A series of tests by NASA at the Johnson Space Center to support the concept that a human life-support system can be devised for space travel to supply food, water, and oxygen indefinitely by using regenerative or recycling technologies.

The first test, then known as the Early Human Testing Initiative (EHTI Phase I), was conducted in August 1995 in a closed 3-m variable pressure growth chamber (VPGC) to show that a crop of wheat could revitalize air for 15 days. The second test, LMLSTP Phase II, took place in June 1996 in a 6-m chamber, the life-support systems integration facility, that recycled air and water for a crew of four. LMLSTP Phase IIA repeated this for 60 days from 13 January to 14 March 1997 using hardware simulating the International Space Station. The final test, LMLSTP Phase III, which began on 19 September 1997, had the crew complete 91 days in the chamber, the longest duration for a closed-chamber test in the USA. The LMLSTP tests were followed by the Bioregenerative Planetary Life-Support Systems Test Complex (BIO-Plex).