As part of the overall technology development effort, a series of tests were performed called the Lunar-Mars Life Support Test Project (LMLSTP), formerly known as the Early Human Testing Initiative (EHTI). The first test, EHTI Phase I, was performed in August 1995, in the 10-foot chamber, known as the Variable Pressure Growth Chamber, located at the Johnson Space Center (JSC). The second test, LMLSTP Phase II, was performed in June 1996, in a 20-foot chamber, known as the Life Support Systems Integration Facility, also located at JSC.
The LMLSTP Phase IIA, begun on January 13, 1997, and was the third human test to validate regenerative life support technologies. This test used hardware representative of what was to be used on the International Space Station. As in Phase II, this was an integrated test recycling the air and water required for a crew of four. This test was for 60 days. The test was successfully completed on March 14, 1997.
The final study, LMLSTP Phase III, was a 90-day test that began in September 1997. The study consisted of four crew members and two test chambers connected to each other by gaseous air exchange. The crew lived in the Integrated Life Support Systems Test Facility (ILSSTF) with oxygen augmented by oxygen produced by wheat growing in the Variable Pressure Growth Chamber (VPGC) and carbon dioxide produced by the crew being transferred from the ILSSTF to the VPGC for uptake by the wheat during growth.
A unique bioreactor designed and built at JSC was the primary component of the water recycling process -- it used microbes to clean-up the water. For the first time in this series of tests, an incinerator was used in the solid waste processing system to turn crew fecal matter into ash and gaseous carbon dioxide products for reuse by the wheat.
A Product Gas Transfer System, with components between and interfacing with both chambers, was responsible for gaseous exchange between the ILSSTF and the VPGC to correctly balance the oxygen and carbon dioxide for the crew in the ILSSTF and the wheat crops in the VPGC. Included in this gaseous exchange was the use of the carbon dioxide collected in the VPGC airlock from the incinerator for use by the wheat crop, and use of oxygen generated by the wheat for the incinerator.