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A thermal control materials using a polyimide film named UPILEX-S™ is investigated concerning incident angle dependence of solar absorptance, temperature dependence of total hemispherical emittance, performances in flight and ground tests, and causes of degradation. The experiment indicated that the absorption coefficient increases at 0.44μm wavelength under protons and electrons radiation. The degradation seems to be caused by the generation of radicals.

New thermal control material named Smart Radiation Device (SRD) has been studied to apply for spacecraft. Infrared radiative properties of the SRD change depending on its own temperature without electrical or mechanical instruments. The SRD however shows too high solar absorptance to apply it as a radiator. To overcome such drawback, it is necessary to design and apply the mutilayer films on the SRD for reflecting solar radiation, keeping infrared radiative properties of the SRD. To perform optimum design of the multilayer films, the genetic algorithm (GA) was employed. In this paper, we propose a design of the thermal radiative properties of the SRD with the multilayer films.

A lightweight 100 W-class deployable radiator with environment-adaptive functions has been investigated. This radiator - Reversible Thermal Panel (RTP) - is composed of flexible high thermal conductive materials and a passive reversible actuator, and it changes its function from a radiator to a solar absorber by deploying/stowing the reversible fin upon changes in the heat dissipation and thermal environment. The RTP is considered one of the candidates of thermal control methodology for the Japanese Venus mission “Planet-C”, which will be launched in 2010 to save its survival heater power. In this paper, design and fabrication of the RTP proto-model (PM) and the test results of deployment/stowing characteristics in an atmospheric condition are reported. Thermal performance estimation with thermal analytical model of the RTP PM is also presented.

The MUSES-B spacecraft will be launched in 1996 by the Institute of Space and Astronautical Science (ISAS). Its primary mission is experiments on space Very Long Baseline Interferometry (VLBI) for radio astronomy using a large deployable antenna. A challenging thermal design must be compatible with a wide range of sun angle and an 86 minute eclipse. The thermal design and verification has been performed separately for the major modules of the spacecraft; a main structure, a deployable antenna and Reaction Control System (RCS). Special attention is paid to the exposed RCS whose solar input varies significantly depending on the sun angle. This paper describes the thermal design concept for MUSES-B and verification results of its thermal model test focusing on the main structure and the RCS.

The Smart Radiation Device (SRD) is a new thermal control material that decreases the temperature variation by changing the emissivity without using electrical instruments or mechanical parts. The emissivity of the SRD changes physically depending on its temperatures. Bonded only to the external surface of the spacecrafts, the SRD controls the temperature. The drawback of the SRD is the high solar absorptance. The multi-layer film for SRD was designed in order to decrease the solar absorptance from 0.81 to less than 0.2 by putting multi-layer film on it and the optical performance of the Smart Radiation Device with Multi-layer film (SRDM) was evaluated.

The Smart Radiation Device (SRD) is a new type of thermal control material for spacecraft. By changing its emissivity without using electrical instruments or mechanical parts, the SRD decreases the temperature variation of the applied place. The SRD changes its emissivity physically depending on its temperature. The drawback of the SRD is its high solar absorptance. In order to reduce the solar absorptance while keeping its emissivity variation, the wide band filter was designed for the SRD. The function of the wide band filter is to reflect sunlight and to transmit infrared light. The SRD with the wide band filter is called as the Smart Radiation Device with Multi-layer films (SRDM) and the target value of its solar absorptance is 0.13.