NASA just announced what the Mars 2020 rover will carry to the Martian surface, and one of them sounds like pure sci-fi: MOXIE, a machine that sucks in carbon dioxide from the Martian atmosphere and pumps out pure oxygen for use in rocket fuel—or someday, for humans to breathe.
"We’re not so much using the oxygen, but seeing can we generate it, what’s the production rate, what’s the efficiency. Those are the general kinds of things we’re looking at with this in-situ device. If you can make propellant for a craft’s ascent stage to get off Mars, that really changes the mission design. Or if you can cache and store oxygen before a crew arrives, and have a habitable environment when we get there."
Wait a second, why aren’t we doing that here?