Mitigating crew health degradation during long-term exposure to microgravity through countermeasure system implementation

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Experience with the International Space Station (ISS) program demonstrates the degree to which engineering design and operational solutions must protect crewmembers from health risks due to long-term exposure to the microgravity environment. Risks to safety and health due to degradation in the microgravity environment include crew inability to complete emergency or nominal activities, increased risk of injury, and inability to complete safe return to the ground due to reduced strength or embrittled bones. These risks without controls slowly increase in probability for the length of the mission and become more significant for increasing mission durations. Countermeasures to microgravity include hardware systems that place a crewmember's body under elevated stress to produce an effect similar to daily exposure to gravity. The ISS countermeasure system is predominately composed of customized exercise machines. Historical treatment of microgravity countermeasure systems as medical research experiments unintentionally reduced the foreseen importance and therefore the capability of the systems to function in a long-term operational role. Long-term hazardous effects and steadily increasing operational risks due to non-functional countermeasure equipment require a more rigorous design approach and incorporation of redundancy into seemingly non-mission-critical hardware systems. Variations in the rate of health degradation and responsiveness to countermeasures among the crew population drastically increase the challenge for design requirements development and verification of the appropriate risk control strategy. The long-term nature of the hazards and severe limits on logistical re-supply mass, volume and frequency complicates assessment of hardware availability and verification of an adequate maintenance and sparing plan. Design achievement of medically defined performance requirements by microgravity countermeasure systems and incorporation of adequate failure tolerance significantly reduces these risks. Future implementation of on-site monitoring hardware for critical health parameters such as bone mineral density would allow greater responsiveness, efficiency, and optimized design of the countermeasures system.

Original languageEnglish (US)
Title of host publicationEngineering Technology management - 2004
Subtitle of host publicationSafety Engineering and Risk Analysis, Technology and Society, Engineering Business Management
PublisherAmerican Society of Mechanical Engineers
Number of pages8
ISBN (Print)0791847209, 9780791847206
StatePublished - 2004
Event2004 ASME International Mechanical Engineering Congress and Exposition, IMECE - Anaheim, CA, United States
Duration: Nov 13 2004Nov 19 2004

Publication series

NameEngineering Technology Management


Other2004 ASME International Mechanical Engineering Congress and Exposition, IMECE
Country/TerritoryUnited States
CityAnaheim, CA

All Science Journal Classification (ASJC) codes

  • General Engineering


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