With the advent of the Space Station Program, regenerative Environmental Control and Life Support Systems (ECLSS) are being considered to minimize logistics requirements. In addition to the potential to improve system performance and reduce life-cycle costs, rationale for adopting regenerative techniques . is based on sixteen years of National Aeronautics and Space Administration (NASA) sponsored regenerative ECLSS hardware development. This technological progress has been obtained through the Space Station Preprototype (SSP) and the Regenerative Life Support Evaluation (RLSE) programs, and ongoing Advanced Preprototype subsystem development and testing.The SSP program focused on regenerative life support techniques to satisfy projected goals of long-duration earth orbital missions. Although the program was prematurely terminated by a funding redirection, portions of the regenerative Atmospheric Revitalization Group (ARG) and Water and Waste Management Group (WWMG) were delivered to the NASA Johnson Space Center (JSC) for evaluation. The RLSE program continued to pursue this technology through fabrication of second generation ARG and WWMG subsystems that were tested at NASA JSC. Alternate technology advancement for major ARG and WWMG subsystem elements is being accomplished by individual advanced preprototype subsystem development.In concert with the technology programs, an Advanced Environmental Control System (ECS) test laboratory designed to accommodate the unique requirements presented by regenerative ECLSS has been operational for twelve years. Technologies for six and three-person oxygen generation, carbon dioxide removal, carbon dioxide reduction, phase change urine reclamation, hyperfiltration wash water reclamation, water quality monitor, organic content monitoring, and post-treatment have been characterized as subsystems and integrated ARG and WWMG systems. The thousands of hours of “hands on” experience gained through comprehensive testing has proven to be a valuable means for identifying subsystem’s technology areas requiring improvement for directing follow-on NASA development programs.