Thermal Subsystem Overview
The thermal control system is the method for controlling and monitoring the temperature of all hardware within the satellite. Based on the operational and non-operational temperature range specifications of each component, the thermal team designates an Allowable Flight Temperature (AFT) range that the thermal control system must regulate the temperature to. This allows the instruments and electronics boards to withstand the extreme thermal environment of space as the satellite transitions between different orbital conditions. To designate an appropriate AFT range, all components are regulated within a 15C - 20C margin from their datasheet (qualification) temperatures.
Designing the system requires that the team properly account for the power dissipation for each component, as well as the hardware’s material properties and the conductivity between one component and another.
The satellite is modeled in Thermal Desktop to classify the thermal profile of the spacecraft in different orbital conditions and design thermal control methods to maintain all hardware within its allowable flight temperature range. Thermal Desktop is organized by C&R Tech, which offers free, limited licenses for university projects that are in need of thermal modeling software.
While modeling allows the team to visualize the thermal profile, all models must be verified in the form of hand calculations to ensure that the software is indeed showing probable behavior. Hand calculations were performed in MATLab and Excel to verify all thermal models.
Thermal Desktop: https://www.crtech.com/products/thermal-desktop
Thermal Control Design
After much analysis and debate, the flight thermal control system was simplified to a single radiator panel, with the +x and +Y faces covered in thermal tape that was graciously donated to the student team by NASA Goddard.
The original thermal control design included copper straps to help regulate the temperature of the FLIR camera and ensure that the temperature of the camera would not introduce thermal effects into the images. This was de-scoped during the critical design phase of the project when it became apparent that the student team would be responsible for designing and validating the strap design themselves. Moving forward with thermal straps would have been met with significant time constraints, a lack of resources, and it would have created a high technical risk to the project. As a result, the thermal design was simplified, and the team will instead opt to restrict imaging operations during orbits with a high beta angle that would create poor imaging conditions.