Multi-ring and variable-gravity layouts

Designs that provide several g-levels at once, or can change g, mainly for research and for acclimatization.

Key results

  • Ways to get several g-levels:
  • Radius steps on one structure. Floors in a baton or cylinder, or nodes on a tether. Carroll's tether facility put nodes at 0.06, 0.16 and 0.38 g (ratios about e) kdhilliard, 2015-02-24. Paul451's G-Lab alternative has 11 levels (4 m each) from Mars g to low g Paul451, 2018-07-16.
  • Spokes of different lengths. A hub with a dozen spokes, opposed pairs at 1, 0.5 and 0.25 g nadreck, 2015-02-23. AGRARIAN's seven arms A_M_Swallow, 2015-10-05.
  • Several rings at different radii. JohnFornaro's 1 g rim plus Mars and lunar sub-rings JohnFornaro, 2022-09-07. whitelancer64 added 0.5 and 0.75 g rings whitelancer64, 2022-10-04. Paul451 proposed 7 m and 5 m main rings at two radii, with 3 m utility tubes alongside Paul451, 2024-01-28.
  • Counter-rotating nested rings. Each ring's g depends on its own rpm relative to inertial space Paul451, 2016-01-14.
  • Change the rpm. Spin runs at 1.7, 2.6 and 4.3 rpm for a baton Paul451, 2022-11-01. Stations that spin down periodically for microgravity runs and up for set-up and harvest mikelepage, 2025-04-12.
  • Deliberately unbalanced dumbbells (lunar g one end, Mars g the other) Paul451, 2022-10-11.
  • A fixed diameter, tested at different rpm Paul451, 2015-03-31:
    • 200 m diameter: Earth g at 3 rpm, Mars at 2, Moon just over 1.
    • 30 m diameter: 8/5/3 rpm.
  • Paul451's view: multiple rings at different radii give more "bang for buck" than separate stations for each g-level Paul451, 2024-01-30. The best early station gives access to any radius, not an arbitrary single g, so variable-g research is always possible Paul451, 2025-09-09.
  • Recent designs with deliberate g-steps:
  • Jerry Stone's Island Zero: modules at 1.0, 0.9, 0.8 and 0.7 g lamontagne, 2026-07-08.
  • Vast's retracted wheel image: inner modules at about 1/3 the radius of the outer, so Mars g outer and lunar g inner LMT, 2024-08-03.
  • Peter_GST's design put all AG on one 0.61 g ring. Paul451 argued it should be "inside out", with the large modules as spokes Paul451, 2025-09-09.
  • Transfer between rings needs elevators or transfer rings. lamontagne's transfer rings, which match either the spindle or the ring, avoid rotating seals lamontagne, 2018-08-04. Paul451 counted each transfer ring as another semi-independent station, with its own bearings and friction Paul451, 2015-11-15.

Open questions

  • Is one variable-g facility enough for the world (Peter_GST: "only one needed, really")? Peter_GST, 2025-09-10
  • How do fluids, ECLSS and plumbing behave across many g-levels in one station?

Sources

Forum posts

  • nadreck, 2015-02-23 (reply #390): Multi-spoke hub, pairs at 1/0.5/0.25 g. Post.
  • kdhilliard, 2015-02-24 (reply #392): Carroll tether nodes at 0.06/0.16/0.38 g. Post.
  • Paul451, 2015-03-31 (reply #558, 1 like): Fixed-diameter g test. Post.
  • A_M_Swallow, 2015-10-05 (reply #667): AGRARIAN arms. Post.
  • Paul451, 2015-11-15 (reply #772): Transfer rings = more semi-independent stations. Post.
  • Paul451, 2016-01-14 (reply #823): Nested ring g depends on own rpm. Post.
  • Paul451, 2018-07-16 (reply #949): G-Lab alternative: 11 levels Mars g → low g. Post.
  • lamontagne, 2018-08-04 (reply #1144): Transfer rings match spindle or ring. Post. Attachments: Station3c.jpg, Station3d.jpg.
  • JohnFornaro, 2022-09-07 (reply #1760): JohnFornaro ring with 1/3 and 1/6 g sub-rings. Post.
  • whitelancer64, 2022-10-04 (reply #1850, 1 like): Add 0.5 & 0.75 g rings. Post.
  • Paul451, 2022-10-11 (reply #1977, 2 likes): Unbalanced dumbbell. Post.
  • Paul451, 2022-11-01 (reply #2293): Baton run plan. Post.
  • Paul451, 2024-01-28 (reply #4427): Two rings at different radii. Post.
  • Paul451, 2024-01-30 (reply #4437, 1 like): Multiple rings > separate stations per g. Post.
  • LMT, 2024-08-03 (reply #4700): Vast wheel: inner/outer radii ≈ Mars/lunar. Post. Attachments: inner and outer radii on wheel station.png.
  • mikelepage, 2025-04-12 (reply #4852, 2 likes): Spin down for µG runs, up for set-up (2 likes). Post. Attachments: SpinStationTorqueCalcs1b.xlsx.
  • Paul451, 2025-09-09 (reply #4945): Early station should allow access to any radius. Post.
  • Peter_GST, 2025-09-10 (reply #4947): Only one variable-g facility needed. Post.
  • lamontagne, 2026-07-08 (reply #5072, 1 like): Island Zero modules at 1.0/0.9/0.8/0.7 g. Post. Attachments: Module Assembly_e.jpg, Image15_000.jpg.