You are on your way to another planet when you lose control of your main ship. You do an emergency evac using your recon ship, R-01, and end up landing in an asteroid belt. You need to gather resources, build a base, terraform the asteroid and defend yourself from different kinds of enemies so you can survive and get back home.
This is a base that I've set up inside of an asteroid. I drilled out the inside of it and have gathered a good amount of water that I'll eventually use for terraforming.