# Quasi-All-Passive Thermal Control System Design and On-Orbit Validation of Luojia 1-01 Satellite
## 6 Analysis of in-Orbit Performance and Modeling Modification
### On-Orbit Data Analysis  
The temperature variation curve of inside instruments of the satellite is shown in Figure 15. Among them, owing to the imaging tasks and data transmission tasks at the 37 th orbit and 50 th orbit, the temperature of the focal plane unit and OBDH is increasing apparently. The temperature of focal the plane unit is as high as 23.4 \({}^{\circ}\)C and the OBDH is at 22.7 \({}^{\circ}\)C. The temperatures of the camera and battery is stable under control and temperature fluctuation is better than 2 \({}^{\circ}\)C when the camera is not imaging. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Subject**} & \multirow{2}{*}{**Heating Circuit**} & \multirow{2}{*}{**Assigned Power (W)**} & \multirow{2}{*}{**Duty Cycle**} & \multicolumn{2}{c}{**Actual Power**} \\  & & & & **High Temp** & **Low Temp** \\ \hline
1 & Camera-1 & H1 & 2 & 0.34 & 0.70 & 0.68 & 1.4 \\
2 & Camera-2 & H2 & 2 & 0 & 0 & 0 & 0 \\
3 & Battery-1 & HS & 2 & 0.30 & 0.66 & 0.60 & 1.32 \\
4 & Battery-2 & H6 & 2 & 0 & 0 & 0 & 0 \\  & & & sum & & 1.28 & 2.72 \\ \hline \hline \end{tabular}
\end{table} 
Table 14: The duty cycle and power consumption of the heating regions. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Theroscope**} & \multirow{2}{*}{**Subject**} & \multirow{2}{*}{**High Temp**} & \multirow{2}{*}{**Low Temp**} \\  & & & & **Condition (\({}^{\circ}\)C)** & & **Condition (\({}^{\circ}\)C)** \\ \hline
1 & T1 (Thermistor) & Camera-1 & 12.4 & 11.9 \\
2 & T2 (Thermistor) & Camera-2 & 13.9 & 10.8 \\
3 & T3 (Thermistor) & Focal plane unit & 24.9 & 7.7 \\
4 & T4 (Thermistor) & OBDH & 26.7 & 6.1 \\
5 & T5 (Thermistor) & Battery-1 & 19.9 & 18.2 \\
6 & T6 (Thermistor) & Battery-2 & 20.6 & 18.4 \\
7 & T7 (Thermistor) & Reaction wheel I & 28.0 & 8.3 \\
8 & T8 (Thermistor) & Star tracker A & 18.4 & \(-0.5\) \\
9 & T9 (Thermistor) & Star tracker B & 20.3 & 0.3 \\
10 & T1 (thermocouple) & Camera holder & 13.5 & 9.0 \\
11 & T2 (thermocouple) & Reaction wheel II & 20.7 & 4.3 \\
12 & TC3 (thermocouple) & Navigation unit & 29.3 & 5.5 \\
13 & TC4 (thermocouple) & Signal processing unit & 21.4 & 5.2 \\
14 & TC5 (thermocouple) & Magnetometer & 15.3 & 2.6 \\
15 & TC6 (thermocouple) & MEMS gyroscope & 20.3 & 7.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Temperatures of the onboard instruments in thermal balance test. The temperature variation curve of outside instruments of the satellite is shown in Figure 16. Star tracker A is stable in the range from 11.8 \({}^{\circ}\)C to 13.0 \({}^{\circ}\)C. Star tracker B is stable in the range from 11.6 \({}^{\circ}\)C to 14.5 \({}^{\circ}\)C. The MEMS gyroscope is stable in the range from 14.7 \({}^{\circ}\)C to 17.5 \({}^{\circ}\)C. The digital Sun sensor is stable in the range from 10.0 \({}^{\circ}\)C to 22.0 \({}^{\circ}\)C. The magnetometer is stable in the range from 15.5 \({}^{\circ}\)C to 18.4 \({}^{\circ}\)C. Temperature fluctuations are in line with expectations. Figure 16: Temperature variation curve of the outside instruments in the Luojia 1-01. Figure 15: Temperature variation curve of the inside instruments on the Luojia 1-01. Taking all data from the in-orbit balanced status, ground thermal tests and thermal analysis into consideration, the model needs to be improved and updated. The comparison data is shown in Table 15.  
It can be seen from Table 15 that the temperature of each measuring point in-orbit has a margin of less than 8 \({}^{\circ}\)C compared to the high temperature conditions in the test, and a margin of less than 15 \({}^{\circ}\)C compared to the low temperature conditions in the test. All temperatures of in-orbit instruments fall in between the high and low temperature condition results. It indicates the TCS design is valid and the results of the ground thermal balance tests and thermal analysis are correct and within tolerance.