calculation was made by its architecting team, assuming all elements from propulsion to rendezvous and life support were done as well or better than ever before, that 30 astronauts would be lost before 3 were returned safely to the Earth. Even to do that well, launch vehicle failure rates would have to be half those ever achieved and with untried propulsion systems.”

The high risk of the moon landing was understood by the astronauts. Apollo 11's Command Module pilot Mike Collins described it as a “fragile daisy chain of events.” Collins and Neil Armstrong, the first man to step on the moon, rated their chances of survival at 50-50.

The awareness of risk let to intense focus on reducing risk. “The only possible explanation for the astonishing success – no losses in space and on time – was that every participant at every level in every area far exceeded the norm of human capabilities.”

However, this appreciation of the risk was not considered appropriate for the public. During Apollo, NASA conducted a full Probabilistic Risk Assessment (PRA) to assess the likelihood of success in “landing a man on the Moon and returning him safely to Earth.” The PRA indicated the chance of success was “less than 5 percent.” The NASA Administrator felt that if the results were made public, “the numbers could do irreparable harm.” The PRA effort was cancelled and NASA stayed away from numerical risk assessment as a result.