Advanced regenerative Environmental Control and Life Support System (ECLSS) technology was identified by NASA as enabling for space exploration. Low Earth Orbit (LEO) mass savings of over 700,000 pounds (320,000 kg) per year are expected for a lunar outpost crew of eight as compared with ECLSS systems which are currently flying. This paper explores ECLSS technologies which show promise for reducing LEO mass for long range exploration initiatives. The roles of In-Situ Resource Utilization (ISRU) and a Closed Ecological Life Support System (CELSS) are discussed. Physical-chemical candidates for advanced technological development are recommended based on combined expendable, consumable and installed subsystem LEO mass savings for a number of advanced water processing and air revitalization approaches. These processes include: (1) higher efficiency urine processing with or without pretreatment, (2) a single water processor for potable and hygiene water, (3) obtaining potable water and oxygen from the electrolysis system, 4) chemical N2 storage and (5) membrane gas separation processes. The benefits of these technologies for increasing loop closure on N2, O2 and H2O are discussed.