Don't get my wrong, I love this movie, but the original mission makes no sense.

First you have Taylor smoking a cigar in a spacecraft cockpit? HUH? I doubt that would be acceptable, even in 1968 or 1972 when the movie was supposed to take place. Then by Taylor's own words- they are knowingly trapped in the future with no possible way of ever returning to Earth. Of course they were actually on Earth, but that was a mistake and not the actual intended mission.

So assuming everything goes their way, the mission was to arrive in the future, on an unknown planet with 3 men and one woman to do what? Repopulate with no way to every communicate with Earth? Total sketchy mission to say the least.