[nrb]

How big of a lunatic would our great-great-great grandparents have considered us for telling them that soon the several-month trip across the USA will pretty soon take an afternoon, and going to the moon will take 3 days?

Sure, traveling at Voyager’s (impressive, but essentially wagon) speed won’t get it done. But betting against technological advancement has made fools of a vast many.

[calamari4065]

Generally it's taken for granted that the technological problems with generation ships can be solved with sufficient time and resources. We can probably build a metal box that lasts for a thousand years. We can probably design a sustainable closed ecosystem. We could probably build fusion reactors that run on interstellar hydrogen collected with ramscoops.

But the real problem with generation ships is not technological. Technology can't solve the fundamental social and psychological problems of locking some humans in a box for a hundred generations. That's the most important problem, and the one that's usually waved away with "oh you just can't imagine future technology"

[SoftTalker]

You'd probably need to create a religion for them about some gods/ancients that they are serving in their mission. That seems to be how humans stay focused on long-term social organization across generations.

[gomoboo]

See the Mormon generation ship in The Expanse: https://expanse.fandom.com/wiki/Nauvoo_(Books)

They were intending to use the ship to get to the Tau Ceti system: https://exoplanets.nasa.gov/exoplanet-catalog/7179/tau-ceti-...

Mormonism seems well-suited for the religion role you mention since they have the concept of a particular planet being close to the residence of their god: https://en.m.wikipedia.org/wiki/Kolob

[konart]

Or modify them genetically making them biological robots. Or create artificial humanoids similar to Abh: https://seikai.fandom.com/wiki/Abh

[int_19h]

https://en.wikipedia.org/wiki/Orphans_of_the_Sky