Quantitative analysis of short-radius artificial gravity parameters to mitigate spaceflight-relevant physiological deconditioning

Abstract

Using artificial gravity (AG) as a physiological countermeasure for astronauts during spaceflight has been discussed and researched for decades; however, today there still exists a lack of optimized AG design. The enclosed work critically analyzes the existing literature of bedrest studies (a ground-based analog of microgravity) to provide insight into the benefit of using AG to counteract physiological deconditioning.Physiological data were extracted from 20+ publications that studied the benefit of AG centrifugation during bedrest of 4–60 days in length. Both AG parameters (i.e., loading level, duration of exposure, presence of exercise, etc.) and the physiological measures investigated varied between studies. To aggregate dissimilar measures, we combined outcomes within each physiological subsystem. Multiple linear regression models were used to analyze each subsystem across studies and determine which AG parameters produced the most effective mitigation of bedrest-induced physiological deconditioning.It was found that AG protocols that applied at least 1g loading at the subject's heart level and included exercise enhanced efficacy. Most important for mitigating physiological deconditioning during bedrest was the duration of daily centrifugation, with 60+ minutes being most beneficial. Finally, applying AG in several shorter sessions was slightly more effective, but also generally more tolerable than one continuous session administered each day.The results of our quantitative analysis of previous studies provide direction for future analog studies and design of on-orbit AG platforms. Further, these data-driven recommendations suggest effective AG solutions that are both physiologically tolerable and technologically feasible, enabling a comprehensive countermeasure to protect astronauts across physiological subsystems during future long-duration space exploration missions.