Spacecraft
The spacecraft menu is where you will define spacecraft-wide entities and components.
Open the spacecraft menu by clicking the icon in the navigation panel or by pressing the S key.
Open the spacecraft menu
CAD Model
The agent's CAD model can be chosen by uploading a locally stored CAD model (.glb file) or by selecting one of the included models. By default, the branch will have the Wildfire model already selected, but you can change this if you would like. The CAD model is helpful for visualizing the position and orientation of the spacecraft when viewing scenario results, but the model itself does not affect any values or calculations during the simulation.
Reference Vectors
Reference vectors are vectors that are not fixed within the spacecraft's inertial body frame and may move throughout a simulation. There are three main types of reference vectors:
- Celestial: vectors pointing to celestial objects like the Sun and Moon
- Local: vectors pointing to spacecraft-local concepts like reference frame vectors or pointing directions
- Targets/Target Groups: vectors pointing to individual targets or the active agent within a target group
Create a reference vector
Celestial Reference Vectors
Create the following celestial reference vector:
| Reference Vector Type | Representation used by algorithms | Local Vector Direction |
|---|---|---|
| Celestial | Estimate | Sun |
Local Reference Vectors
Create the following local reference vectors:
| Reference Vector Type | Representation used by algorithms | Local Vector Direction |
|---|---|---|
| Local | Estimate | Nadir |
| Local | Estimate | Ram |
| Local | Estimate | Magnetic Field |
Target Group Reference Vectors
Create the following target group reference vectors:
| Reference Vector Type | Representation used by algorithms | Target Group |
|---|---|---|
| Target Group | Estimate | Wildfires |
| Target Group | Estimate | LaserComm Relays |
Geometry
Body Frame Vectors
Body frame vectors are vectors that will remain fixed in the spacecraft's body frame throughout a simulation. They are used to describe pointing alignment and the orientation of an agent's components. They can be defined with spherical angles or vector coordinates.
On a new spacecraft branch you will already see 6 body frame vectors because when the branch is initialized, the principal (positive and negative X, Y, and Z) axes are automatically added to the agent.
Create a body frame vector
Define the following body frame vector using spherical angles:
| Body Frame Vector Name | Angle θ | Angle φ |
|---|---|---|
| Crosslink Boresight | 90° | 0° |
External Surfaces
External surfaces are used to model some types of orbital perturbations and are also used as thermal sources and radiators. Surfaces can be fixed in orientation or they can be set to track the sun or a reference vector.
Before we add the surfaces themselves, we must define specific attributes for the material composition of the external surfaces. Each material has a specific use case due to its thermal and optical attributes.
Create a surface material
Open the menu to create an external surface and add the following surface materials. You can leave the default temperature rating values.
| Part Number | IR Emissivity (%) | Solar Absorptivity (%) | Diffuse Solar Reflectivity (%) | Specular Solar Reflectivity (%) |
|---|---|---|---|---|
| Aluminum | 60 | 25 | 30 | 20 |
| Solar Panel | 40 | 40 | 20 | 20 |
| Radiator | 70 | 20 | 15 | 10 |
Create a surface
Now that you have added the surface materials for surfaces, you must add external surfaces to the agent. You can use the checkboxes in the table below to keep track of which external surfaces you have added. Add the following external surfaces to the agent:
| Surface Name | Area (m2) | Motion Type | Anti-track? | Normal Vector | Centroid [X, Y, Z] | Surface Material | | :------------------------------: | :------------------: | :----------: | :----------------------------------------: | :-----------: | :----------------: | :--------------: | ------------------------- | | +X Surface | 1 | Fixed | | +X | [1, 0, 0] | Aluminum | | | -X Surface | 1 | Fixed | | -X | [-1, 0, 0] | Aluminum | | | +Y Surface | 2.5 | Fixed | | +Y | [0, 0.5, 0] | Aluminum | | | -Y Surface | 2.5 | Fixed | | -Y | [0, -0.5, 0] | Aluminum | | | +Z Surface | 2 | Fixed | | +Z | [0, 0, 0.5] | Aluminum | | | -Z Surface | 2 | Fixed | | -Z | [0, 0, -0.5] | Aluminum | | | Solar Panel +Y Fixed Surface | 0.5 | Fixed | | +Y | [-1, 0.5, 0] | Solar Panel | | | Solar Panel -Y Fixed Surface | 0.5 | Fixed | | -Y | [-1, -0.5, 0] | Solar Panel | | | Solar Panel +Y Sun Track Surface | 4 | Sun Tracking | | +Y | [0, 3, 0] | Solar Panel | | | Solar Panel -Y Sun Track Surface | 4 | Sun Tracking | | -Y | [0, -3, 0] | Solar Panel | | | Solar Panel +Y Sun Track Back | 4 | Sun Tracking | | +Y | [0, 3, 0] | Radiator | | | Solar Panel -Y Sun Track Back | 4 | Sun Tracking | | -Y | [0, -3, 0] | Radiator | |
Fields of View
Fields of view are used for optical sensors, data handling, and condition logic. Fields of view can have conditions associated with them to determine when the field of view will be active, but we will not add conditions to Wildfire's fields of view.
Create a field of view
Add the following circular field of view:
| Field of View Name | Boresight Body Frame Vector | Field of View Type | Conical Half Angle |
|---|---|---|---|
| Crosslink FoV | Crosslink Boresight | Circular | 10° |
Add the following rectangular field of view:
| Field of View Name | Boresight Body Frame Vector | Field of View Type | Vertical Axis Body Frame Vector | Height Half Angle | Width Half Angle |
|---|---|---|---|---|---|
| Star Tracker FoV | +Z | Rectangular | +X | 5° | 6° |
Subsystems
Here you can see a listing of every component on the spacecraft organized by subsystem. You can also add custom components and define their temperature ratings and thermal capacitance. Custom components do not have any special functionality, but they can be associated with power loadings, data handling, and thermal interfaces.
Create a custom component
If you have a grouping of custom components, you can add a custom subsystem group. This custom subsystem serves only to organize the custom components that you may add and does not have any special behavior.
Create a custom subsystem
Add a custom subsystem called "Payload". Then, add the custom components in the table below. You can leave the default values for initial temperature, temperature ratings, and thermal capacitance. We will update the temperature ratings and thermal capacitance of Wildfire's components in the Thermal Ratings & Capacitance section.
| Subsystem | Component Name |
|---|---|
| Command & Control | Flight Computer |
| Structure | Spacecraft Chassis |
| Structure | Control Chassis |
| Structure | Power Chassis |
| Structure | Communication Chassis |
| Payload | Payload Chassis |
| Payload | Payload Computer |
| Payload | Payload Camera |