Most people pay little heed to breathing. We draw air in and we exhale air out on a regular basis. We understand that our bodies use some of the oxygen that comes in and that some carbon dioxide goes out. While this vague notion is sufficient for life on Earth, it’s far too vague for establishing life on another world. Such as the Moon.
Recently Airbus completed their Advanced Closed Loop System (ACLS) that Japan will later rocket up to the International Space Station (ISS). The ACLS converts ‘waste’ carbon dioxide from breathing and ‘waste’ hydrogen into breathable oxygen and drinkable water. A main benefit of this system is to reduce the demand for water on the ISS. Thus making life on-board much more self-sufficient. And less reliant upon the people of Earth. Who continue to provide over 400 litres of water each year to the ISS.
For any infrastructure development, like for a lunar colony, both the construction cost and the carrying cost must be factored. Consider that in 2018 the ISS flight manifest lists 18 launches. As the ISS is mostly complete then these flights represent the carrying costs. Estimate that each launch cost is $100M. Over $1.8B annually! Thus if new technology can reduce the number of launches by one then it represents a reduction in the annual carrying cost of at least $100M. Which partly explains why people aren’t living on the Moon. Yet. And, why funding is the most critical parameter.