Last Published:  03/26/21 03:33:57 PM (Central)
Responsible Element: Human Health Countermeasures (HHC)
Status: Open
Present state of knowledge: Upon return to Earth from a long-duration spaceflight mission, all astronauts demonstrate significant decrements in functional performance, that are most severe in the first 24 hours after landing and resolve over the first 2 weeks as they undergo readjustment to gravity. These decrements are seen despite a comprehensive system of in-flight countermeasures such as exercise, which for most crewmembers allows maintenance of muscle strength and aerobic capacity. However, the most significant contributors to the postflight functional challenges are the deficits seen in the neurovestibular / sensorimotor system that can take days or weeks to recover, and for this type of deficit there is currently no operational countermeasure (though several are under development). The consequences of these postflight deficits are minimal when crewmembers return to Earth and land on firm ground, as they are met at the landing site with ground rescue forces who assist them with vehicle egress and other postflight activities. The situation will be different with future landings on the Moon and Mars, where the crew will need to function autonomously shortly after landing, as well as in near-future water-based landings on Earth, where off-nominal conditions may delay the arrival of support personnel. Understanding and quantifying post-landing functional capacity is necessary to design concepts of operation for Moon and Mars exploration missions. Important components of postflight capabilities include the ability to perform an unassisted capsule egress and conduct critical planetary extravehicular activity (EVA) tasks within the first 24 hours after landing. Understanding the limitations to safe crewmember postflight activities will allow development of needed countermeasures as well as enable setting standards and operational procedures.

Research approach: Upcoming and future flight studies (including the upcoming 1-Year Mission Project and Artemis missions) will characterize physiologic metrics of EVA performance immediately after prolonged weightless flight (when physiology is impaired). Astronauts returning from flight will be studied as they perform mission relevant tasks shortly after returning to Earth, in order to gain an understanding of the challenges involved with performing post-landing tasks such as vehicle egress and EVA, when deconditioned after long-duration of weightlessness exposure and without the benefit of a ground support team.
Target for Closure
Results from postflight EVA simulations as part of the 1YM project will characterize human performance, safety, and challenges of performing an EVA while deconditioned and under the effects of sensorimotor/neurovestibular disruption. Results of similar assessments after Gateway missions and Lunar missions will inform as to the performance when there is exposure to higher radiation levels as well as partial G. These results will then be used to inform countermeasure development, as well as update standards and operational procedures.
Risk Risk of Injury and Compromised Performance Due to EVA Operations
You are here! Gap EVA-101: Determine limitations of EVA performance and physiological metrics shortly post-landing on a planetary surface (with compromised physiology based on flight duration).

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