3 ms·

I assume they’ll eventually just build a big gravitron. The seals would be tricky (I guess the axle it spun on could contain a ladder and door?) Of course the

by hedora 3y ago

I assume they’ll eventually just build a big gravitron. The seals would be tricky (I guess the axle it spun on could contain a ladder and door?) Of course they could simply stop spinning it whenever they needed to open an airlock. (Or just put it in orbit, where these problems are easier to deal with and you don’t need to deal with day/night radiation shielding/heating.)

wongarsu 3y ago
Spin gravity in orbit has its own issues. Most notably you can't anchor the structure anywhere, so won't spin around the spin axis you want but around its center of mass. A center of mass that will shift as people move around, equipment is moved, etc. Another issue is that you need a certain scale, otherwise the Coriolis force as well as differential gravity (the gravity at your feet being higher than that at your head) lead to disorientation and comfort issues. The lower limit seems to be about 40 feet, incidentally the size of a typical graviton on carnival on earth. That's quite a bit wider than the typical rocket, and for now we are much more comfortable with assembling stuff in a gravity well than in orbit.
- WalterBright 3y ago
  > That's quite a bit wider than the typical rocket You can have two habitats connected by a center tube, like an I. Rotate about the center of the I. Or a habitat and a cable connected to a counterweight. It's not really necessary to build a wheel.
  - estebank 3y ago
    In orbit, you don't even need the tube, it can be a single habitat with retractable cables attached to a counterweight of useful material that isn't immediately needed.
- dr_dshiv 3y ago
  It could be a blown up multiwalled sphere with the heavy equipment in a solid cylinder in the middle. The walls would naturally be a bit bouncy, if under the pressure of the internal air. A big arena for playing professional sports could make a significant amount of money through televised sporting events.
- gmueckl 3y ago
  The rotation axis could be stabilized actively by shifting counterweights. But the dynamics of the structure change depending on whether the counterweights move radially or tangentially. Rotation speed would fluctuate slightly in either case. This sounds like an interesting control problem!
kevin_thibedeau 3y ago
Just put a centrifuge under a static dome. No seals needed.
robbiep 3y ago
In the Luna series they discuss this, they basically have a central axis where you enter and then can 'step' up higher to faster spin rates/more gravity (basically a tapered cone)

by hedora 3y ago

wongarsu 3y ago

Spin gravity in orbit has its own issues. Most notably you can't anchor the structure anywhere, so won't spin around the spin axis you want but around its center of mass. A center of mass that will shift as people move around, equipment is moved, etc. Another issue is that you need a certain scale, otherwise the Coriolis force as well as differential gravity (the gravity at your feet being higher than that at your head) lead to disorientation and comfort issues. The lower limit seems to be about 40 feet, incidentally the size of a typical graviton on carnival on earth. That's quite a bit wider than the typical rocket, and for now we are much more comfortable with assembling stuff in a gravity well than in orbit.

WalterBright 3y ago
> That's quite a bit wider than the typical rocket You can have two habitats connected by a center tube, like an I. Rotate about the center of the I. Or a habitat and a cable connected to a counterweight. It's not really necessary to build a wheel.
- estebank 3y ago
  In orbit, you don't even need the tube, it can be a single habitat with retractable cables attached to a counterweight of useful material that isn't immediately needed.
dr_dshiv 3y ago
It could be a blown up multiwalled sphere with the heavy equipment in a solid cylinder in the middle. The walls would naturally be a bit bouncy, if under the pressure of the internal air. A big arena for playing professional sports could make a significant amount of money through televised sporting events.
gmueckl 3y ago
The rotation axis could be stabilized actively by shifting counterweights. But the dynamics of the structure change depending on whether the counterweights move radially or tangentially. Rotation speed would fluctuate slightly in either case. This sounds like an interesting control problem!

kevin_thibedeau 3y ago

Just put a centrifuge under a static dome. No seals needed.

robbiep 3y ago

In the Luna series they discuss this, they basically have a central axis where you enter and then can 'step' up higher to faster spin rates/more gravity (basically a tapered cone)