The Thermal Control System’s goal is to protect AcubeSAT and its payload from the harsh space environment such as the Sun’s, IR and Albedo radiation. While the operational temperature range for each internal component varies, the subsystem needs to find a thermal control plan that would satisfy every subsystem’s needs.
Some temperature ranges for our CubeSat’s most crucial components are:
1. The microfluidics chip, where the scientific experiment is going to take place would need to have a temperature of 30±2°C.
2. CubeSat’s battery has an operational mode temperature range of 0–45°C, while if in a non-operational mode a range of -5–50°C.
3. Most electronical components, such as PCBs, will have an operational mode temperature range of -40–85°C and a non-operational of -50–85°C.
Passive and Active Thermal Control
To successfully accomplish these temperature ranges a thermal control plan was made for each crucial component. Firstly, a heater will be attached under the microfluidics chip. A black coating, with high emissivity and high absorptivity, will also be added on the interior of the vessel. This will prevent the heat from leaving the vessel. Adding to that, a structural plastic, Ultem, shall be placed on the internal conductive interfaces of the vessel, reducing the heat outcome via conduction. As for the battery, a polymide insulated heater will be in contact with the battery. Concerning the PCBs, their operational mode temperature range, being that wide, will be achieved with no extra thermal insulation.
Thermal Analyses and Test Results
For a final decision to be made, concerning AcubeSAT’s thermal control, thermal analyses need to take place. The software the subsystem is using for its thermal analyses is Ansys Workbench.In this software,the extreme environmental cases of the nanosatellite are being examined . These extreme cases include the hot case, in which most of the components are in operation, while Solar, IR and Albedo radiation have a maximum magnitude, and the cold case, having a minimum internal heat dissipation and minimum radiation values. These analyses provide the Thermal subsystem with the actual, not the required ones, temperature ranges of the components, with and without the applied passive and active thermal insulations. Comparing these two cases of temperature ranges, the actual and the required, we can decide on the final thermal control of AcubeSAT. Last but not least, some practical thermal tests are necessary inside a thermal vacuum chamber, verifying the thermal analysis results by minimizing the uncertainties that occured.