The white rat, Rattus norvegicus has been used extensively in microgravity flights. Initial NASA flight experiments with rats supported the Shuttle Student Involvement Program (SSIP). Hardware to house the rats was called the Animal Enclosure Module (AEM).The AEM for the SSIP, fit into a middeck locker. Potatoes provided water; food bars, glued on the walls, provided nourishment. Waste was absorbed and odor and microbial growth controlled by sandwiched phosphoric acid treated charcoal and filter materials utilizing much of the technology employed in the Rodent Research Animal Holding Facility, a Spacelab piece of equipment. The SSIP AEM potato “watering” system succumbed to mold and had to be replaced by real water contained within plasma bags. A metal enclosure housed the plasma bags between two heavy springs which forced water through animal activated lixits. A water refill box was designed within the Ames Space Life Sciences Payloads Office and utilized initially on Spacelab Life Sciences 1 to resupply water during the extended ten-day mission.AEMs have been utilized by various elements in the Small Payloads program, including the Center for Commercial Development of Space flights. The current configuration of the AEM can provide water, food, and waste management up to approximately 14 days. Missions exceeding that period are in jeopardy in terms of food supply and waste management. With our continuing vision toward Space Station Freedom, every succeeding Shuttle and Spacelab mission has increased in duration. Currently one middeck rodent experiment is manifest on SLS-3 (a 20-day mission scheduled for early 1996). In addition, an experiment requiring electromyograph (EMG) is being assessed for SLS-4. Other experiments have been presented requiring access to animals in these miniature housing units. This paper addresses the development of an Advanced Animal Habitat to accommodate experiments of the future and their needs for support to: Long duration missions Data collection Animal access Interchangeable specimen chambers.