PORTABLE LOW TEMPERATURE COOLER FOR SPACE STATION

A THERMALLY EFFICIENT LIGHTWEIGHT ENCLOSURE (COOLER) FOR LOWTEMPERATURE STORAGE OF BIOLOGICAL AND OTHER EXPERIMENT SAMPLES ONBOARD THE SPACE STATION, AND TRANSPORTATION TO EARTH, WILL PROVIDE SIGNIFICANT LIFE CYCLE COST SAVINGS TO THE SPACE STATION PROGRAM. IN ADDITION, THE CONCEPT IS ESSENTIALLY PASSIVE REQUIRING NO PUMPS AND/OR COMPRESSORS. SAFETY IS ENHANCED BECAUSE POTENTIALLY TOXIC HEAT TRANSPORT FLUIDS ARE NOT REQUIRED. THE COOLER COULD BE REMOVED TO THELOGISTICS MODULE, INSTALLED IN THE APPROPRIATE LABORATORY MODULE, SERVE AS A LOW TEMPERATURE STORAGE CONTAINER, AND WHEN FULL RETURNED TO THE LOGISTICS MODULE FOR THE EARTH RETURN TRIP. THE COOLER WILL INCORPORATE EVACUATED MULTILAYER INSULATION, AND OTHER MATERIALS OF LOW THERMAL CONDUCTANCE TO MINIMIZE THE HEAT LOAD. A PHASE CHANGE MATERIAL WILL BE INCORPORATED TO MAINTAIN THE REQUIRED ENCLOSURE TEMPERATURE. THE SYSTEM WILL INTERFACE WITH THE ONBOARD SPACE STATION ATMOSPHERE MAKEUP FLUID (NITROGEN) WHICH IS STORED SUPERCRITICALLY AT CRYOGENIC TEMPERATURE. THE COLD ATMOSPHERE MAKEUP NITROGEN WILL FLOW THROUGH THE COOLER PRIOR TO ENTERING THE SPACE STATION ATMOSPHERE, PROVIDING THE REFRIGERATION FOR THE 90 DAY STORAGE PERIOD ONBOARD THE STATION. THE THERMAL CAPACITANCE OF THE SYSTEM WILL CONTROL THE ENCLOSURE TEMPERATURE DURING THE ASCENT ANDDESCENT PHASES OF THE TRANSPORTATION PERIOD.