Rocket Simulator

A physics-based rocket trajectory simulation library for Python. Simulate rocket launches with realistic gravitational physics, visualize trajectories, and compare real-world rockets.

Features

• Realistic Physics - Altitude-dependent gravity using Newton's inverse-square law
• Pre-configured Rockets - 13 real-world rockets including Saturn V, Falcon 9, Starship, and more
• Custom Rockets - Create and simulate your own rocket designs
• Beautiful Visualizations - Publication-quality plots with multiple styling options
• CLI & Library - Use as a command-line tool or import as a Python library
• Type-Safe - Full type hints for excellent IDE support
• Well-Tested - Comprehensive test suite with pytest

Quick Start

Installation

# Clone the repository
git clone https://github.com/yourusername/rocket-sim.git
cd rocket-sim

# Install in development mode
pip install -e .

# Or install with development dependencies
pip install -e ".[dev]"

Command Line Usage

# Simulate a preset rocket
rocket-sim --preset "Falcon 9" -o falcon9.png

# Simulate all presets
rocket-sim --all-presets -o comparison.png

# Custom rocket
rocket-sim --mass 50000 --thrust 1000000 --burn-time 120 --name "My Rocket"

# Interactive mode
rocket-sim --interactive

# List available presets
rocket-sim --list-presets

Python Library Usage

from rocket_sim import RocketSimulation, get_preset, Plotter

# Simulate a Falcon 9 launch
config = get_preset("Falcon 9")
sim = RocketSimulation(config)
result = sim.run()

# Print results
print(f"Max Altitude: {result.max_altitude_km:.2f} km")
print(f"Max Velocity: {result.max_velocity:.2f} m/s")
print(f"Flight Time: {result.flight_time:.2f} s")

# Create visualization
plotter = Plotter()
plotter.plot_trajectory(result, filename="falcon9.png")

Compare Multiple Rockets

from rocket_sim import simulate_multiple, get_preset, Plotter, list_presets

# Get all preset configurations
configs = [get_preset(name) for name in list_presets()]

# Run simulations
results = simulate_multiple(configs)

# Compare trajectories
plotter = Plotter()
plotter.plot_multiple_trajectories(results, filename="comparison.png")

Create a Custom Rocket

from rocket_sim import RocketConfig, RocketSimulation, Plotter

# Define custom rocket
config = RocketConfig(
    mass=100_000,       # 100 tons
    thrust=2_000_000,   # 2 MN thrust
    burn_time=180,      # 3 minute burn
    name="My Custom Rocket"
)

# Check thrust-to-weight ratio
print(f"T/W Ratio: {config.thrust_to_weight_ratio:.2f}")

# Simulate and plot
sim = RocketSimulation(config)
result = sim.run()

plotter = Plotter()
plotter.plot_dashboard(result, filename="dashboard.png")

Available Rocket Presets

Rocket	Mass (kg)	Thrust (N)	Burn Time (s)	T/W Ratio
Saturn V	2,900,000	33,800,000	165	1.19
SpaceX Starship	5,000,000	72,000,000	200	1.47
Falcon 9	549,054	7,607,000	162	1.41
Space Shuttle	2,030,000	30,600,000	510	1.54
Delta IV Heavy	733,000	17,840,000	360	2.48
Atlas V	584,000	10,500,000	270	1.83
Ariane 5	777,000	11,600,000	540	1.52
Soyuz-2	308,000	4,150,000	290	1.37
Long March 5	867,000	10,600,000	480	1.25
Vega	137,000	2,310,000	110	1.72
Electron	12,550	240,000	150	1.95
New Shepard	75,000	490,000	110	0.67
Vulcan Centaur	546,700	11,340,000	180	2.11

Physics Model

The simulation uses realistic physics including:

• Gravity: Newton's law of universal gravitation with inverse-square falloff

  g(h) = GM / (R + h)²
  

• Escape Velocity: Minimum velocity to escape gravitational field

  v_esc = √(2GM / (R + h))
  

• Atmospheric Density (optional): Exponential atmosphere model

  ρ(h) = ρ₀ × exp(-h / H)
  

Where:

• G = 6.674×10⁻¹¹ m³/kg/s² (gravitational constant)
• M = 5.972×10²⁴ kg (Earth's mass)
• R = 6.371×10⁶ m (Earth's radius)
• ρ₀ = 1.225 kg/m³ (sea level air density)
• H = 8,500 m (scale height)

Project Structure

rocket-sim/
├── src/rocket_sim/
│   ├── __init__.py      # Package exports
│   ├── physics.py       # Physics calculations
│   ├── models.py        # Rocket and Engine classes
│   ├── simulation.py    # Simulation engine
│   ├── visualization.py # Plotting tools
│   ├── presets.py       # Rocket configurations
│   ├── config.py        # Configuration management
│   └── cli.py           # Command-line interface
├── tests/               # Test suite
├── docs/                # Documentation
├── examples/            # Example scripts
├── pyproject.toml       # Project configuration
└── README.md

Development

Setup Development Environment

# Clone and install with dev dependencies
git clone https://github.com/yourusername/rocket-sim.git
cd rocket-sim
pip install -e ".[dev]"

# Install pre-commit hooks
pre-commit install

Running Tests

# Run all tests
pytest

# Run with coverage
pytest --cov=rocket_sim --cov-report=html

# Run specific test file
pytest tests/test_physics.py

Code Quality

# Format code
black src tests
isort src tests

# Lint
ruff check src tests

# Type checking
mypy src

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes
4. Run tests (pytest)
5. Commit your changes (git commit -m 'Add amazing feature')
6. Push to the branch (git push origin feature/amazing-feature)
7. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Rocket specifications sourced from public NASA and SpaceX data
• Physics equations based on classical orbital mechanics
• Inspired by NASA's trajectory simulation tools