Thermal

Overview 

This page and its subpages contain thermal system designs that are particular to ArcticSat. Please refer to General Bus Design - Thermal for general thermal information. Please open the tree item for more detailed design and analysis results.

Thermal Block Diagrams

As of July 24th, we do not know for sure if radiators are needed for ArcticSat.

Figure 2: ArcticSat System Block Diagram

Figure 3: Thermal Control Block Diagram

Preliminary Thermal Design

Thermistors

Thermistors will be placed to monitor the temperatures of the

• CDH computer

• ADCS board

• Batteries

• Reaction wheel

• Payload

• Power board

• Communications equipment

• Solar arrays

Except for those on the batteries, these thermistors will only be used for telemetry and health monitoring, as none of these components will have active thermal controls. All thermistors used will be automotive grade to improve reliability and lifetime. Board-mounted thermistors will be soldered, while component-mounted ones will be bonded on. A diagram of the thermal control system, including the thermistors, heaters, and flows of data and heat can be found in Figure 3.

Batteries and Heaters

ArcticSat's batteries may require heating to stay alive, depending on the impacts of the short eclipses and temperature ranges expected during launch. Analysis has not yet included eclipses, and a launch provider has not yet been selected. The Datec heaters from Iris's design are included on ArcticSat as they are very low mass and volume. These 3D printed heaters were developed by Datec Coating Corporation in Ontario, and qualified on Iris. Thermistors on the battery will inform CDH of temperatures, and CDH will turn heaters on/off. The heater will be secured using thermal epoxy.

Structure and Layout

ArcticSat has an aluminum shell structure which allows for fairly low resistance heat conduction about the satellite. Two specific areas of concern for the thermal subsystem are the batteries and the payload electronics. As mentioned above, the batteries have an electric heater, but they will also generate heat while in use. Both of these attributes will cause local temperatures to fluctuate. The payload electronics must be kept at a constant, pre-calibrated temperature. Because of this, the batteries and the payload electronics are placed far apart in the bus layout. 

While Iris's structure was black anodized for thermal performance, little difference was seens between black and clear anodization in analyses for ArcticSat. As such, and pending more detailed analysis, this CubeSat will use clear anodization to improve its optical visibility. The solar arrays have high surface area to volume ratio, and could quickly exceed their temperature limits while constantly being exposed to the Sun. These arrays may require highly reflective paints on the front, or radiative coatings on the back to manage temperatures properly. More detailed analysis is required to determine this.