Transitions between g-levels

Moving between rotating and non-rotating sections, and between stations, spacecraft and Earth, may be harder on the body than any single steady state.

Key results

  • Transitions may be the worst part. Moving to and from 0 g brings days of adaptation and illness, so daily commuting between spun and de-spun sections could be worse than a 3–6 month tour hop, 2014-02-18.
  • Adaptation to 0 g takes about a week and varies unpredictably. It does not get easier on return, and the first week of every crew cycle is lost Paul451, 2022-10-31.
  • Twark_Main thinks acclimation takes at most two days, and that barf bags are the fix Twark_Main, 2023-04-04.
  • Habituation persists.
  • Rotating-room habituation is retained for ≥30 days, and ground pre-training is possible. Zero-g-adapted people are less susceptible to cross-coupled stimulation Lampyridae, 2018-07-13.
  • People adapted to zero g show no momentary Coriolis sickness, but there are no data on longer exposures Paul451, 2025-09-08.
  • Switching improves with practice. In biology, repeated switching usually makes transitions faster (drunk goggles, the "backwards bicycle"). That suggests a market in training deep-space crews to switch between g-levels Twark_Main, 2025-09-19.
  • Research focus.
  • mikelepage: the key threshold is adapting to frequent 0 ↔ x rpm switching mikelepage, 2018-07-13.
  • Paul451: DiZio/Lackner reached 10 rpm stepwise. A continuously rotating station offers no gradual spin-up, so re-adaptation to 0 g must also be studied Paul451, 2018-07-13.
  • A "diver's pause" style of repeated-transition study was suggested Paul451, 2015-03-31.
  • Reconditioning for Earth return. A proposed ramp for crews returning from Mars: Mars g → 0.5 g for 6 weeks → 0.64 → 0.80 → Earth. The worst period is around 3 days after landing mikelepage, 2019-03-28.
  • Transit engineering.
  • Elevators take 1–3 minutes to cover 200–900 m Roy_H, 2014-02-20.
  • A 0 g → 1 g transfer at 56 m radius (rim speed ~24 m/s) phases in within about 5 s at 0.5 g acceleration Shevek23, 2019-10-25.
  • With a large enclosed de-spun zero-g core, "a minute or less from 1 g to the microgravity facility" redneck, 2025-09-20.
  • Commuting between two stations. Twark_Main estimated about 2 docking cycles per day versus 2 per quarter, with roughly 2 hours of vestibule leak checks per opening, which makes daily inter-station commuting costly Twark_Main, 2025-09-14. Vultur doubts repeated 0 ↔ g shifting would be desirable, since it may induce space adaptation syndrome each time Vultur, 2025-09-16.
  • Exercise gyms as pulses. Linear "sled" gyms with mid-run flips produce 18–27 rpm pulses, so a constant 4 rpm at 60 m radius should be fine Paul451, 2018-07-08; LMT, 2018-07-06.

Open questions

  • Does alternating between 0 g work and spun rest help or harm long-term 0 g health and adaptation? "We don't have a single data point" Paul451, 2025-09-08.
  • Is gradual spin-up useful? Could stations deliberately change rpm (for example 4 ↔ 5 rpm on a 37 m cylinder) Habitant, 2026-09-17.

Sources

Forum posts

  • hop, 2014-02-18 (reply #68): Transition to/from 0 g is worst part. Post.
  • Roy_H, 2014-02-20 (reply #82): Elevator transit 200–900 m in 1–3 min. Post.
  • Paul451, 2015-03-31 (reply #559): Study repeated transitions (diver's pause). Post.
  • LMT, 2018-07-06 (reply #884, 1 like): Hybrid sled gym, elevator gyms. Post.
  • Paul451, 2018-07-08 (reply #896): Sled flips = 18–27 rpm pulses. Post.
  • mikelepage, 2018-07-13 (reply #911): Key threshold: frequent switching. Post.
  • Paul451, 2018-07-13 (reply #912): Stepwise vs continuous rotation. Post.
  • Lampyridae, 2018-07-13 (reply #915, 1 like): Habituation retained ≥30 days; ground pre-training; less susceptibility in 0 g. Post. Attachments: ScreenShot_20180713114209.png.
  • mikelepage, 2019-03-28 (reply #1415, 2 likes): Re-acclimatization ramp. Post.
  • Shevek23, 2019-10-25 (reply #1687): Transfer vehicle phasing at 0.5 g. Post.
  • Paul451, 2022-10-31 (reply #2278, 1 like): 0 g adaptation ~1 week; first week each cycle lost. Post.
  • Twark_Main, 2023-04-04 (reply #3581): Acclimation ≤2 days. Post.
  • Paul451, 2025-09-08 (reply #4937, 1 like): Coriolis adaptation retained up to a month; zero-g-adapted no momentary Coriolis sickness. Post.
  • Twark_Main, 2025-09-14 (reply #4950): 2x/day docking; 2 h leak check each. Post.
  • Vultur, 2025-09-16 (reply #4971): Repeated µG/g shifting undesirable?. Post.
  • Twark_Main, 2025-09-19 (reply #4986): Switching improves with practice; training market. Post.
  • redneck, 2025-09-20 (reply #4996): Minute from 1 g to µG in enclosed core. Post.
  • Habitant, 2026-09-17 (reply #5118): Switch 4 ↔ 5 rpm on a 37 m cylinder?. Post.