AMTEC CONDENSER DESIGN FOR ZERO-G OPERATION

ADEQUATE ELECTRICAL POWER FOR SPACECRAFT OPERATIONS IS A CRUCIAL MISSION TASK. THE ISOTOPE HEAT SOURCES USED IN RADIO-ISOTOPE-THERMOELECTRIC-GENERATORS FOR MANY NASA MISSIONS ARE EXPENSIVE. FOR A GIVEN ELECTRICAL POWER, THERMAL-TO-ELECTRIC CONVERSION WITH AMTEC RATHER THAN CONVENTIONAL THERMOELECTRIC CONVERTERS SHOULD PERMIT REDUCTION OF THE GPHS COMPLEMENT BY A FACTOR OF 3. THE ESTIMATED COST SAVINGS MAY APPROACH $40,000 PER ELECTRIC WATT LAUNCHED. AMTEC OPERATES WITH METALLIC SODIUM AS THE WORKING FLUID AND, UP TO NOW, ALL HIGH-TEMPERATURE, RECIRCULATING AMTEC SYSTEMS HAVE USED GRAVITY TO CARRY THE SODIUM FROM THE CONDENSER WALL TO A SUMP, WHERE AN ELECTROMAGNETIC PUMP RETURNS IT TO THE HIGH-TEMPERATURE ZONE. IN ZERO GRAVITY, WITH A CONVENTIONAL CONDENSER, THIS APPROACH FAILS BECAUSE THE SODIUM DISTRIBUTES ITSELF ON THE CONDENSER WALLS AND FAILS TO REACH THE PUMP INLET. FOR AMTEC SPACE OPERATION, OTHER MEANS OF SODIUM CONTROL AND CIRCULATION MUST, THEREFORE, BE DEVELOPED. THE APPROACHIN THIS PROJECT USES A WICK STRUCTURE TO COLLECT THE SODIUM CONTINUOUSLY AT THE CONDENSER AND DELIVER IT TO THE INLET OF AN ELECTROMAGNETIC PUMP. THE PUMP THEN RETURNS THE SODIUM TO THE HIGH-TEMPERATURE ZONE. ADEQUATE ELECTRICAL POWER FOR SPACECRAFT OPERATIONS IS A CRUCIAL MISSION TASK. THE ISOTOPE HEAT SOURCES USED IN RADIO-ISOTOPE-THERMOELECTRIC-GENERATORS FOR MANY NASA MISSIONS ARE EXPENSIVE. FOR A GIVEN ELECTRICAL POWER, THERMAL-TO-ELECTRIC CONVERSION WITH AMTEC RATHER THAN CONVENTIONAL THERMOELECTRIC CONVERTERS SHOULD PERMIT REDUCTION OF THE GPHS COMPLEMENT BY A FACTOR OF 3. THE ESTIMATED COST SAVINGS MAY APPROACH $40,000 PER ELECTRIC WATT LAUNCHED. AMTEC OPERATES WITH METALLIC SODIUM AS THE WORKING FLUID AND, UP TO NOW, ALL HIGH-TEMPERATURE, RECIRCULATING AMTEC SYSTEMS HAVE USED GRAVITY TO CARRY THE SODIUM FROM THE CONDENSER WALL TO A SUMP, WHERE AN ELECTROMAGNETIC PUMP RETURNS IT TO THE HIGH-TEMPERATURE ZONE. IN ZERO GRAVITY, WITH A CONVENTIONAL CONDENSER, THIS APPROACH FAILS BECAUSE THE SODIUM DISTRIBUTES ITSELF ON THE CONDENSER WALLS AND FAILS TO REACH THE PUMP INLET. FOR AMTEC SPACE OPERATION, OTHER MEANS OF SODIUM CONTROL AND CIRCULATION MUST, THEREFORE, BE DEVELOPED. THE APPROACHIN THIS PROJECT USES A WICK STRUCTURE TO COLLECT THE SODIUM CONTINUOUSLY AT THE CONDENSER AND DELIVER IT TO THE INLET OF AN ELECTROMAGNETIC PUMP. THE PUMP THEN RETURNS THE SODIUM TO THE HIGH-TEMPERATURE ZONE.