Elon Musk's idea to colonize Mars isn't to build the most efficient in-space architecture. It's to brute force his way with one way trips to Mars using a massive amount of reusable Starships to repeatedly refuel another Starship that is poorly adapted for inter-planetary travel.
The "rocket CO2 doesn't matter" argument is based on the fact that nobody has reusable rockets right now, so the fuel expenditure is bounded by the cost of the rocket. Elon Musk wants to switch that equation on its head. Meaning e.g. $100 million launch costs no longer means $10 million fuel costs and $90 million rocket costs, it now means 5x $10 million rocket costs and 5x $10 million fuel costs, i.e. 5x more fuel used with the same budget and that fuel is going to emit CO2.
One Starship launch produces 3500 tons. Now repeat this to 1000 Earth to Mars launches. That includes at least 10 tanker launches per ship. Meaning at least 10000 launches per year. That equates to 35 million tons of CO2 for something that has no direct benefit to earth.
If he scaled down his Mars colony ambitions to 10 Earth to Mars launches per year people might turn a blind eye to it.
The "rocket CO2 doesn't matter" argument is based on the fact that nobody has reusable rockets right now, so the fuel expenditure is bounded by the cost of the rocket. Elon Musk wants to switch that equation on its head. Meaning e.g. $100 million launch costs no longer means $10 million fuel costs and $90 million rocket costs, it now means 5x $10 million rocket costs and 5x $10 million fuel costs, i.e. 5x more fuel used with the same budget and that fuel is going to emit CO2.
One Starship launch produces 3500 tons. Now repeat this to 1000 Earth to Mars launches. That includes at least 10 tanker launches per ship. Meaning at least 10000 launches per year. That equates to 35 million tons of CO2 for something that has no direct benefit to earth.
If he scaled down his Mars colony ambitions to 10 Earth to Mars launches per year people might turn a blind eye to it.