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This paper presents thermal-vacuum test data obtained for the JEM MAXI loop heat pipe (LHP) with two separate radiators operating under transient regimes representative of those to be encountered during the flight. The Monitor of All-sky X-ray Image (MAXI) in the Japanese Experiment Module (JEM), on the International Space Station (ISS), is an X-ray camera with wide fields of view to monitor the universe. The LHP collects about 32 Watts of heat dissipated by the detector and thermoelectrics and transports it to two separate radiators, with orthogonal views to space. Propylene is used as a working fluid due to a wide useful operating temperature range from -60°C to +60°C needed for this program. The LHP utilizes two fluid flow regulators to control fluid flow in the two parallel condensers and is equipped with two startup heaters, and three shutdown heaters controlled by six thermostats.

This paper experimentally and analytically evaluates the heat rejection/retention performance of a reversible thermal panel (RTP) which can autonomously change thermal performance depending on its own thermal conditions. The RTP is considered as a candidate methodology for thermal control of Venus mission, PLANET-C, in order to save survival heater power. An RTP prototype was tested and evaluated. An analytical thermal model of the RTP was also developed, and basic performances of the RTP were evaluated. Thermal performance of the RTP when applied to the longwave camera (LIR) of the PLANET-C was evaluated with an analytical thermal model as functions of fin deployment directions and rear surface properties of the RTP's fin. The analytical results showed that the RTP can save heater power in comparison to a conventional radiator.

A Reservoir Embedded Loop Heat Pipe (RELHP) has a liquid reservoir, located in the evaporator, to ease start-up of the LHP. The RELHP is used for heat transfer from the experimental heat load to a deployable radiator (DPR) on the Engineering Test Satellite-VIII (Kiku-8). This DPR is one of the experimental apparatus on the Kiku-8. The RELHP in the DPR has an evaporator, a condenser, transport lines to circulate a fluid and it utilizes the evaporation and condensation of the working fluid to transfer heat. The DPR on the Engineering Test Satellite-VIII (Kiku-8) was launched into a geo stationary orbit by a H-IIA rocket on Dec. 18, 2006. The DPR radiator was deployed successfully and the first start-up of the RELHP in an orbital environment was conducted smoothly. This paper describes the characteristics of the DPR and the RELHP on Kiku-8 in an orbital environment in the first year.