[busterarm]

Part of Stephen Baxter's book Ring describes a large scale (as in population) interstellar trip and engineering the population making that trip for a long lifespan via eugenics.

If I recall correctly, the described humans were living spans greater than 400 years, among other traits, after a handful of generations.

If something as ambitious as Deep Space is your goal, you're probably better off engineering people to make the trip rather than waiting for technology that may never materialize.