Establishment of a closed artificial ecosystem to ensure human long-term survival on the moon

Bioregenerative life support system (BLSS) is a critical technology maintaining long-term human survival on the Moon or other extraterrestrial bodies. In the current study, we carried out a 370-day integrated high-closure experiment ("Lunar Palace 365" experiment) on the Earth in an upgraded ground-based BLSS experimental facility called "Lunar Palace 1". This experiment was designed to develop techniques to run and adjust system stability under long-term operation and crew shift change conditions. Eight volunteering crew members were divided into two groups with three time phases: Group I stayed in the cabin for the initial 60-day phase; Group II inhabited the cabin instead for a record-breaking duration of 200 days as the second phase; Group I re-entered the cabin, replaced Group II and stayed for the last 105 days. Our results demonstrated the BLSS had excellent stability with a material closure degree of 98.2%. Levels of O2, CO2 and trace harmful gases were well controlled within ranges optimal for crew health and plant production. The system exhibited a strong robustness and could quickly minimize effects of disturbances through self-feedback adjustments. The efficiency of plant production completely met the crews need of plant-based food. The purification efficiency of domestic and sanitary wastewater was up to irrigation standards, and the recovery rate of urine and solid waste achieved 99.7% and 67%, respectively. These results are valuable for further optimization of the BLSS in a lunar base and computer simulations of similar systems.