## 3 On Orbit Operations and Anomaly Analysis
### Thermal Performance  
Figure 21 shows the temperature ranges of the various IDEASSat subsystems during on-orbit operations (light blue bars) compared to their respective operational temperature ranges (orange bars), as well as those measured during thermal vacuum testing (dark blue bars), and values predicted using the Thermal Desktop analysis software (green bars). From top to bottom, the subsystems shown include the battery module, the body mounted (PV0) and deployable solar panels (PV1 and PV2), the UHF transceiver, the EPS controller board, the CDH OBC, as well as the ADCS inertial measurement unit (IMU), star tracker (Track), and exterior. Figure 20: Command reject count in IDEASSat flight data. It can be seen that the on-orbit temperature ranges all fell within the operational limits, indicating that good thermal margins were achieved. It can also be seen that the actual on-orbit temperatures generally trended higher than those predicted by the thermal analysis and encountered during thermal vacuum testing. In the case of the solar panels, the discrepancy between thermal vacuum and on-orbit temperatures is not surprising, given that the panels were not illuminated in the thermal vacuum chamber, or subject to extreme radiation to cold space. In the case of the EPS, CDH, ADCS IMU, and the battery module however, this suggests that the heat dissipation of these subsystems on orbit may have been higher than in the thermal vacuum testing or assumed during thermal analysis, potentially due to differences in operating state. The relatively small on-orbit temperature ranges of the UHF transceiver and the battery module are worth mentioning, given the unique operating conditions and constraints of these two locations. The UHF transceiver was subject to a relatively high level of power dissipation due to regular beaconing every 30 s. The UHF transceiver was therefore attached directly to the inside of the spacecraft chassis, allowing the chassis to serve as a  
Figure 21: The temperature range of the satellite subsystems. Orange: operating limit temperature; green: environmental test temperature range; dark blue: thermal analysis temperature prediction; light blue: actual on-orbit ambient temperature. Temperatures shown from top to bottom are for: EPS battery module (Battery), solar panels (PV) including body mounted panel (PV0) and deployable panels (PV1 and PV2), UHF transceiver (UHF), electrical power subsystem (EPS), command and data handling (CDH), ADCS inertial measurement unit (IMU), star tracker (Track), and exterior (External). heat sink for the transceiver, which proved to be effective in constraining the transceiver on-orbit temperatures to relatively benign values. The lithium-ion battery module had one of the narrowest operational temperature ranges of the entire spacecraft. As such, the battery cells were kept relatively thermally isolated from the rest of the spacecraft, with the main thermal interface being the electrical connector and the standoffs connecting the module to the EPS controller board. Although the on-orbit temperature range of the batteries was slightly higher than predicted using Thermal Desktop, the range of values was nonetheless relatively constrained and well within the operational limit, as well as that predicted during thermal vacuum testing. The on-orbit temperature ranges of the solar panels are worth exploring in more detail. Since the body-mounted solar panel (PV0) was located on the same face as the ADCS coarse sun sensor, it can be assumed to have been directly pointed at the Sun during sunlit segments of the spacecraft orbit. Although the average temperature of PV0 was predicted to be higher than that of the two deployable panels (PV1, and PV2) in thermal analysis, it can be seen from Figure 21 that the temperature discrepancy between the body mounted and deployable panels was significantly higher in on orbit data compared to in thermal analysis. Figure 22 shows the temperature variation of three solar panels during the on-orbit operations.