Design and evaluation of elements of a life support system for mechanical counterpressure spacesuits

Abstract

Mechanical counterpressure (MCP) spacesuits offer several advantages over traditional gas-pressurized suits including lower energy cost of transport, reduced risk of decompression due to suit tear or puncture, and increased astronaut comfort. The BioSuit[superscript TM] is an MCP concept being developed at MIT primarily for planetary extravehicular activity (EVA) on the Moon and Mars. In this thesis we present the initial design and testing of several key parts of the life support system for the BioSuit[superscript TM]. First, a breathing compensation bladder that covers the chest and is pneumatically continuous with the helmet is discussed. This bladder eases the burden of respiration associated with constrictive garments and adapts to the changing volume of the chest to provide equalized pressure across the torso. The initial results of laboratory testing of the airflow and pressure maintenance of a bladder-helmet system on a mannequin are presented. Second, thermal modeling of a BioSuit[superscript TM] EVA on the lunar and Martian surfaces was conducted to assess the performance of MCP spacesuit garments in protecting astronauts from the extreme temperatures and harsh radiation environments of those locations. This modeling included new proposed radiation protection and insulating materials as well as a passive elastic compressive layer. Results were computed for both male and female astronauts, helping to identify suit design differences that will be needed to accommodate both men and women who will conduct future EVAs. This work is used to inform future design requirements for the suit's thermal management system. Overall, this research advances the development of life support systems for a full MCP spacesuit and lessons learned can be applied for future engineering prototypes.