From SpaceX website:
WHY MARS?
“At an average distance of 140 million miles, Mars is one of Earth’s closest habitable neighbors. Mars is about half again as far from the Sun as Earth is, so it still has decent sunlight. It is a little cold, but we can warm it up. Its atmosphere is primarily CO2 with some nitrogen and argon and a few other trace elements, which means that we can grow plants on Mars just by compressing the atmosphere. Gravity on Mars is about 38% of that of Earth, so you would be able to lift heavy things and bound around. Furthermore, the day is remarkably close to that of Earth.”
“Habitable”? Really? No.
Decent sunlight? Only 44.4% of Earth sunlight, less than half. So until Elon develops better solar panels, efficiency from intensity will be about a quarter, and halve it again for the low temperatures so overall solar panel efficiency will be one eighth maximum.
“We can warm it up” – what does that even mean? Warm up what, the whole planet?
“Its atmosphere is primarily CO2”. True. 95% CO2. But at 0.007 Bar there isn’t much of it. “which means that we can grow plants on Mars just by compressing the atmosphere” False. Plants will die at around 0.5% CO2. Mission: Failed. No food. Everyone died.
What they don’t tell you. The whole plant is covered in strong, inorganic weedkiller. There is no soil, just dirt and dust. Dust storms last for weeks at a time – no solar at all, no plant growth in the window boxes. No water. No oxygen. No energy source. No magnetic field, so no protection from dangerous solar radiation or cosmic rays.