A review of existing analog habitats and lessons for future lunar and Martian habitats

Many space agencies have recently agreed on the Moon as the next step in human space exploration, and impressive progress is being made with regard to transportation, particularly launch and lander technologies. Meanwhile, a number of simulation habitats have been built and occupied by volunteer crews in order to study the human factors involved with life on the Moon or on Mars. The number of such habitats is ever increasing, and we believe it to be both necessary and helpful to provide an overview of what is already existing and what lessons in habitat design have already been learned from tests with human inhabitants. In this paper, we therefore review (1) the active analog habitats published in the English-speaking literature, (2) a selection of inactive, but pioneering analog habitats, and (3) a selection of research bases in extreme environments such as Antarctica that have not primarily been built for spaceflight simulations but provide interesting insights nonetheless. Specifically, we explore the architectural concepts incorporated and tested in existing habitats, technologies already implemented, and the scientific questions addressed. Our goals are twofold: (1) provide a guideline to researchers who seek a simulation facility for their research questions, and (2) advise the construction of future habitats for simulations and, ultimately, for missions to the surface of the Moon or Mars.