One of things that always lingered in the back of my head with Bitcoin is its feasibility for use in interplanetary trade. While the idea of interplanetary trade is still a stuff of science fiction, I think it's a nice brain exercise to ponder on how Bitcoin will adopt to that kind of environment.
I found this fun bitcoin stackexchange thread that asked the same question that I've been mulling over if you are interested in picking apart this question [1].