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The first two phases of the Lunar-Mars Life Support Test Project [LMLSTP] involved housing human volunteers in closed chambers that mimic future extraterrestrial life support systems. The Phase I test involved one person living for 15 days in a chamber with wheat as the primary means of air revitalization. The Phase II test involved 4 people living for 30 days in a chamber with physical/chemical air revitalization and waste water recycling. The consequences of closure on microbial ecology and the influence that microbes had on these closed environmental life support systems were determined during both tests. The air, water, and surfaces of each chamber were sampled for microbial content before, during, and after each test. The numbers of microbes on the Phase I habitation chamber surfaces increased with length of occupation.

The ability of the water recovery system (WRS) designed for Phase II of the Lunar-Mars Life Support Test Project to remove viral contaminants was tested by challenging the system with bacteriophages MS-2 and PRD-1. Urine-pretreatment and ultrafiltration/reverse osmosis (UF/RO) steps each reduced the combined density of both bacteriophages from >109 to <1 Plaque-Forming Units (PFU)/100 mL. UF/RO also reduced the bacterial density from 108 to 107 Colony-Forming Units (CFU)/100 mL. Before UF/RO, the predominant species of bacteria in the water were Acinetobacter calcoacetious and Klebsiella pneumoniae; afterward, the predominant species were Burkholderia cepacia and B. picketti. The removal of the bacteriophages and the difference in predominant bacteria across the UF/RO step suggest that the Burkholderia had been established downstream of the UF/RO membranes before the test began.