ISS Thermal Management

The Heat Pipe Radiator Systems for Starboard 0 truss segment of the International Space Station (SOHPRS) was developed under contract to Boeing Space Systems. Thermal Management provided complete component and system level design, analysis, and testing. In addition to the flight system, a structural risk mitigation 21' x 5' radiator, qualification heat pipe plates, and transfer heat pipes were also supplied and tested. Additional flight hardware included two different machined plate heat pipe radiators for other electronics modules.

The purpose of this radiator system is the rejection of heat from seven electronics modules located in the center segment of the ISS truss structure. The system consists of one central heat pipe radiator, fourteen transport pipes, and seven equipment plates, each a machined aluminum plate structure with four or six heat pipes. The plates provide ORU-EVA interfaces (orbital replacement unit interfaces for the electronics modules so astronauts can replace them while space walking). The transport heat pipes (as 7 pairs) are 1.3" OD and 20 to 24 feet long.

The central heat pipe radiator is 21' long x 5' wide with 54 embedded heat pipes including 12 header heat pipes, each of which is 21' long. A two-tiered heat pipe network is embedded in aluminum honeycomb construction. Thermal coatings are Z-93 white paint and silver Teflon tape.

The use of qualified make-break thermal interfaces between the electronics module, the heat pipe plates, the transfer heat pipes, and the central radiator significantly eased integration of this large system by Boeing to the S0 truss structure.

Another major development was the Zenith and Nadir facing Heat Pipe Radiator Systems for Payload Mating Adaptor-1 (PMA-1) of the International Space Station (PMA-1 HPRS) for Boeing Space Systems. The group provided complete component and system level design, analysis, and testing. The group was awarded the Exceptional Supplier of the Year award by the Boeing Space Flight Awareness program recognizing the outstanding performance in the advancement of mission safety and success for human space flight programs.

The purpose of this system is the rejection of heat from two electronics modules located outside of PMA-1. One of the radiators has a view toward the Earth and the other toward space. Each radiator assembly consisted of four machined aluminum plates assembled into an open box configuration with bonded spreader heat pipes. Each assembly provides an ORU-EVA interface for the electronics module. Three of the four plates in each assembly are coated with OSR mirror tiles for radiation heat rejection.

Additional heat pipe radiators for the ISS include the DC-to-DC Converter Unit (DDCW) radiators cooling power conversion electronics on the Z=1 truss.

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