Specification documents for Spacecraft

1. Overview

1. Functions

The Spacecraft class is the base class to define the following basic features of spacecraft.
- Component information
  - Clock Generator
  - The base class of components (InstalledComponents)
- Dynamics information
  - Attitude
  - Orbit
  - Thermal
  - Relative Information
- Local environment
- Disturbance
- Structure
Users can make user defined spacecraft by inheriting this class.

2. Related files

src/simulation/spacecraft/spacecraft.cpp, .hpp
- The Spacecraft class is defined here.
src/simulation/spacecraft/sample_spacecraft/sample_spacecraft.cpp, .hpp
- An example to make user defined spacecraft with the Spacecraft class.

3. How to use

See Sample Spacecraft
Usually, users just need to consider the user defined components. The disturbance, dynamics of the spacecraft, and etc are already considered in this base class.

2. Explanation of Algorithm

1. `Initialize` function

1. overview

Initialize all members
There are two functions with same name
- One is for single satellite case
- The other is for multiple satellite case to consider relative information

1. `Update` function

1. overview

Update states or calculations for spacecraft

2. inputs and outputs

Input
- Simulation time
Output
- NA

3. algorithm

Clear the force and torque acting on the spacecraft to zero.
Update the local environment around the spacecraft
- The previous spacecraft position and attitude are used.
Update the disturbance acting on the spacecraft
- The local environment information and the previous spacecraft position and attitude are used.
Update the components behavior mounted on the spacecraft
- The components measure the state or generate force/torque.
Add force and torque acting on the spacecraft
- The force and torque from the disturbances
- The force and torque from the components
Propagate the dynamics of the spacecraft
- Attitude and Orbit

3. Results of verifications

NA

4. References

NA