A “factory seconds” framework 13 might fit your budget, and you get a laptop that is easily repairable and upgradeable. The 11th gen i7 version that starts at $500 is what I have been using for a couple of years now and still runs great.
They also have refurbished laptops, but those seem to start a little bit more expensive.
Umm, akshually. The Martian atmosphere is already 95℅ CO2. Its cold because the atmosphere is so thin. Its thin because Mars does not have a strong magnetic field like Earth does, so solar winds can strip away bits of the atmosphere. Also, Mars only has about 0.38 times the gravity of Earth, making it easier for gases to escape.