Executive Summary

Team 30 - Wearable Countermeasure

Prolonged exposure to microgravity induces numerous medical complications in the human body. Mechanical unloading and abolishment of pressure gradients and resultant headward fluid shift in the body can lead to cardiovascular and muscular atrophy, bone decalcification, symptoms compatible with intracranial fluid pressure increase, and permanent vision impairment. If humanity is to endure extended voyages to extraterrestrial bodies, these deleterious effects will have to be mitigated. One potential countermeasure which simulates the effects of gravity is the in-flight utilization of Lower Body Negative Pressure (LBNP) therapy.

The current LBNP system flown onboard ISS (the Roscosmos Chibis) suffers from one major deficiency: immobility. For LBNP therapy to be effective in preventing spaceflight associated diseases, astronauts will likely be required to utilize the system for several hours per day, several times per week. The immobility of the suit prevents the users from maintaining a standard operational schedule, making compliance impossible to ensure. (feasibility)

Mobility: flexibility Movement across pressurized joint

This project, sponsored by Dr. Lonnie Petersen at the University of California San Diego, seeks to improve the flexibility and mobility of the system such that it does not inhibit the activity of the user. To date, the LBNP systems prototyped by Dr. Petersen’s lab provide insufficient flexibility and exhibit areas of localized compression which constrict the user’s anatomy in direct opposition of the applied negative pressure differential. The goals of this project are to improve upon these efforts and provide a working prototype that prevents material compression along the length of the leg and allows for over 90° range-of-motion at the knee joint while maintaining an operational pressure differential of 25 mm-Hg.

These goals were accomplished by designing and fabricating a unique, 3D-printed endoskeletal pressure joint encapsulated by an air-tight fabric overlay. The joint design includes a geared hinge mechanism, an articulating kneecap, three overlapping support rings, and calf and thigh exoskeletal supports. The fabric overlay consists of layered nylon and Nomex which provide both pressure sealing and fire-resistance. The final prototype successfully maintains operational pressure and provides a knee-joint range-of-motion of over 110°.