Habitat Design and Assessment at Varying Gravity Levels

For a number of years, the University of Maryland Space Systems Laboratory has been conducting a series of design studies and experimental assessments of space habitat designs. This year, under the support of the NASA Exploration Habitat (X-Hab) Academic Innovation Challenge 2014, UMd is performing two parallel and interrelated studies in habitat design; one-gravity investigation and assessment of habitats based on two vertical cylindrical habitat shells built at UMd under prior studies, and a new investigation of habitability aspects of microgravity and partial gravity designs tested in the UMd Neutral Buoyancy Research Facility. Analytical studies performed by UMd as part of a NASA Exploration Systems Mission Directorate grant on the design of a minimum functional habitat element (MFHE) showed that, for most applications, a vertically-oriented habitat provided better internal utilization than a horizontally-oriented habitat such as those in the International Space Station. Two full-scale vertical cylinder habitat mockups, ECLIPSE (two floors, 3.6 meter diameter) and HAVEN (one floor, 5 meter diameter) were built by UMd for prior habitat studies, and were repurposed for the effort reported here. Various internal layouts for these facilities were developed and evaluated in virtual reality using an Oculus Rift immersive VR system. The interiors of HAVEN and ECLIPSEwere remodeled to reflect the best systems found in VR, and short-term (<1 hour) simulations were conducted to allow a meaningful understanding of habitability issues arising from each design. While one-g habitats provide easy access and an essentially unlimited body of potential test subjects, they do not allow realistic internal motion when simulating a habitat in a partial gravity environment such as Mars or the Moon, much less that of a true microgravity habitat. For that reason, a parallel research effort was conducted using an underwater habitat mockup in the UMd Neutral Buoyancy Research Facility (NBRF). Test subjects equipped with full face mask systems with two-way voice communications performed test procedures using “hookah” rigs to remote air tanks to minimize ballast effects on body dynamics. Small amounts of ballast were adjusted to provide the best simulation of microgravity; body segment parameters were used in conjunction with harness systems for individual ballasting of each of the major body segments to produce realistic simulated gravity effects for intermediate gravity levels such as the Moon or Mars. A dedicated Qualisys 12-camera underwater motion capture system was used to measure body motions and infer forces applied. Of particular relevance for this system are focused studies on aspects of habitat design specific to gravitation levels, such as investigating the best methods of providing access between different levels, and performing specific tasks such as investigating stowage systems and reconfiguring interiors with indigenous material to accommodate changes in the size or makeup of the crew mid-mission.

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