Thermal
The Thermal module allows Sedaro to simulate component temperatures, thermal interface heat flow, surface solar absorption and thermal emission, and temperature controller behavior throughout the simulation. To simulate the agent's thermal performance accurately, you must assign temperature limits and a thermal capacitance to each component. Then, you must define the size and conductivity of thermal interfaces between components.
Enable Module
To run the Thermal subsystem on your agent in a scenario, you must enable the Thermal module by clicking the module toggle.
Enable the thermal module
Temperature Controllers
Temperature controllers are used to actively heat or cool components. They are particularly useful for ensuring that the temperatures of battery packs and sensitive payload components remain within a given temperature range. Heaters require a thermal sink into which they dump their generated heat, while coolers require a thermal sink to dump heat and also a thermal source to cool.
Create a temperature controller
Add the following temperature controllers:
| Temperature Controller Name | Power Source | Temperature Controller Type | Rate (W) | Controlled Component |
|---|---|---|---|---|
| Battery Heater A | Power Processor | Heater | 58 | Battery Pack A |
| Battery Heater B | Power Processor | Heater | 58 | Battery Pack B |
| Payload Cooler | Power Processor | Cooler | 40 (80% efficiency) | Payload Camera |
After you have created the temperature controllers, you must add control states to each controller. These function as conditions that determine when the temperature controller should be active. Each control state requires a temperature goal and operational modes during which it should be able to function.
Create a temperature control state
Add the following temperature control states to the temperature controllers:
| Control State Name | Controller | Constant Temperature | Operational Modes |
|---|---|---|---|
| Nominal Heat | Battery Heater A | 25°C | All |
| Nominal Heat | Battery Heater B | 25°C | All |
| Nominal Temperature | Payload Cooler | -10°C | Imaging, Standby |
Thermal Interface Materials
Thermal Interface Materials (TIMs) are the materials used to make thermal connections between components. Their attributes determine how much heat is transferred through a thermal interface given an interface area and temperature difference. In some cases, greater thermal conductivity between components is desired. In other cases, less thermal conductivity—and therefore greater thermal resistivity—is preferable.
Define a Thermal Interface Material
Define the following TIMs:
| Thermal Interface Material Name | Resistivity (K·m/w) | Thickness (m) | Hot Temperature Rating (°C) | Cold Temperature Rating (°C) |
|---|---|---|---|---|
| Gap Pad | 0.2 | 0.003 | 200 | -60 |
| Mount | 0.05 | 0.01 | 100 | -40 |
| Isolator | 1 | 0.03 | 100 | -40 |
Thermal Interfaces
Here you use the map of the agent's components to define the thermal interfaces between them. To create a thermal interface, click on the small dark circle at the bottom of a component and drag it to another component. After you release, a thermal interface menu will appear where you can choose the thermal interface material and area for the thermal interface. You can optionally choose not to assign a TIM or interface area.
Create a thermal interface
Unlike other components, surfaces do not take a TIM or interface area but still require a thermal interface to be connected.
It does not matter on which side of the thermal interface a component is connected; it will function the same.
You can use the checkboxes in the table below to keep track of which thermal interfaces you have added. Define thermal interfaces similar to the following:
| Side A | Side B | Thermal Interface Material | Area (m2) | | :------------------------: | :------------------------------: | :------------------------: | :------------------: | ------------------------- | | Spacecraft Chassis | Communication Chassis | | | | | Spacecraft Chassis | Control Chassis | | | | | Spacecraft Chassis | Fuel Tank | | | | | Spacecraft Chassis | Payload Chassis | | | | | Spacecraft Chassis | Power Chassis | | | | | Spacecraft Chassis | Thruster | | | | | Spacecraft Chassis | +X Surface | | | | | Spacecraft Chassis | +Y Surface | | | | | Spacecraft Chassis | -Y Surface | | | | | Spacecraft Chassis | +Z Surface | | | | | Spacecraft Chassis | -Z Surface | | | | | Spacecraft Chassis | +Y Fixed Solar Panel | Mount | 0.05 | | | Spacecraft Chassis | +Y Fixed Solar Panel | Mount | 0.05 | | | Spacecraft Chassis | +Y Sun Track Solar Panel | Mount | 0.05 | | | Spacecraft Chassis | +Y Sun Track Solar Panel | Mount | 0.05 | | | +Y Fixed Solar Panel | Solar Panel +Y Fixed Surface | | | | | -Y Fixed Solar Panel | Solar Panel -Y Fixed Surface | | | | | +Y Sun Track Solar Panel | Solar Panel +Y Sun Track Surface | | | | | +Y Sun Track Solar Panel | Solar Panel +Y Sun Track Back | | | | | -Y Sun Track Solar Panel | Solar Panel -Y Sun Track Surface | | | | | -Y Sun Track Solar Panel | Solar Panel -Y Sun Track Back | | | | | Communication Chassis | Crosslink Antenna | Mount | 0.01 | | | Communication Chassis | Crosslink Modem | Gap Pad | 0.01 | | | Control Chassis | Flight Computer | Gap Pad | 0.03 | | | Control Chassis | GPS | Gap Pad | 0.02 | | | Control Chassis | Gyro | Gap Pad | 0.01 | | | Control Chassis | Magnetometer | Gap Pad | 0.01 | | | Control Chassis | MT-X | Gap Pad | 0.05 | | | Control Chassis | MT-Y | Gap Pad | 0.05 | | | Control Chassis | MT-Z | Gap Pad | 0.05 | | | Control Chassis | RW-X | Gap Pad | 0.05 | | | Control Chassis | RW-Y | Gap Pad | 0.05 | | | Control Chassis | RW-Z | Gap Pad | 0.05 | | | Control Chassis | Star Tracker | Gap Pad | 0.03 | | | Payload Chassis | Payload Camera | Isolator | 0.05 | | | Payload Chassis | Payload Computer | Gap Pad | 0.03 | | | Payload Cooler (Regulated) | Payload Camera | | | | | Payload Cooler (Sink) | -X Surface | | | | | Power Chassis | Power Processor | Gap Pad | 0.05 | | | Power Chassis | Battery Pack A | Gap Pad | 0.1 | | | Power Chassis | Battery Pack B | Gap Pad | 0.1 | | | Battery Pack A | Battery Heater A | | | | | Battery Pack B | Battery Heater B | | | |
Thermal Ratings & Capacitance
Each component, surface, and thermal interface has a hot temperature rating and a cold temperature rating. These ratings are used for analytical purposes to determine whether a component is operating within its temperature limits, but they are not enforced in the simulation.
Each component (except surfaces) within an agent has a thermal capacitance, with the default thermal capacitance being 1000 J/K. The thermal capacitance determines how much heat is required to raise or lower the component's temperature by 1°C or 1 K.
You can use the checkboxes in the table below to keep track of which temperature ratings and thermal capacitances you have modified. Open the Spacecraft menu by clicking on the icon or pressing S. Then, set the temperature ratings and thermal capacitance of each component to be similar to the following:
| Subsystem | Component Name | Hot Temperature Rating (°C) | Cold Temperature Rating (°C) | Thermal Capacitance (J/K) | | :---------------: | :----------------------: | :-----------------------------: | :------------------------------: | :-----------------------: | ------------------------- | | Power | Power Processor | 100 | -40 | 3000 | | | Power | Battery Pack A | 100 | -40 | 10000 | | | Power | Battery Pack B | 100 | -40 | 10000 | | | Power | +Y Sun Track Solar Panel | 100 | -40 | 3000 | | | Power | -Y Sun Track Solar Panel | 100 | -40 | 3000 | | | Power | +Y Fixed Solar Panel | 100 | -40 | 1000 | | | Power | -Y Fixed Solar Panel | 100 | -40 | 1000 | | | Command & Control | Flight Computer | 85 | -45 | 100 | | | Data Handling | Downlink Modem | 100 | -40 | 1000 | | | Data Handling | Downlink Antenna | 100 | -40 | 1000 | | | GNC | GPS | 60 | -10 | 500 | | | GNC | Star Tracker | 50 | -20 | 800 | | | GNC | Magnetometer | 85 | -55 | 200 | | | GNC | Gyro | 80 | -40 | 300 | | | GNC | MT-X | 100 | -40 | 1000 | | | GNC | MT-Y | 100 | -40 | 1000 | | | GNC | MT-Z | 100 | -40 | 1000 | | | GNC | RW-X | 60 | -20 | 3500 | | | GNC | RW-Y | 60 | -20 | 3500 | | | GNC | RW-Z | 60 | -20 | 3500 | | | GNC | Fuel Tank | 100 | -40 | 10000 | | | GNC | Thruster | 100 | -40 | 1000 | | | Thermal | Payload Cooler | 100 | -40 | 3000 | | | Thermal | Battery Heater A | 100 | -50 | 1000 | | | Thermal | Battery Heater B | 100 | -50 | 1000 | | | Structure | Spacecraft Chassis | 100 | -40 | 30000 | | | Structure | Control Chassis | 100 | -40 | 10000 | | | Structure | Power Chassis | 100 | -40 | 5000 | | | Structure | Communication Chassis | 100 | -40 | 3000 | | | Payload | Payload Chassis | 100 | -80 | 10000 | | | Payload | Payload Computer | 85 | -45 | 150 | | | Payload | Payload Camera | 60 | -60 | 5000 | |