## 4 On-Orbit Thermal Analysis of S-STEP
### Overview of Thermal Analysis
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multicolumn{2}{c}{**Conductivity**} & \multirow{2}{*}{**Density (kg/m\({}^{3}\))**} & \multicolumn{2}{c}{**Specific Heat**} & \multirow{2}{*}{**Remark**} \\  & **(W/m/K)** & & & & \\ \hline Al-6061 & 170 & 2768 & 879.2 & \begin{tabular}{c} Unit, radiator, \\ brackets \\ \end{tabular} \\ \hline Al-7075 & 121.2 & 2770 & 961.2 & \begin{tabular}{c} Honeycomb panel \\ (Facesheet) \\ \end{tabular} \\ \hline CFRP & 30 & 1910 & 711.76 & Solar panel \\ \hline \multirow{3}{*}{Graphite sheet} & \(k_{X}=1200\) & \multirow{3}{*}{1200} & \multirow{3}{*}{1200} & \multirow{3}{*}{1200} & Graphite sheet, 15 \\  & \(k_{Z}=5\) & & & layers stacked [25] \\ \hline \multirow{3}{*}{Honeycomb core} & \(k_{X}=3.25\) & \multirow{3}{*}{129.75} & \multirow{3}{*}{921.6} & Honeycomb panel \\  & \(k_{Y}=2.17\) & & & (Core) \\ \hline Foil radiator & 0 & 300 & 1200 & Foil radiator \\ \hline \multirow{3}{*}{\begin{tabular}{c} Kevlar \\ honeycomb \\ \end{tabular} } & 0.40 & 96 & 1420 & \
\begin{tabular}{c} SAR antenna \\ radiating board \\ \end{tabular} \\ \hline RF-35A2 & 0.29 & 2280 & 990 &
\begin{tabular}{c} SAR antenna \\ radiating board \\ \end{tabular} \\ \hline Sun shield & 1000 & 206 & 1200 & Sun shield \\ \hline MLI & 0 & 300 & 1200 & MLI \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Thermo-physical properties used for thermal analysis. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multicolumn{2}{c}{**Absorptivity**} & \multirow{2}{*}{**Emissivity**} & \multirow{2}{*}{**\(\alpha\)/\(\epsilon\)**} & \multirow{2}{*}{**Remark**} \\  & **[\(\alpha\)]** & & & \\ \hline Alodine & 0.35 & 0.07 & 5.00 & Radiator, structural brackets \\ \hline \multirow{3}{*}{Black anodizing} & \multirow{3}{*}{0.88} & \multirow{3}{*}{0.88} & \multirow{3}{*}{1.00} & Honeycomb facesheet, \\  & & & & battery mounting I/F plate, \\  & & & & foil radiator (Inside) \\ \hline Kapton & 0.35 & 0.40 & 0.88 & Honeycomb core (Edge) \\ \hline Gold coating & 0.23 & 0.05 & 4.60 & TRM (SAR ant. side) \\ \hline Graphite sheet & 0.66 & 0.30 & 2.20 & Graphite sheet \\ \hline MLI & 0.05 & 0.05 & 1.00 & MLI, electronic units \\ \hline \multirow{3}{*}{OSR} & \(\begin{array}{c}0.11\text{ (BOL)}\\ 0.24\text{ (EOL)}\end{array}\) & \multirow{3}{*}{0.80} & \(\begin{array}{c}0.14\text{ (BOL)}\\ 0.30\text{ (EOL)}\end{array}\) & \multirow{3}{*}{Radiator} \\ \hline PTFE & 0.12 & 0.85 & 0.14 & SAR antenna (+\(z\)-axis) \\ \hline Solar cell & 0.61 & 0.83 & 0.90 & Solar panel \\ \hline \multirow{3}{*}{Sun shield} & \(\begin{array}{c}0.46\\ /0.56\text{ (EOL)}\end{array}\) & \multirow{3}{*}{0.69} & \(\begin{array}{c}0.62\text{ (BOL)}\\ 0.81\text{ (EOL)}\end{array}\) & \multirow{3}{*}{Sun shield (Outside)} \\  & \(\begin{array}{c}0.43\text{ (BOL)}\end{array}\) & \multirow{3}{*}{0.72} & \(\begin{array}{c}0.15\text{ (BOL)}\\ 0.35\text{ (EOL)}\end{array}\) & \multirow{3}{*}{
\begin{tabular}{c} Foil radiator, bottom side of \\ electronic units (+\(z\)-axis), \\ solar panel \\ \end{tabular} \\ \hline Antenna & 0.25 & 0.75 & 0.33 & GPS ant., ISL ant., S-band ant. \\ \hline VDA & 0.065 & 0.023 & 2.83 & GPS ant., ISL ant., S-band ant. \\ \hline Al-VDA & 0.09 & 0.028 & 3.214 & Honeycomb panel (Local) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Thermo-optical properties used for thermal analysis.