Design and modeling of a Mars space suit

This study investigates a light-weight design for a space suit and life support system for astronauts to wear in the exploration of Mars. Existing space suit designs for the Moon and Earth orbit are far too heavy for use on Mars. The portable life support system makes up the majority of the weight in current designs, and is the focus for reducing suit weight. This study explores the concept of using a selectively permeable membrane as the suit's pressure-retaining structure while serving as a replacement for the complex conventional systems for controlling heat and humidity. Current suits use active systems to maintain the suit temperature, cool the astronaut, and control humidity in the suit air. Heat is rejected to the outside by sublimation of ice to the vacuum. The life support system bypasses the body's natural regulatory capability. Using a selectively permeable membrane allows water vapor to permeate through the pressure retaining bladder and diffuse through the layers of the suit directly to the Mars atmosphere; this system dehumidifies the air and allows the body's own thermal regulation system to cool the astronaut by evaporation of sweat. Modular insulation can be added and removed for comfort, much as a jacket is used on Earth.; A mathematical model was developed to simulate the heat and mass transfer characteristics of the human, the layered suit including selectively permeable pressure bladder and variable insulation, and the Mars environment. The model incorporates metabolic data collected in Leslie Wickman's experiments on walking and running with various loads in simulated reduced gravity. Simulation results for several exploration scenarios are presented, covering the full range of conditions that the first Mars astronauts are likely to encounter. Under all environmental conditions and work loads, the astronaut can maintain a comfortable temperature with moderate sweating by adjusting the modular insulation. A related use of membranes controls carbon dioxide in the suit, replacing the use of a lithium hydroxide scrubber. These systems reduce the life support system mass enough to make a suit light enough for easy mobility on Mars.