National Aeronautics and Space Administration
The PLSS is equipped to support astronauts for a seven hour EVA with an hour contingency; however, the actual maximum length of the EVA is determined by the individual metabolic rate of the astronauts and the thermal environment of the EVA. The EMU is designed to accommodate an EVA mission consisting of the following characteristics: a) Total duration of 7 hours maximum under nominal solar exposure or 6 hours maximum under the worst case solar exposure. b) An average crewmember metabolic rate of 1000 Btu/hr for 7 hours or 850 Btu/hr for 8 hours. c) Peak crewmember metabolic rates of 2000 Btu/hr for 15 minutes and 1600 Btu/hr for 1 hour at any time within the EVA. d) Minimum rate of 350 Btu/hr for 30 minutes after an average work rate of 1000 Btu/hr and followed by a rate of 700 Btu/hr for up to 30 minutes. The EMU major subsystems, the Primary Life Support Subsystem (PLSS), the SOP and the Space Suit Assembly (SSA), and other associated support and ancillary equipment are shown schematically in Figure 3-3.
Figure 3-1. NASA EMU High-Level Description Illustrating Components of EMU Pressure Garment and Life Support Assemblies
Published on Feb 27, 2014
Report of the NASA Mishap Investigation Board examining the high visibility close call event of July 16, 2013 when ESA astronaut Luca Parmit...