6-DOF Satellite Simulation (VLEO) Using Python

Project Overview

This project is a high-fidelity flight dynamics simulation modeling the 6-Degrees-of-Freedom (6-DOF) motion of a satellite in a Very Low Earth Orbit (VLEO) altitude of 400 km. Unlike standard orbital propagators that only track position, this simulation couples Orbital Mechanics (Translation) with Attitude Dynamics (Rotation).

The core simulation focuses on the unique challenges of VLEO, specifically the "Spice": Aerodynamic Disturbance Torques. At 400 km, the atmosphere is thick enough that drag forces acting on the satellite's Center of Pressure (offset from the Center of Mass) create destabilizing torques. An active Nadir-Pointing Control System is implemented to fight these forces and keep the satellite's sensors locked on Earth.

Objectives

• Simulate Realistic Physics: Model the non-linear coupling between orbital velocity, atmospheric density, and aerodynamic drag.
• Demonstrate VLEO Instability: Visualize how a passive satellite tumbles due to drag torques without active control.
• Implement Attitude Control: Design and test a PD (Proportional-Derivative) controller to maintain a Nadir-pointing orientation.
• Dual Visualization Pipeline: Compare lightweight real-time plotting (Matplotlib) against high-fidelity 3D rendering (VTK).

Future Scope

• Solar Radiation Pressure (SRP): Implementing disturbance torques from solar photons for higher orbits (GEO).
• Reaction Wheel Saturation: Simulating the physical limits of the actuators (momentum dumping).
• Kalman Filtering: Adding sensor noise to the simulation and implementing a filter to estimate true attitude.
• Interplanetary Missions: Adapting the physics engine for Martian or Lunar orbits.

📂 Project Structure & Modules

6 - DOF SATELLITE SIMULATION USING PYTHON
├── README.md                           # Project documentation
├── Report.pdf                          # Detailed technical report of the physics math
├── sat.stl                             # 3D Stereolithography model of the satellite
├── sat_matplotlib_visulaisation.py     # MODULE 1: Fast, lightweight trajectory plotting
├── sat_realistic_orientation_lock.py   # MODULE 2: The "Spiced" physics engine with Earth rotation
├── sat_vtk_visualisation.py            # MODULE 3: High-fidelity graphics engine
├── VLEO_Sat_Sim_24Hr.mp4               # Demo: Long-duration simulation output
├── VLEO_Sat_Sim_w_OrientationLock.mp4  # Demo: Active control system in action
└── VTK Visualisation.png               # Screenshot of the VTK render window

## 📄 License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.