Design of a Multipurpose Extensible Space Habitat - Vanguard

This paper documents recent design activities at the University of Maryland in the engineering development of a multirole habitation system designed for an initial low Earth orbit application, but capable of being replicated for or moved to deep-space locations as well. The design effort started with the development of a set of detailed requirements with specific applicability in parallel for each of four reference locations: low Earth orbit, low lunar orbit, a distant lunar retrograde orbit, and Mars orbit co-orbital with (or moored to) Phobos. Each of these locations has different implications for power, propulsion, and thermal control designs, as well as communications and and associated avionics systems. A series of trade studies examined critical design decisions, such as the choice of inflatable or fixed-shell habitat structure, type and emplacement of power systems, and accommodation for additional modules and/or hosted vehicles. The detailed design of the baseline habitat included trade studies driving the selection of life support systems and other crew accommodations, with emphasis on contingency planning for life support system failures remote from Earth in terms of both distance and time required until resupply. Internal layouts examined alternative placement of crew accommodations, life support systems, airlocks, windows, and other crew systems. Operations issues considered include attitude control system design and analysis, number, location, and type of docking interfaces, energy storage for all potential orbits, as well as transport options for moving the spacecraft between low Earth orbit and other destinations of interest. A critical design factor identified was that of launch vehicle choice, primarily due to volumetric constraints of available payload fairings. The paper also discusses near-term analog studies of habitat designs in virtual reality, Earth gravity, and neutral buoyancy to evaluate and validate habitability design choices.