Metabolic Expenditures During Extravehicular Activity: Spaceflight versus Ground-based Simulation

In general metabolic rates tend to be higher in NBL than in flight: a) Restraint method dependent; b) Significant differences between the NBL and flight for BRT and APFR (buoyancy effects); and c) No significant difference between NBL and flight for free float and SRMS/SSRMS operations. The total metabolic energy expenditure for a given task and for the EVA as a whole are similar between NBL and flight: a) NBL metabolic rates are higher, but training EVAs are constrained to 5 hours; and b) Flight metabolic rates are lower, but the EVAs are typically an hour or more longer in duration. NBL metabolic rates provide a useful operational tool for flight planning. Quantifying differences and similarities between training and flight improves knowledge for preparation of safe and efficient EVAs.