No unobtanium? The whole thing is premised on wormholes! Yes GR supports wormholes---sort of. They are dramatically unstable. Nobody knows how to make one,

No unobtanium? The whole thing is premised on wormholes! Yes GR supports wormholes---sort of. They are dramatically unstable. Nobody knows how to make one, if such a thing is even possible. There are a bunch of planets, and they choose to visit the one with the absolute worst time dilation first?