Aboard the International Space Station astronauts experience a micro-gravity environment: the weight of humans and objects appears to be absent, thanks to the absence of stress and strain normally resulting from externally applied, mechanical contact-forces. This weightlessness has adverse effects on the human neural system, cardiovascular system, and musculoskeletal system. Firstly, regarding the neural system, two major problems arise, mainly because of the absence of the ground reaction force: a confusion of the vestibular system, and a possible deterioration of the neural model of posture and locomotion. Secondly, the main cardiovascular problem that arises, because of a fluid redistribution to the upper body, is an inability to maintain blood pressure towards the lower extremities. Thus, orthostatic intolerance and hypotension occur upon return to Earth. Last but not least, as a result of the absence of mechanical stresses on muscles and bones, skeletal muscles weaken, bone tissue deteriorates, and the astronaut's spine elongates.
To solve these problems, we came up with the concept of the Space Gravity Suit. Our solution is a novel, intra-vehicular activity Suit that exerts mechanical loads on the astronaut's body, through the structural tension of its fiber matrix, to partially replicate the gravitational stress that would be felt on Earth. It seems reasonable for the Suit to be composed of at least two layers: one, inner, skin-tight layer to compress the astronaut's body and assist in fluid distribution towards the lower extremities, and a second, external, resistive layer to elevate the mechanical load on weight-bearing bones, by an application of elastic forces, and, perhaps, assist in partially emulating the ground reaction force. For the first layer, off-the-shelf materials are already available: spandex, latex, nylon. Electroactive polymers could be used as the basic fiber material of the second layer, since they can be controlled in real-time with a suitable microcontroller.
The Space Gravity Suit will eliminate muscular and bone loss, while at the same time it will maintain the positive pressure on the lower body and prevent orthostatic intolerance. Furthermore, it will maintain the neural model of the ground reaction force and it will also prevent gait abnormalities and spine elongation, thus eliminating back pain and fitting problems with EVA suits. Last but not least, it will minimize the exercising time and will free up the astronauts’ time for other activities. Regarding its manufacturability, for the external, resistive layer, a 3D scanning and 3D printing customization solution is currently being considered, since additive manufacturing of electroactive polymers is already proven in the literature. For the inner, skin-tight layer, off-the-shelf apparel manufacturing methods seem to suffice. The aforementioned materials are low-cost, so the production cost is not expected to be prohibitive.
The Suit’s marketing strategy will primarily target the beachhead market of the Astronaut Corps via a B2G approach. A B2B approach to target corporate astronauts of future private space stations will also be considered. Finally, via a B2C approach it could be possible to target terrestrial spin-off markets, such as patients with osteoporosis, muscle dystrophy, or professional athletes.