One of the biggest detriments to a manned mission to Mars is the fuel problem. If future Mars explorers ever want to return to Earth, they'll not only need enough fuel to get to Mars; they'll need enough to get back home too.
And fuel is heavy. If the plan is to pack it from Earth for the whole journey, then that adds a lot of weight to the spacecraft, which means even more fuel will be needed for liftoff from Earth. It's a bit of conundrum, one that can best be solved if there was some way of manufacturing fuel on Mars itself.
Now, in a brilliant new plan outlined in an article at IEEE Spectrum by NASA team lead Kurt Leucht, the dream of making fuel right on Mars itself appears to be a real possibility. And the only raw material needed to make the rocket fuel? Martian soil.
'In situ resource utilization'
The NASA team calls the method "in situ resource utilization," or ISRU, but you could also just call it a "dust-to-thrust factory." It involves extracting water from regolith, which is a specialized way of referring to Mars' distinctive red-hued dirt, and using a process called electrolysis to strip the soil of its trace amounts of water to separate it into its constituent hydrogen and oxygen. The hydrogen can then be combined with carbon, which is plentiful in Mars' atmosphere, to make methane, which can be used as rocket fuel.
Of course, all of this requires time and, well, an on-site factory that's up to the task. For that, NASA is developing a squadron of robots that can be set up on Mars years in advance of a return trip to Earth, which will tirelessly work to manufacture the rocket fuel.
The whole plan does have one small hitch. Namely, it depends on theories and projections about the water content of Martian soil. If we start digging and there's no water, or far less of it than anticipated, that could be a problem. But scientists are becoming increasingly confident that Mars' soil actually has a fair amount of water locked into it, which also bodes well for supplying the survival needs of astronauts who plan to stay a while on the Red Planet.
"This technology will one day allow humans to live and work on Mars," wrote Leucht, "and return to Earth to tell the story."