🛰️ Orbital Collision Simulation

A real-time 3D visualization of satellite orbits, collision detection, and predictive analysis — built with React, CesiumJS, and Clean Architecture.

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Preview

🌍 Overview

This project simulates and visualizes satellite orbits around Earth, detecting potential collisions and predicting future close approaches (TCA — Time of Closest Approach).

It demonstrates a real-time orbital mechanics system with:

• Dynamic 3D visualization using CesiumJS.
• Real-time collision detection.
• Predictive algorithms for close approaches.
• Visual and textual alert panels.
• An event log of all detected collisions.

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🧠 Core Algorithms

This simulation is driven by simplified orbital mechanics and vector mathematics to approximate real satellite motion.

1️⃣ Orbital Position Calculation — satelliteECEFAtTime()

Each satellite’s position in ECEF coordinates is computed using circular orbit equations:

[ r = R_{Earth} + altitude ] [ u = u_0 + n \cdot t \quad \text{where } n = \sqrt{\frac{\mu}{r^3}} ] [ r_{ECEF} = R_z(\Omega_E \cdot t) \cdot R_z(RAAN) \cdot R_x(inc) \cdot r_{orb} ]

Where:

• ( \mu = 3.986 \times 10^{14} ) m³/s² (Earth’s gravitational parameter)
• ( \Omega_E ) = 7.292115 × 10⁻⁵ rad/s (Earth’s rotation rate)

This ensures satellites orbit while Earth rotates underneath.

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2️⃣ Instant Collision Detection — detectInstantCollisions()

At every simulation step, all satellite pairs are compared: [ d = ||r_A - r_B|| ] If ( d < \text{thresholdKm} ), a real-time alert is raised.

This is a pairwise Euclidean distance check using Cesium’s Cartesian3.distance().

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3️⃣ Predictive Collision Estimation — predictCloseApproaches()

To predict future near-misses, relative motion is modeled as: [ r(t) = r_0 + v \cdot t ] The time of minimum distance: [ t^* = -\frac{r_0 \cdot v}{v \cdot v} ] Then: [ d_{min} = ||r_0 + v \cdot t^*|| ] If ( d_{min} < \text{tcaThresholdKm} ), it’s added as a predicted TCA event.

This approach is computationally light, suitable for real-time visualization.

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🧩 Clean Architecture Design

The project follows the Clean Architecture pattern to separate business logic from the presentation layer:

✅ Each layer has a clear responsibility:

• Domain: Pure math & physics logic
• Application: Simulation control flow
• Presentation: React + CesiumJS visualization

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⚙️ Technologies

Category	Technology
UI Layer	React 18 + Resium
3D Engine	CesiumJS
Architecture	Clean Architecture
Language	JavaScript (ES6+)
Styling	CSS + custom animations

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🛰️ Features

• Real-time orbital visualization (Cesium 3D globe).
• Dynamic orbit trails with glow effects.
• Instant collision detection with alert overlays.
• Predictive close-approach modeling (TCA).
• Log of all detected collision events.
• Follow mode for individual satellites.
• Floating/space-like visual effects via CSS.

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🧭 How to Run

# 1️⃣ Install dependencies
npm install

# 2️⃣ Start the development server
npm start

📊 Example Simulation Setup

To make collisions happen early for testing, two satellites are initialized with opposite orbital inclinations (0° and 180°) and similar altitudes (400 km).
This guarantees an intersection near the equator within the first simulation minute.

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🧮 Mathematical References

• Vallado, D. A., Fundamentals of Astrodynamics and Applications (4th Edition).
• Curtis, H. D., Orbital Mechanics for Engineering Students.
• NASA Conjunction Data Message (CDM) format for TCA representation.

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🧑‍💻 Author

Ali Romia
💼 Software Developer

📜 License

MIT License — Free to use, modify, and distribute with credit.

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🌌 Inspiration

This project was inspired by real-world satellite conjunction analysis systems (NASA, ESA, SpaceX Starlink), simplified for interactive visualization and educational use.