Long-term human tolerance to partial gravity (<1g)

Determine whether humans can tolerate long-term exposure to partial gravity levels between 0g and 1g, and ascertain the minimum gravitational level required to prevent microgravity-related health effects during sustained habitation in environments such as the Moon (0.17g) and Mars (0.38g), as well as in large rotating space stations that may provide less than Earth-normal gravity in some regions.

Background

The paper reviews known adverse effects of microgravity on human health (e.g., bone and muscle weakening, cardiovascular issues, immune changes) and describes the use of centripetal gravity in rotating stations to mitigate these effects. While Earth-normal gravity is well tolerated, the acceptability of sustained lower gravity levels remains a critical unknown for mission planning and habitat design.

Planned long-duration missions and settlements on the Moon and Mars will expose crews to 0.17g and 0.38g, respectively. Establishing the minimum effective gravity needed to maintain health is essential for setting design targets for artificial gravity systems and evaluating whether partial gravity environments can obviate the need for full 1g in all habitable areas.