Twark_Main: stationary shell with internal centrifuges ("Pokeball")

Design summary

  • Counter-rotating AG cylinders in a stationary shield (2023). An inner fast AG cylinder plus a slowly counter-rotating massive outer shield, giving L = 0; add a non-rotating micro-g core Twark_Main, 2023-01-16.
  • Better: split the AG section into two counter-rotating sections. That gives a stationary micro-g core and outer shield, no vacuum bearings, L = 0, stationary visiting vehicles, and customizable g/micro-g proportions. "If you can't justify the scale, back to the barbell" Twark_Main, 2023-01-18.
  • Air drag between sections makes wind with a lapse rate, which trees need Twark_Main, 2023-03-06.
  • Stationary shell with internal centrifuges. A stationary outer pressure/radiation shell (~sphere), a central microgravity cylinder, and AG ring(s), optionally two counter-rotating Twark_Main, 2023-02-14; Twark_Main, 2023-02-15:
  • Large 0 g and 1 g/Mars-g volumes, unlimited non-spinning docking ports, efficient shielding, zero net L; rotating sections span 1 g to ~0.4 g.
  • Paul451's explanation: a centrifuge inside open air means bearings needn't be vacuum-tight; two counter-rotating centrifuges let the station be reoriented as if nothing rotated Paul451, 2023-02-16; Paul451, 2023-02-14; Paul451, 2023-02-15.
  • Momentum vectors cancel, and torques on the frame are only structural Paul451, 2023-02-17.
  • "How I Learned to Stop Worrying and Love Non-Rotating Outer Hulls": a big sphere + counter-rotating toroids + a zero-g core, with unlimited docks Twark_Main, 2023-05-13.
  • "Zero-g core" (2025). A de-spun section without a sliding vacuum seal; Stewart platforms trim wobbles; 3+ water tanks for large imbalances Twark_Main, 2025-09-14.
  • "Pokeball" (2026, final). Two counter-rotating pseudo-tori suspended in each hemisphere of a non-rotating spherical shield, connected to a non-rotating central zero-g spine Twark_Main, 2026-09-20:
  • Upper level 0.67 g, lowest 1 g; the zero-g spine is only ~16% of volume, so ~80% is at spin gravity.
  • No exterior rotating joints, no leaks from moving interfaces, no stability issues, a non-rotating exterior for docking, the best shielding geometry, cheap re-pointing.

Critiques raised

Open questions

  • At what population does the stationary-shell architecture beat multiple barbells?

Sources

Forum posts

  • Twark_Main, 2023-01-16 (reply #2914): Counter-rotating cylinders. Post.
  • Twark_Main, 2023-01-18 (reply #2967): Two counter-rotating sections. Post.
  • Twark_Main, 2023-02-14 (reply #3301): Stationary shell. Post.
  • Paul451, 2023-02-14 (reply #3304, 1 like): Sketch (1 like). Post. Attachments: Twark's concept.jpg, Concave-vs.-Convex-760x400.jpg.
  • Twark_Main, 2023-02-15 (reply #3306): Detail. Post.
  • Paul451, 2023-02-15 (reply #3311, 3 likes): Washing machine (3 likes). Post. Attachments: washing machine is a space station yo.jpg.
  • Paul451, 2023-02-16 (reply #3325, 2 likes): Clear explanation (2 likes). Post.
  • Coastal Ron, 2023-02-16 (reply #3326): Coastal Ron doubts. Post.
  • Paul451, 2023-02-17 (reply #3327): Momenta cancel. Post. Attachments: counter-rotation and precession.png.
  • Coastal Ron, 2023-02-17 (reply #3328): Precession. Post.
  • Roy_H, 2023-02-17 (reply #3332): Loose items. Post.
  • Twark_Main, 2023-03-06 (reply #3488): Wind for trees. Post.
  • Twark_Main, 2023-05-13 (reply #3703): Non-rotating outer hulls. Post.
  • Twark_Main, 2025-09-14 (reply #4955): Zero-g core. Post.
  • Twark_Main, 2026-09-20 (reply #5160, 1 like): Pokeball (1 like). Post.