PLANTS FOR HUMAN LIFE SUPPORT IN SPACE: FROM MYERS TO MARS
Bioregenerative life support systems have been discussed since the writings of Tsiolkovsky in the early 20th century. Central to the concept is the use of photosynthetic organisms to regenerate air and food. Bioregenerative research expanded rapidly in the 1950s and 60s through the work of Jack Myers and colleagues, and focused largely on algal systems. Testing even included space flight experiments by Herb Ward in the 1960s, but bioregenerative research in the USA decreased soon after this. In contrast, the Russian BIOS projects led by Josef Gitelson and Henry Lisovsky maintained a steady pace of bioregenerative research from the 1960s through the 1980s, including tests with human crews lasting up to several months. Around 1980, NASA initiated its Controlled Ecological Life Support Systems (CELSS) Program, which focused on higher plant (crop) testing. In the late 980s through the 1990s, findings from university CELSS researchers were used to conduct tests at NASA’s Kennedy Space Center in a large, atmospherically closed chamber. Related tests with humans and regenerative life support systems were subsequently conducted at NASA’s Johnson Space Center in the mid 1990s, and a large-scale bioregenerative test bed called BIOPlex was planned but never completed. A likely scenario for implementing bioregenerative life support might start with a small plant growth unit to produce some fresh foods for the International Space Station or early lunar missions. The plantings might be expanded for longer duration lunar missions, which would then provide an opportunity to assess concepts for Mars missions, where bioregenerative life support will play a more crucial role.