4 ms·

I'm not aware of any vacuum container that is strong enough to resist buckling while being light enough to be buoyant.

elihu 5y ago
Well, you have low pressure and low gravity working both for you and against you in this case. It doesn't have to be very strong, because atmospheric pressure is so low. But also, the lifting power is also very low, so it would have to be far less dense than a vacuum container would have to be to work on earth. Low gravity means you need less lift, but low gravity also means the weight of the surrounding air is less so you need more volume. I guess that cancels out. I suspect it's not practical in atmosphere as thin as Mars, but maybe with a light enough or strong enough material it's possible? At any rate, you'd need an enormous volume just to lift relatively small payloads. And, just filling a balloon with hydrogen would probably make more sense in almost any situation. At least one good thing Mars has going for it in terms of airships is that CO2 is more dense than Earth's atmosphere. Even nitrogen would be a weak lifting gas on Mars (though it's not available in abundance there as far as I know). Wikipedia has some useful background information: https://en.wikipedia.org/wiki/Vacuum_airship https://en.wikipedia.org/wiki/Vacuum_airship
toiletaccount 5y ago
Steel would work on Earth.
dogma1138 5y ago
https://core.ac.uk/download/pdf/161998356.pdf https://core.ac.uk/download/pdf/161998356.pdf They found a design that can work with current materials and lift 500kg worth of payload. >”The tensegrity based design using current materials, accounting for losses due to deflection of the membrane and other factors, is capable of 500 kilograms of payload. If trends in the mass reduction capabilities of the tensegrity beam design continue to higher complexities, which is probable, then implementation of a complexity 4 beam will result in 1 to 1.5 tons of payload capacity. In addition, the tensegrity design has been shown to offer full deployability and can be collapsed for transport to Mars.”

Well, you have low pressure and low gravity working both for you and against you in this case. It doesn't have to be very strong, because atmospheric pressure is so low. But also, the lifting power is also very low, so it would have to be far less dense than a vacuum container would have to be to work on earth. Low gravity means you need less lift, but low gravity also means the weight of the surrounding air is less so you need more volume. I guess that cancels out. I suspect it's not practical in atmosphere as thin as Mars, but maybe with a light enough or strong enough material it's possible? At any rate, you'd need an enormous volume just to lift relatively small payloads. And, just filling a balloon with hydrogen would probably make more sense in almost any situation. At least one good thing Mars has going for it in terms of airships is that CO2 is more dense than Earth's atmosphere. Even nitrogen would be a weak lifting gas on Mars (though it's not available in abundance there as far as I know). Wikipedia has some useful background information: https://en.wikipedia.org/wiki/Vacuum_airship https://en.wikipedia.org/wiki/Vacuum_airship

toiletaccount 5y ago

Steel would work on Earth.

dogma1138 5y ago

https://core.ac.uk/download/pdf/161998356.pdf https://core.ac.uk/download/pdf/161998356.pdf They found a design that can work with current materials and lift 500kg worth of payload. >”The tensegrity based design using current materials, accounting for losses due to deflection of the membrane and other factors, is capable of 500 kilograms of payload. If trends in the mass reduction capabilities of the tensegrity beam design continue to higher complexities, which is probable, then implementation of a complexity 4 beam will result in 1 to 1.5 tons of payload capacity. In addition, the tensegrity design has been shown to offer full deployability and can be collapsed for transport to Mars.”