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Issues on human acceleration tolerance after long-duration space flightsThis report reviewed the literature on human tolerance to acceleration at 1 G and changes in tolerance after exposure to hypogravic fields. It was found that human tolerance decreased after exposure to hypokinetic and hypogravic fields, but the magnitude of such reduction ranged from 0 to 30 percent for plateau G forces and 30 to 70 percent for time tolerance on sustained G forces. A logistic regression model of the probability of individuals with 25 percent reduction in +Gz tolerance after 1 to 41 days of hypogravic exposures was constructed. The estimated values from the model showed a good correlation with the observed data. A brief review of the need for in-flight centrifuge during long-duration missions was also presented. Review of the available data showed that the use of countermeasures (such as anti-G suits, periodic acceleration, and exercise) reduced the decrement in acceleration tolerance after long-duration space flights. Areas of further research include quantification of the effect of countermeasures on tolerance, and methods to augment tolerance during and after exposures to hypogravic fields. Such data are essential for planning long-duration human missions.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Kumar, K. Vasantha
(Krug Life Sciences, Inc. Houston, TX., United States)
Norfleet, William T.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1992
Subject Category
Aerospace Medicine
Report/Patent Number
NAS 1.15:104753
Accession Number
Funding Number(s)
Distribution Limits
Work of the US Gov. Public Use Permitted.
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