Flex Heat Pipe East-West Deployable Radiator

Lockheed Martin has developed a patented solution for increasing payload power on communications satellites which introduces a coupled East-West radiator assembly with deployable radiators. The deployable radiators are deployed in integration and test phases to provide equipment access. The equipment is mounted onto internal structural panels and is thermally coupled to both east and west radiators by flexible heat pipes which have dual condensers. Coupling to both east and west radiators provides greater average heat dissipation. This application is uniquely demanding for the flexible heat pipes due to heat transport, operating temperatures, pressure cycling and deployment cycling. This paper describes derivation of requirements for the flexible heat pipes for the radiator assembly, and qualification testing to verify that the heat pipe design will work as intended. A structural qualification unit was subjected to thermal cycling, pressure cycling, vibration, flex cycling and ultimately burst testing. The qualification unit was modified following burst test into a single condenser unit. It was then charged and subjected to thermal performance testing. The test results verify that the flexible heat pipe design meets all requirements for the East-West radiator assembly.