Use of a Robotic Testing Device to Investigate the Effects of Sizing on Space Suit Joints

The return of astronauts to the moon and the future plans for a trip to Mars will lead to an increase in mission duration and an emphasis on surface Extra-Vehicular Activities (EVAs). To make the most of these extended missions an advanced EVA space suit system will be needed. One way to increase astronaut performance through the design of an improved space suit could be sizing the space suit to the individual astronaut anthropometrics. This would reverse the current trend in USA EVA space suits of standardization and a decrease in available component sizes. To determine the benefit of a custom-sized suit system, work needs to be done to identify the potential benefits of individual sizing. Using data collected using the Modular Anthropomorphic Robotic Spacesuit (MARS) joint tester the effect of suit sizing on mobility can be investigated. The MARS joint tester is a space suit joint testing device developed at the University of North Dakota. The testing device replicates the mechanics of a human arm moving a pressurized spacesuit joint while measuring the torque induced on the human-shaped robotic arm by the pressurized space suit arm assembly. The device is modular in that different sized arms can be attached to the system replicating a wide range of anthropometry. The pressurization interface of the tester is designed in such a way as to accommodate a range of space suit joint geometries. With the MARS joint tester, a range of arm sizes can be tested using several spacesuit joints of varying sizes. Preliminary work and has been done using the anthropometry of a roughly 95th percentile male, and will later be supplemented with additional data, from a range of anthropometries.