Flexible Spacesuits for the Exploration of Mars
Abstract: Current gas-pressurised space suits are bulky stiff shells severely limiting astronaut function and capability. The rigidity of these so-called ‘soft’ suits is due to the high pressure differential between the interior of the suit and the exterior environment, causing the air-tight layers to inflate into a taut neutral position. Research into new materials have produced mild improvements over the last 30 years, but the simple motion of clenching a fist in the current suit is still likened by astronauts to squeezing a tennis ball. More recent efforts using external electromechanical actuators reduce required bending torques but present many more problems. As the dilemma of solving rigidity persists, it seems gas-pressurised suits will severely hamper all external field operations on Mars.
An alternative approach to pressurisation using mechanical counter pressure (MCP) may improve the flexibility of extravehicular suits. An MCP suit would exert pressure on the body (except the head) by form-fitting elastic garments. A standard helmet would be worn to provide both pressurisation to the head and oxygen for breathing. MCP suits have been found to offer dramatic improvements in reach, dexterity and tactility due to the replacement of stiff joints and bearings with light, flexible elastics. Recent studies have concluded that prototype MCP gloves compress the hand at similar levels to current gas-pressurised suits and effectively protect the hand physiologically when worn in a vacuum chamber.
MCP suits, though unproven, offer many more improvements over current suits such as safety (as a tear or hole would remain a local defect rather than cause a catastrophic puncture), lower suit costs and vastly reduced weight and volume (including the life support systems), low susceptibility to dust (as bearings are not required) and highly durable materials.
PROFILE: James Waldie was a Research Scholar at the University of California San Diego's Space Physiology Laboratory, and is currently finishing his PhD in Aerospace Engineering at RMIT University. He was involved in a NASA/Honeywell project to develop experimental spacesuits made of elastics and to study any physiological effects they caused. Such elastic experimental suits could be lighter, safer and more flexible than current gas-pressurised suits, which make them ideally suited for use on Mars. He was also looking at how to make elastic intravehicular spacesuits more comfortable in space, both to function as a launch and re-entry suit, but also as a countermeasure to long duration physical deconditioning. James is also project manager for Mars Society Australia’s MarsSkin Project.