@Setanta,
Yet we see how there is never any problem to choose recruits for astronaut training from a boatload of volunteers.
Every space mission weve had in the first years could have been a one way ticket, and the astronauts knew it. Added to that ongoing space risk is the one of generational time.
There was a program on the SCience Channel several years ago about how thinking about some type of suspended animation for half the crew for years at a time would be almost a necessity, and ditto for mixed sex crews. When were travelling at ONLY 0.1 "c", the ships are gonna have to be large enough to basically contain all kinds of fulfillments of many kinds of needs. And then, after many centuries of learning how uch long duration flights actually work, the concept of the huge mother ship large enough to be an actual ecosystem (with enough shielding from the gamma radiation) ould be a whole industry probably carried out in near earth orbit.
In Sky and Telescope their concept of a mother ship was a lrge "cigar shaped" ship here, in cross section, it would be tens of hectares . (That's gonna consume lots of natural resources just to construct. (SO, chances are, were probably gonna have to be advanced enough to be mining Fe/Ti/Ni asteroids just for the metal .
Well also need to be mining Jupiter for H3 . I can see the solar system becoming a busy neighborhood.
Another thing that the Fermi Paradox bears some fact is that, if a sufficiently advanced civilization were to exist that is able to accomplish interstellar travel. IT would leave an immense energy "track" that we could easily detect with our present instrumentsAND, we don't see anything yet.
As far as the crew and it keeping from going bat-****, I always liked the "holodeck" concept that they used on Star Trek.