Realistically, in-situ resource utilization seems like the only way of sustaining human presence outside of low Earth orbit. This is certainly the case for Mars, and it’s likely also the case for the Moon—even though the Moon is not all that far away (in the context of the solar system). It’s stupendously inefficient to send stuff there, especially when that stuff is, with a little bit of effort, available on the Moon already.
A mix of dust, rocks, and significant concentrations of water ice can be found inside permanently shaded lunar craters at the Moon’s south pole. If that water ice can be extracted, it can be turned into breathable oxygen, rocket fuel, or water for thirsty astronauts. The extraction and purification of this dirty lunar ice is not an easy problem, and NASA is interested in creative solutions that can scale. The agency has launched a competition to solve this lunar ice mining challenge, and one of competitors thinks they can do it with a big robot, some powerful vacuums, and a rocket engine used like a drilling system. (It’s what they call, brace yourself, their Resource Ore Concentrator using Kinetic Energy Targeted Mining—ROCKET M.)