The modern world is vastly different to either of the periods Prop mentions both in terms of our capacity for the retention of existing knowledge and the speed of developing new solutions to old problems.  In addition to which this is comparing two completely different things the technology required here is to keep people alive for extended periods of time.  Equally the technology required for a colonization would need to be permanent and designed to be used many times, quite different from the disposable, one-time-only technology of the 1960s. As a result knowledge of those earlier missions may well be a disadvantage.  We still have the ability to launch and fly spaceships and that knowledge is vastly improved on those early attempts.  As far as the issue of spinoff technology is concerned, if you’re looking to develop products designed for Earth, developing materials and technologies for extra-terrestrial environments is a very odd way to go about it.