Astronaut Mass Balance for Long Duration Missions



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49th International Conference on Environmental Systems


Human spaceflight logistics requirements are strongly driven by the daily living needs of the astronauts, including their biological functions. Oxygen, water and food are absolute requirements to sustain life and must be supplied at adequate rates. However, these rates can vary from day to day and from person to person. Beyond the body’s immediate physical needs, water is also required for important health and hygiene functions within the spacecraft. Undesirable weight loss or gain aside, human waste product mass outputs will equal the resource inputs over time, resulting in a mass balance that can be used for planning consumable resources for astronauts. Best planning values, as well as range of variability for inputs and outputs are explored at both the individual physiological level and the spacecraft level. These values are important for design of life support and habitability systems as well as for long duration mission planning. Current spacecraft life support systems are not fully closed loop, but the International Space Station does recycle most of its air and water. The astronaut mass balances at the personal and vehicle level can have different impacts at different levels of system closure. Recommendations are made for a consistent set of values representing a realistic astronaut mass balance over reasonable durations for exploration missions.


Michael Ewert, Johnson Space Center, USA
Chel Stromgren, Binera Inc., USA
ICES501: Life Support Systems Engineering and Analysis
The 49th International Conference on Environmental Systems was held in Boston, Massachusetts, USA on 07 July 2019 through 11 July 2019.


human, mass balance, logistics, metabolic, life support