I’m sorry, but I don’t think multi-generation travel is possible, simply because I don’t think enough people would sign up.
I wouldn’t condemn my children and theirs to such a life without choice otherwise, and I would sign up in a minute for myself.
These plans are all based on the notion that multiple generations would be happy to exist in a very constrained environment so some future generation would reach some predetermined goal. I don’t buy it, people just don’t work that way. I will sacrifice for myself and my children and grandchildren. My descendants to the 5th generation are on their own.
Maybe I’m wrong, but I don’t think so.
“These plans are all based on the notion that multiple generations would be happy to exist in a very constrained environment so some future generation would reach some predetermined goal.”
No, the they would not necessarily be living in “a very constrained environment” at all. You are repeating all of the common misconceptions about such habitats. Nothing could be further from the truth. Also, you fail to understand how they would not necessarily eveen be all that interested in making the trip to find a planet, habitable or not. Until such time as propulsions come into existence which can providee the thrust needed to escape a planetary gravitational field witout exorbitant costs, human habitation of planets will be limited to special purposes. The principal habitats of humans would be off-planets. Consequently, human interest in habitable exo-planets will be limited for spacefaring humans. The inhabitants of the interstellar habitat will be more interested in living aboard their habitat than leaving it to become planetbound.