Mars Spacesuit Mass Requirements
The gravity on Mars is 3/8th of Earth gravity. The latest exploration Extravehicular Mobility Unit (xEMU) designed for lunar exploration is just under 400 lbm. While it would be reasonable for a crewmember to operate the xEMU on Earth’s Moon with 1/6 gravity, related studies have demonstrated that this same suit would not be feasible to operate on the surface on Mars. Studies involving Martian offloading are limited and the few available have demonstrated difficulty in suit operation with current advanced suit prototypes. Furthermore, deconditioning due to a long-term journey to Mars is expected to affect the overall suit mass that a crewmember can operate. This initial study aims to provide an initial mass requirement to bound the Mars spacesuit design within a reasonable range. It is expected that detailed Mars-simulation testing will subsequently refine the estimate to support Martian mission timelines. Considerations such as crew deconditioning due to the long exposure to microgravity, pressure garment system (PGS) weight offloading, restricted mobility increasing metabolic rate, and human fitness and size are combined into an initial assessment. Based on preliminary considerations, 230 lbm is recommended as a starting maximum Mars suit mass, which will be split between the PGS and Portable Life Support System (PLSS) subsystems.