1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I Would space stations of sci-fi fame actually work?

  1. Sep 1, 2016 #1
    Would a spinning space station as depicted below that use centrifugal force to create artificial gravity actually work? I'm thinking that it would not, this is because the centrifugal force would not affect an astronaut inside unless he was actually fastened mechanically to the hub. The fact that it is only used in sci fi and not sci reality is another indication to me that it is not viable as an artificial gravity tool for space station inhabitants.


    latest?cb=20151110142655.png
     
  2. jcsd
  3. Sep 1, 2016 #2

    jedishrfu

    Staff: Mentor

  4. Sep 1, 2016 #3
    So i found an acceptable subject, good. I do think of it as water in a bucket, but the water in question is in zero (or micro) G. I see it as an astronaut just floating around while the space station walls are spinning around him. I just noticed you have a link, I have to post to be able to look at it. BRB
     
  5. Sep 1, 2016 #4
    Still nothing to make astronaut adhere to surface. If you are buckeled into a seat on the inside of the hub, and forced to spin with the hull, I can see you experience G at that point. Otherwise unattached you would float off the surface as it spun.
     
  6. Sep 1, 2016 #5

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    In the spinning bucket it is not.

    The astronaut would have to move around with the station, sure. What else do you expect? You don't want to shoot through the space station at high speed (as seen by the astronaut). If the astronaut moves relative to the station at high speeds, they will experience a higher or lower effective gravity, depending on the direction. Typical space station designs for artificial gravity are so large that this effect is small for walking speeds. And if you stand on the outer surface, you feel the artificial gravity downwards, you don't need any attachment.

    Existing space stations don't rotate because (a) this requires some minimal size to be useful, and this size exceeds the current space stations, (b) it is much more complex to build such a space station and (c) most space station experiments want to use the microgravity environment. A small-scale test setup was planned for the ISS but got cancelled due to budget constraints. Here is another proposal.
     
  7. Sep 1, 2016 #6
    Thanks
     
  8. Sep 1, 2016 #7

    PeroK

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Put simply, you would need a lateral force on the astronaut to get her spinning with the spaceship. But, once the spaceship and astronaut reach the required rotational speed, only a centripetal force is required to maintain the astronaut's circular motion. And, that force would feel much like gravity.
     
  9. Sep 1, 2016 #8

    jtbell

    User Avatar

    Staff: Mentor

    Consider the movie "2001: A Space Odyssey", which has a large rotating living-chamber inside a non-rotating spaceship. Astronauts enter the chamber from the rest of the ship via the axis and climb "down" a ladder towards the rim. Holding the rungs of the ladder provides the lateral force.
     
  10. Sep 1, 2016 #9
  11. Sep 1, 2016 #10

    jbriggs444

    User Avatar
    Science Advisor

    If there is air inside the space station then that air will move with the station. Otherwise it tends to swirl around light fixtures, doors and desks and gains speed in the process. If there are astronauts floating in the moving air then they tend to move with it. Otherwise it tends to muss their hair and speed them up in the process.

    Like motes of sediment suspended in water in a test tube in a centrifuge, the astronauts then precipitate out onto the floor.
     
  12. Sep 3, 2016 #11
    Consider a station with a 30 meter radius, and rotational speed at the rim of 10 meters per second. This would have an apparent surface acceleration of v^2/r = 10^2/30 or about 3 meters per second. Roughly Mars surface.

    10 meters per second is roughly 22 mph.

    Now put a bicycle track inside the station. If I ride at 22 mph with the direction of motion, I double my weight. If I ride against the rotation, I lesson my weight. Put a jump in place and do awesome tricks.
     
  13. Sep 3, 2016 #12

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Acceleration scales with velocity squared. You experience 4g, which is quite uncomfortable.
     
  14. Sep 3, 2016 #13
    Good point. But it would be 4 times the effective non moving (relative to the local chunk of station) force or about 1.3 G.
     
  15. Sep 3, 2016 #14

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Ah, you took a Mars-like gravity as baseline, right.
    1.3 g are fine.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted