08-17-2016, 03:35 PM
Yep, that's what I'm thinking too. It's like building a tower, or better yet, a bridge (a tension structure) — for a given material, there is a limit beyond which you simply can't build any bigger, because it can't support its own weight.
So, thinking far-future for a moment, reducing gravity is probably a good idea. Just because we evolved in 1G doesn't mean we'll necessarily always need 1G... the Mars advocates certainly don't think so! And reducing the gravity level really helps with the centrifugal stress.
It doesn't help with the pressure vessel, though. For that, we'd probably have to switch from a cylinder to a torus. Then what matters is the minor radius, not the major radius, so you could go a lot bigger overall.
And of course you could also reduce the air pressure. People live quite happily in Denver, which is at about 1/2 atmosphere, so that cuts your pressure vessel thickness in half right there. (Not to mention making it twice as easy for space workers to come and go!
So, thinking far-future for a moment, reducing gravity is probably a good idea. Just because we evolved in 1G doesn't mean we'll necessarily always need 1G... the Mars advocates certainly don't think so! And reducing the gravity level really helps with the centrifugal stress.
It doesn't help with the pressure vessel, though. For that, we'd probably have to switch from a cylinder to a torus. Then what matters is the minor radius, not the major radius, so you could go a lot bigger overall.
And of course you could also reduce the air pressure. People live quite happily in Denver, which is at about 1/2 atmosphere, so that cuts your pressure vessel thickness in half right there. (Not to mention making it twice as easy for space workers to come and go!
Joe Strout
Lead Developer, High Frontier