ensim 1.0.2

EnSim - Professional Rocket Engine & Flight Simulation Platform

EnSim

🚀 Professional Rocket Engine & Flight Simulation Platform

Features • Quick Start • Documentation • Validation • Contributing

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Overview

EnSim is an open-source desktop application for rocket propulsion analysis and flight simulation. It combines NASA-validated thermochemical equilibrium calculations with full 6-DOF trajectory simulation, all within a modern, user-friendly interface.

Whether you're a student learning rocket science, a researcher exploring propulsion concepts, or an engineer performing preliminary design analysis, EnSim provides the tools you need.

✨ Features

🔬 Thermochemical Analysis

• NASA CEA Methodology: Gordon-McBride equilibrium solver with Gibbs free energy minimization
• Comprehensive Species Database: 35+ species including H₂, O₂, CH₄, RP-1, N₂O₄, UDMH, MMH
• High-Temperature Dissociation: Full accounting for H, O, OH, NO, and other radicals
• Validated Accuracy: <2% error vs NASA CEA reference data

🚀 Performance Calculations

• Chamber Temperature: Adiabatic flame temperature with dissociation
• Characteristic Velocity (C)*: Key measure of combustion efficiency
• Specific Impulse (Isp): Both vacuum and sea-level values
• Thrust Coefficient (Cf): With nozzle divergence corrections

🎯 6-DOF Flight Simulation

• Full Rigid Body Dynamics: Quaternion-based orientation (no gimbal lock)
• Adaptive Integration: RK45 Dormand-Prince with automatic step sizing
• Aerodynamic Models: Configurable drag and stability derivatives
• Dense Output: Cubic Hermite interpolation for smooth trajectories

🎲 Monte Carlo Analysis

• Landing Dispersion: CEP and 3-sigma confidence ellipses
• Performance Variability: Statistical analysis of Isp, thrust, burn time
• Parallel Processing: Multi-core execution for thousands of runs
• Visualization: Scatter plots, histograms, and probability contours

🎨 Modern User Interface

• Mission Control Aesthetic: SpaceX-inspired dark theme with neon accents
• Real-time KPI Dashboard: Live display of key performance metrics
• Interactive 3D Visualization: PyVista-powered nozzle and trajectory display
• Professional Exports: CSV data, Markdown reports, STL/OBJ/PLY 3D models

🚀 Quick Start

Prerequisites

• Python 3.10 or higher
• pip package manager

Installation

Option 1: Install from PyPI (Recommended)

pip install ensim

Option 2: Install from Source

# Clone the repository
git clone https://github.com/SpaceEngineerSS/EnSim.git
cd EnSim

# Create virtual environment (recommended)
python -m venv venv

# Activate virtual environment
# Windows:
venv\Scripts\activate
# Linux/macOS:
source venv/bin/activate

# Install dependencies
pip install -r requirements.txt

Running EnSim

# Launch the GUI application
python main.py

# Run with validation tests
python main.py --test

First Simulation

1. Select Propellants: Choose fuel (e.g., H₂) and oxidizer (e.g., O₂)
2. Set Conditions: Enter O/F ratio, chamber pressure, expansion ratio
3. Run Simulation: Click "RUN SIMULATION" to calculate performance
4. Analyze Results: View KPIs, graphs, and 3D nozzle visualization

📖 Documentation

Document	Description
ARCHITECTURE.md	System design and physics overview
docs/THEORY.md	Mathematical formulation and equations
docs/VALIDATION.md	NASA CEA comparison results
CONTRIBUTING.md	Contribution guidelines
CHANGELOG.md	Version history

✅ Validation

EnSim is rigorously validated against NASA CEA, the industry standard for rocket propulsion analysis.

Validation Summary

Propellant Combination	T_chamber Error	Isp Error	Status
LOX/LH₂	1.76%	1.41%	✅ Pass
LOX/CH₄	0.48%	1.07%	✅ Pass
LOX/RP-1	0.49%	0.86%	✅ Pass
N₂O₄/UDMH	0.56%	0.85%	✅ Pass

Overall Accuracy: Average error <1% across all validated cases

See VALIDATION.md for detailed comparison data.

🏗️ Architecture

EnSim/
├── 📁 src/
│   ├── 📁 core/                 # Physics Engine (Numba JIT)
│   │   ├── chemistry.py         # Gibbs equilibrium solver
│   │   ├── propulsion.py        # Nozzle flow calculations
│   │   ├── flight_6dof.py       # 6-DOF dynamics
│   │   ├── integrators.py       # RK45, Hermite interpolation
│   │   ├── monte_carlo.py       # Dispersion analysis
│   │   └── thermodynamics.py    # NASA polynomial evaluation
│   │
│   ├── 📁 ui/                   # User Interface (PyQt6)
│   │   ├── windows/             # Main window, dialogs
│   │   ├── widgets/             # Custom widgets
│   │   └── workers.py           # Background threads
│   │
│   └── 📁 utils/                # Utilities
│       ├── nasa_parser.py       # Thermo data parser
│       └── exporters.py         # Data export functions
│
├── 📁 data/                     # NASA thermodynamic database
├── 📁 tests/                    # Test suite (pytest)
├── 📁 docs/                     # Documentation
└── 📁 assets/                   # Icons, stylesheets

🔧 Technology Stack

Component	Technology	Purpose
GUI	PyQt6	Modern cross-platform interface
Numerics	NumPy, SciPy	Array operations, optimization
Acceleration	Numba	JIT compilation for 10-100x speedup
3D Visualization	PyVista	Interactive nozzle/trajectory display
2D Plots	Matplotlib	Scientific plotting
Testing	pytest	Unit and validation tests

🤝 Contributing

We welcome contributions from the community! Whether it's:

• 🐛 Bug Reports: Found an issue? Open a bug report
• ✨ Feature Requests: Have an idea? Suggest a feature
• 🔬 Scientific Issues: Validation concerns? Report a scientific issue
• 💻 Code Contributions: Ready to code? See CONTRIBUTING.md

Development Setup

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

# Run tests
pytest tests/ -v

# Run linting
ruff check src/

# Format code
black src/ tests/

📜 License

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

🙏 Acknowledgments

• NASA Glenn Research Center - Thermodynamic polynomial database
• Sutton & Biblarz - "Rocket Propulsion Elements" reference
• The open-source scientific Python community - NumPy, SciPy, Matplotlib

📚 References

1. Gordon, S. & McBride, B.J. (1994). "Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications". NASA Reference Publication 1311.

2. McBride, B.J., Zehe, M.J., & Gordon, S. (2002). "NASA Glenn Coefficients for Calculating Thermodynamic Properties of Individual Species". NASA/TP-2002-211556.

3. Sutton, G.P. & Biblarz, O. (2017). "Rocket Propulsion Elements". 9th Edition, Wiley.

4. Anderson, J.D. (2003). "Modern Compressible Flow". 3rd Edition, McGraw-Hill.

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