I think I've come up with decent lore for moon stuff. Let's say the year is 2106 but feel free to suggest another date.
Ok, so the moon's been colonised and a mine for He-3 has been constructed. The other materials are found on Earth and it's cheaper to get native variants so mining for anything else there isn't really a thing. Fusion reactors don't use much fuel but they're very expensive to build and maintain so there aren't many, meaning the singular mine was enough to supply the reactors. The mine itself has been running for a few decades which has caused it to suffer wear-and-tear. It need constant parts and maintenance and was due for refurbishment soon.
Enter Hell. Some of the miners went crazy, parts stopped coming in so things just started to break, miners died, food stopped coming in, all miners died, the mine broke even more, and now only a small part of the mine can be used for mining. The players can choose to activate the mine and get fuel from it but they'll have to spend resources to keep it operational.
As for resources, satellite-harvesting can be done with the right tech or a decent luck roll. The ship the players are on doesn't have very good sensors so they'll have to be relatively close to them to harvest them. Asteroid-mining is downright impossible, though. The tech just doesn't exist that allows for flight to an asteroid to be quick, reliable, and cheap enough to allow for asteroid-mining. The ship the players are on don't even have good enough sensors to find them, anyway.