Mechanical Counter Pressure Space Suits: Advantages, Limitations and Concepts

Gas-pressurised space suits have been highly effective as a life support system, but are a severe hindrance to astronaut function and capability. They are rigid, heavy, bulky, costly, leaky, and require high maintenance due to the complexity of constant volume joints and associated bearings and restraint layers. For future planetary exploration, revolutionary suit designs must be developed to satisfy requirements for a light, durable, puncture resistant, low leakage suit with excellent full-body flexibility. An alternative suit pressurisation technology called Mechanical Counter Pressure (MCP) may provide these required advances by utilizing tight, form-fitting garments to physically compress the body rather than pressurise it with a gas. The only limitations to the MCP approach is the donning, pre-breathe protocol and IVA adaptability characteristics. An active MCP suit, which can relax or tighten as necessary independently on all areas of the body (except the head), effectively addresses these drawbacks without compromising the inherent MCP advantages except for cost. With the advancement of shape-changing materials, an active suit may be produced with electro-active polymer fibres integrated circumferentially into the elastic weave, or shape memory alloy bands aligned in the longitudinal directional. A small, light and flexible suit based on active MCP elastics could be worn for all extravehicular operations, but also during launch and entry.