I don&#x27;t like double posting, but I read this again and ran accross this statement towards the end of the OP:<p>&gt;But the frantic pace of the “space race” ensured that you had to sacrifice thorough ground testing in favor of debugging the technology in space.  This means that you automatically increase the risk to human subjects on board spaceships.<p>By my memory, the US lost most astros to ground testing than to flight, the Apollo fire being top of the list.  Training and testing are safer than flight, but are not absolutely safe.  There is a balance point where the risks presented by ever more training outweigh any further reduction in risk during flight.