Thanks, that makes sense! Not as limiting as I'd feared. StarShip uses 1,200 tonnes of propellant, SuperHeavy uses about 3,300 tonnes. 45% of that will become

Thanks, that makes sense! Not as limiting as I'd feared. StarShip uses 1,200 tonnes of propellant, SuperHeavy uses about 3,300 tonnes. 45% of that will become water vapor, the rest CO2. Couldn't find what altitude SuperHeavy reaches, let's say 1e6 kg water vapor to upper atmosphere and we get 20,000 Starship launches per year, lifting between two and three million tons. Probably a good bit less water vapor actually gets that high, but on the other hand it's fairly generous to allow a doubling of the water vapor.