[theK]

I think putting any amount of tons of matter into stratospheric altitude is a hard challenge.

Especially if we consider the fact that you would be putting upwards of 200t[0] of CO2 into roughly the same altitude Only to deliver maybe 5 tons of sulfur.

[0]: https://www.theguardian.com/science/2021/jul/19/billionaires...

[nine_k]

But we don't need to do that excessively fast. How about a stratospheric balloon? Balloons reach 30-40 km for weather observation purposes.