Well, first there is Space Travel. But that would take so long as to take generations of people to get anywhere after finding if there is a Planet around Sun, that is suitable for life.
Well, with cutting down the length of time that it would take to journey to the stars, enters in time travel, and the thinking about that.
So, before any humans go anywhere, and it can take up to two years just to get to Mars, in an ellipitcal orbit to get there, then something else may have to happen first, and that is cutting down the length of the trip, thinking about Time Travel.
And anyway, all of are stuckies here in this inertial frame of reference (The Earth), and noone can get off of this Planet and actually live in Space without help, from supplies, that has to be continued. In deep space, one can think of ways of making the space ship supply the necessary food and such for such a long, long, long, long, long, long, long, long vovage, but then, it all costs money, and all takes -- time --- to build -- if it can be built!
Otherwise, you are stuck here on Planet Earth!
Good Luck!