Extra-vehicular activity (EVA) is any activity that an astronaut performs outside the spacecraft, whether it be in microgravity (sometimes known as spacewalking) or on an extraterrestrial surface such as the Moon or Mars. On many microgravity missions such as those on the Space Shuttle or ISS, EVA is the sole means to accomplish certain critical mission objectives; on the Moon or Mars it will be by far the most important means by which future astronauts explore their surroundings.
At the MIT Man Vehicle Laboratory we have been pursuing EVA research for well over a decade. Our previous research has focused on quantifying the capabilities and limitations of the current Space Shuttle spacesuit, known as the Extravehicular Mobility Unit (EMU). We developed analytical models of the EMU and validated these through experiments with a pressurized EMU and state-of-the-art robotic technology (see image on left). The results have been used to enhance astronaut training, increase crew operational efficiency and optimize mission planning.
However, despite being brilliant feats of engineering design, current spacesuits would be cumbersome for use on extraterrestrial surfaces due to their considerable mass, volume and complexity. Being based on a gas-filled pressure suit concept, current spacesuits also considerably restrict the astronaut's range of motion compared to an unsuited human - particularly disadvantageous for extraterrestrial surface traversal where climbing, squatting and other such motions must be regularly performed.
Our current research therefore focuses on developing an EVA system that could exponentially expand the astronaut's EVA capabilities, especially on extraterrestrial surfaces, by providing enhanced mobility and life support based on the concept of providing a 'second skin' capability for astronaut performance. Known as the Bio-Suit, our system (see image on left) is a modular design based on mechanical counterpressure in which the body is pressurized using elastic tension in a skin-tight garment rather the gas in a traditional spacesuit such as the EMU. The inherent simplicity and elegance of the Bio-Suit concept has the potential to simplify life-support system design, reduce the energy expended by the astronaut in using the suit and diminish the risk of depressurization and other EVA hazards.