2023 年度卒業論文「人工衛星の熱制御用途に向けた感温塗料の単層膜の特性と下地・膜厚による熱光学特性変化」
九州工業大学 工学部 宇宙システム工学科 機械宇宙システム工学コース
岩田研究室 学部 4 年 201A2002 秋山聡介
宇宙機はミッション期間中、日照・日陰による高温・低温環境といった熱的な環境に晒される。特に宇宙機の温度は、外部から宇宙機へと与えられる熱入力と、宇宙機から宇宙空間へと放出される熱出力の収支によって決定される。宇宙機の熱制御系は、宇宙機における熱の流路と量を調整することによって、搭載機器の温度を許容温度範囲内に収める必要がある。
熱制御を行う素子として、感温塗料を用いた受動型熱制御素子が提案されている。
感温塗料は塗料自身の温度に依存して吸収する光の波長と量が変化する材料のことであり、この特性を利用して宇宙機に入力する熱量及び宇宙機から出力される熱量を制御するということが狙いである。
特に本研究では、感温塗料単体の分光反射率及び分光透過率を測定し、感温塗料が有する光学特性を詳細に調査した。また、先行研究で用いられた供試体の構成及び測定結果を基に供試体の構成方法を変更し、熱光学特性（太陽光吸収率及び垂直放射率）を測定した。このことにより、素子を構成する層の種類が変更されることによる熱光学特性の変化量、また感温塗料の膜厚と熱光学特性の関係を明らかにした。
“Characteristics of monolayers of thermo-sensitive paints for thermal controlof satellites and variation of thermo-optical properties with substrate and filmthickness”
Spacecraft are exposed to thermal environments such as high and low temperatureenvironments due to sunlight and shade during the mission. In particular, thetemperature of a spacecraft is determined by the balance between the heat input
from the outside to the spacecraft and the heat output emitted from thespacecraft into space. The thermal control system of a spacecraft must keep thetemperature of onboard equipment within the allowable temperature range by
adjusting the heat flow path and amount in the spacecraft.
A passive thermal control element using temperature-sensitive paint has been
proposed as an element for thermal control. Thermosensitive paint is a material
that changes the wavelength and amount of light it absorbs depending on thetemperature of the paint itself, and its purpose is to control the amount ofheat input to and output from a spacecraft by utilizing this property.
In this study, the spectral reflectance and spectral transmittance of thethermosensitive paint alone were measured to investigate the optical propertiesof the thermosensitive paint in detail. In addition, the thermo-opticalproperties (solar absorption and vertical emissivity) were measured by changing
the method of constructing the EUT based on the composition and measurement
results of the EUT used in the previous study. By doing so, the amount of change
in thermo-optical properties due to changes in the type of layers used toconstruct the device and the relationship between the thickness of thethermosensitive paint and the thermo-optical properties were clarified.

目次
第 1 章 序論 ...........................................................................................................................4
1.1 研究背景......................................................................................................................41.2 研究動向......................................................................................................................5
1.2.1 SRD（Smart Radiation Device） ........................................................................5
1.2.2 EclipseVED(Eclipse variable-emissivity device) .........................................9
1.2.3 先行研究(6) .........................................................................................................10
1.3 研究目的....................................................................................................................17
第 2 章 基礎理論 ..................................................................................................................19
2.1 熱環境 .......................................................................................................................19
2.2 基礎的な光学 ............................................................................................................192.2.1 反射・吸収・透過 ..............................................................................................20
2.2.2 放射率 ................................................................................................................202.2.3 キルヒホッフの法則 ..........................................................................................212.2.4 プランクの法則 .................................................................................................212.3 熱光学特性 ................................................................................................................212.3.1 太陽光吸収率 .....................................................................................................222.3.2 全半球放射率・垂直放射率 ...............................................................................22
第 3 章 研究手法 ..................................................................................................................24
3.1 実験装置....................................................................................................................243.1.1 熱電対データロガー ..........................................................................................24
3.1.2 真空計 ................................................................................................................24
3.1.3 定温乾燥器 .........................................................................................................26

3.1.4 真空冷却装置 .....................................................................................................26
3.1.5 分光光度計 .........................................................................................................29
3.2 真空冷却装置の改良 .................................................................................................31
第 4 章 塗装膜単体の特性 ...................................................................................................36
4.1 供試体 .......................................................................................................................364.2 測定手法....................................................................................................................374.2.1 光学特性の測定 .................................................................................................374.3 実験結果....................................................................................................................374.4 考察 ...........................................................................................................................44
第 5 章 下地の変更による熱光学特性の変化 ......................................................................47
5.1 供試体 .......................................................................................................................475.2 測定手法....................................................................................................................485.2.1 光学特性の測定 .................................................................................................48
5.2.2 感温塗料の加熱 .................................................................................................485.3 実験結果....................................................................................................................495.4 考察 ...........................................................................................................................53
第 6 章 膜厚変更による熱光学特性の変化 ..........................................................................56
6.1 供試体 .......................................................................................................................56
6.2 測定手法....................................................................................................................57
6.2.1 光学特性の測定 .................................................................................................57
6.2.2 感温塗料の加熱 .................................................................................................57
6.3 実験結果....................................................................................................................58
6.4 考察 ...........................................................................................................................66
第 6 章 結論 .........................................................................................................................68
第 7 章 今後の課題 ..............................................................................................................68
参考文献 ................................................................................................................................69
謝辞 ........................................................................................................................................71
付録 ........................................................................................................................................72

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