Define "useful". Generation ships could be a thing, we're arguably close to that level of tech right now, and that's with a relative pittance spent on space-re

Define "useful". Generation ships could be a thing, we're arguably close to that level of tech right now, and that's with a relative pittance spent on space-related tech for less than a century. Given enough R&D and raw resources it's probably an easier problem than curing cancer, and no one says that's impossible.