I had a dream that I was a twelve-year-old boy living on Mars with my dad. Our government sent us there to learn something from an alien race that had previously built a base on Mars. We didn’t know what it was that we were supposed to learn, because the aliens were difficult to communicate with.
They were trying to teach us something. They kept flying in, showing us some procedure they did at their base, and then leaving. They operated these machines that pumped sand.
It was me that figured it out, though! They had a way to convert the sand to fuel.