The International Space Station (ISS) External Active Thermal Control System (EATCS)[1] maintains an equilibrium when the ISS environment or heat loads exceed the capabilities of the Passive Thermal Control System (PTCS). Note Elements of the PTCS are external surface materials, insulation such as Multi-Layer Insulation (MLI), or Heat Pipes. The EATCS provides heat rejection capabilities for all the U.S. pressurized modules, the Japanese Experiment Module (JEM), the Columbus Orbital Facility (COF), and the main power distribution electronics of the S0, S1 and P1 Trusses. The EATCS consists of two independent Loops (Loop A & Loop B), which both use mechanically pumped fluid state ammonia in closed-loop circuits. The EATCS is capable of rejecting up to 70 kW, and provides a substantial upgrade in heat rejection capacity from the 14 kW capability of the Early External Active Thermal Control System (EEATCS) via the Early Ammonia Servicer (EAS), which was launched on STS-105 and installed onto the P6 Truss.[1]
ISS External Active Thermal Control System (EATCS) diagram
Early Ammonia Servicer
DDCU cold plate design
There are two independent Loops (Loop A & Loop B) that combined make up the EATCS. The EATCS Loops perform three primary functions:
Heat Collection - Each Loop draws heat from five Heat Exchangers (HXs) mounted on the Destiny Laboratory, Node-2 & Node-3 as well as cold plates under three DC-to-DC Conversion Units (DDCUs) (one DDCU each on each Loop on the P1/S1 Trusses and two DDCUs each on each Loop on the S0 Truss) and two Main Bus Switching Units (MBSUs) on each Loop on the S0 Truss (see schematic below and Orbital Replacement Units (ORUs) for design of these units);
Heat Transportation - The Pump Module (PM) provides flow and accumulator functions and maintains proper temperature control at the pump outlet for each Loop. The PM consists of a single pump, a fixed charge accumulator, a Pump & Control Valve Package (PCVP) containing a firmware controller, startup heaters, isolation valves, and various sensors for monitoring performance. The Nitrogen Tank Assembly (NTA) controls the flow of ammonia out of the Ammonia Tank Assembly (ATA). The ATA contains two flexible, chambers incorporated into its ammonia tanks that expand as pressurized nitrogen from the NTA expels liquid ammonia out of the ATA. The major components in the ATA include two ammonia storage tanks, isolation valves, heaters, and various temperature, pressure, and quantity sensors;
Heat Rejection - Ammonia passes from the ATA through a two way path of the Flex Hose Rotary Coupler (FHRC) where heat captured while passing through the Heat Exchangers is directed to be expelled through the Heat Rejection System Radiators (HRSRs). The radiators are rotated by the Thermal Rotary Radiator Joint (TRRJ) which continually rotates the radiator wing for optimum cooling.
EATCS schematic overview
Pump Module (PM)
PM drawing
Nitrogen Tank Assembly (NTA)
NTA drawing (cover removed)
Ammonia Tank Assembly (ATA)
ATA drawing (cover removed)
Flex Hose Rotary Coupler (FHRC)
FHRC without MLI cover and in situ on the TRRJ
Heat Rejection System Radiator (HRSR)
HRSR drawing
EATCS components on the S1/P1 Trusses
TCS System of the ISS
References
^ ab"Active Thermal Control System (ATCS) Overview" (PDF). NASA.
external, active, thermal, control, system, international, space, station, eatcs, maintains, equilibrium, when, environment, heat, loads, exceed, capabilities, passive, thermal, control, system, ptcs, note, elements, ptcs, external, surface, materials, insulat. The International Space Station ISS External Active Thermal Control System EATCS 1 maintains an equilibrium when the ISS environment or heat loads exceed the capabilities of the Passive Thermal Control System PTCS Note Elements of the PTCS are external surface materials insulation such as Multi Layer Insulation MLI or Heat Pipes The EATCS provides heat rejection capabilities for all the U S pressurized modules the Japanese Experiment Module JEM the Columbus Orbital Facility COF and the main power distribution electronics of the S0 S1 and P1 Trusses The EATCS consists of two independent Loops Loop A amp Loop B which both use mechanically pumped fluid state ammonia in closed loop circuits The EATCS is capable of rejecting up to 70 kW and provides a substantial upgrade in heat rejection capacity from the 14 kW capability of the Early External Active Thermal Control System EEATCS via the Early Ammonia Servicer EAS which was launched on STS 105 and installed onto the P6 Truss 1 ISS External Active Thermal Control System EATCS diagram Early Ammonia Servicer DDCU cold plate design There are two independent Loops Loop A amp Loop B that combined make up the EATCS The EATCS Loops perform three primary functions Heat Collection Each Loop draws heat from five Heat Exchangers HXs mounted on the Destiny Laboratory Node 2 amp Node 3 as well as cold plates under three DC to DC Conversion Units DDCUs one DDCU each on each Loop on the P1 S1 Trusses and two DDCUs each on each Loop on the S0 Truss and two Main Bus Switching Units MBSUs on each Loop on the S0 Truss see schematic below and Orbital Replacement Units ORUs for design of these units Heat Transportation The Pump Module PM provides flow and accumulator functions and maintains proper temperature control at the pump outlet for each Loop The PM consists of a single pump a fixed charge accumulator a Pump amp Control Valve Package PCVP containing a firmware controller startup heaters isolation valves and various sensors for monitoring performance The Nitrogen Tank Assembly NTA controls the flow of ammonia out of the Ammonia Tank Assembly ATA The ATA contains two flexible chambers incorporated into its ammonia tanks that expand as pressurized nitrogen from the NTA expels liquid ammonia out of the ATA The major components in the ATA include two ammonia storage tanks isolation valves heaters and various temperature pressure and quantity sensors Heat Rejection Ammonia passes from the ATA through a two way path of the Flex Hose Rotary Coupler FHRC where heat captured while passing through the Heat Exchangers is directed to be expelled through the Heat Rejection System Radiators HRSRs The radiators are rotated by the Thermal Rotary Radiator Joint TRRJ which continually rotates the radiator wing for optimum cooling EATCS schematic overview Pump Module PM PM drawing Nitrogen Tank Assembly NTA NTA drawing cover removed Ammonia Tank Assembly ATA ATA drawing cover removed Flex Hose Rotary Coupler FHRC FHRC without MLI cover and in situ on the TRRJ Heat Rejection System Radiator HRSR HRSR drawingEATCS components on the S1 P1 Trusses TCS System of the ISSReferences Edit a b Active Thermal Control System ATCS Overview PDF NASA See also EditInternational Space Station ISS Integrated Truss Structure ITS Orbital Replacement Units ORUs Electrical system of the International Space Station Environmental Control and Life Support System ECLSS Integrated Cargo Carrier ICCs External Stowage Platform ESPs ExPRESS Logistics Carrier ELCs Scientific research on the ISS Retrieved from https en wikipedia org w index php title External Active Thermal Control System amp oldid 1086411499, wikipedia, wiki, book, books, library,
