Straightforward and literal interpretation of the theme, but it obviously works. I like the plot hook of an asteroid on a collision course turning out to be inhabited. Oops. It's maybe not as strong on horror vibes as most Mothership stuff, but that's okay.
The story probably works better with the explosives than the engines, although then it might leave the players wondering why they have to land on it and can't just shoot it with a missile.
The visual design is spare but functional. The maps are a bit confusing in that they both use numbering and then the location descriptions are all on the same page together. I might use letters for one and numbers for the other.
There's a significant usability issue in having the interior map (the more elaborate of the two) on the opposite side of the sheet from the location descriptions. That's going to be a lot of flipping. You could fix that by putting the interior location descriptions on the left panel of the spread instead of the right... then with the cover open but the flap closed, you'd have the interior map and interior descriptions next to each other.
Plotwise, I can see this being a lot of fun once the players are in contact with the cult and entering the asteroid. I like that they have options to just fight through the scenario and blow everything up, or try to persuade the cult to help find a non-destructive way to divert the asteroid and get a "good" ending.
However, I see one problem there in that it's not obvious why the players would go inside. Some players might just shoot the first group of cultists, finish setting up their explosives, and take off, without ever learning anything more. You're kinda counting on the players to "play along" and show some curiousity (or ethics) for the sake of the plot. But that can make them feel railroaded if they think their characters would take the shortcut, but know that it would mean not really having an adventure.
I would suggest altering the plot slightly to force a trip inside. If you're going with explosives, maybe the mission-givers can tell the asteroid is hollow. They don't have enough explosives to blow it up from the outside, but planting some inside should work. But first they'll need to install a radio repeater on the surface so the detonation signal can reach the charges. Something like that maybe?