🚀 Live Demo · 📡 Celestrak · 📜 MIT License
"Osservare la Terra da lassù significa capire quanto sia fragile da quaggiù." — Alessandro Pezzali
CubeSat Constellation is an interactive Progressive Web App that visualizes satellite orbits in real time on a 3D globe, using TLE (Two-Line Element) data and accurate SGP4/SDP4 propagation. Load a full constellation from the built-in live Celestrak catalog, or paste any standard TLE block directly.
| Feature | Details |
|---|---|
| 🌍 Interactive 3D globe | CesiumJS + OpenStreetMap tiles, day/night shading |
| 🛰 Multi-satellite constellation | N satellites simultaneously, each with its own color and orbit |
| 📡 Live Celestrak catalog | 10 curated satellites across 4 categories, TLEs fetched fresh |
| 📊 Real-time telemetry | Altitude, velocity (from prop.velocity), real orbital period, lat/lon |
| ☀️ Sun tracking | Subsolar point, azimuth/elevation, dynamic day/night terminator |
| 🌑 Eclipse Tracker | Real-time shadow/light state per satellite with countdown to next transition |
| 📻 Doppler Shift | Real-time range rate + Δf + observed frequency for ham radio (default 437.800 MHz, GS fallback Rome) |
| 🕐 TLE Age Indicator | Color-coded badge (green <24h, yellow 24–48h, orange 48–72h, red >72h) + auto-refresh every 6h (online only) + manual refresh button |
| 🗺 Map links | Google Maps and OpenStreetMap centered on the satellite |
| 📲 Installable PWA | Works offline on desktop and mobile (iOS, Android, macOS, Windows) |
git clone https://github.com/pezzaliapp/CubeSat_Constellation
cd CubeSat_Constellation
python3 -m http.server 8080
# Open http://localhost:8080Note: Serve via HTTP (not
file://) to enable the Service Worker and offline mode.
- Open the 📡 Satellite Library panel and click any satellite to fetch its live TLE from Celestrak
- Or paste one or more TLE blocks directly in the text field (Celestrak 2-line or 3-line format)
- Click
▶️ Simula — the satellite (or constellation) appears on the globe - Use ⏯️ Play/Pause and 🔄 Reset to control the simulation
- Click 🗑 Cancella to clear the TLE field and start a new constellation from scratch
TLE data is fetched live from Celestrak via their public GP endpoint:
https://celestrak.org/NORAD/elements/gp.php?CATNR={norad}&FORMAT=TLE
No registration or API key required.
/index.html — HTML shell
/app.js — Core logic: propagation, rendering, telemetry, catalog
/styles.css — Dark space layout, mobile-safe
/manifest.json — PWA manifest
/service-worker.js — Offline cache (cache-first strategy)
/CHANGELOG.md — Version history
/ANALISI_INIZIALE.md — Technical analysis and feature roadmap
CubeSat Constellation è una Progressive Web App interattiva che visualizza in tempo reale le orbite di uno o più satelliti artificiali su un globo 3D, a partire dai dati TLE (Two-Line Elements) con propagazione SGP4/SDP4 accurata. Puoi caricare una costellazione intera dal catalogo integrato con TLE live da Celestrak, oppure incollare qualsiasi TLE standard.
| Funzione | Dettaglio |
|---|---|
| 🌍 Globo 3D interattivo | CesiumJS + tile OpenStreetMap, ombreggiatura giorno/notte |
| 🛰 Multi-satellite | N satelliti simultanei, ognuno con colore e orbita propria |
| 📡 Libreria Celestrak live | 10 satelliti in 4 categorie, TLE aggiornati in tempo reale |
| 📊 Telemetria live | Altitudine, velocità (da prop.velocity), periodo orbitale reale, lat/lon |
| ☀️ Posizione del Sole | Punto subsolare, azimut/elevazione, terminatore giorno/notte |
| 🌑 Eclipse Tracker | Stato luce/ombra in tempo reale per ogni satellite con countdown alla prossima transizione |
| 📻 Doppler Shift | Range rate + Δf + frequenza osservata in tempo reale per radioamatori (default 437.800 MHz, GS fallback Roma) |
| 🕐 TLE Age Indicator | Badge colorato (verde <24h, giallo 24–48h, arancione 48–72h, rosso >72h) + auto-refresh ogni 6h (solo online) + pulsante refresh manuale |
| 🗺 Link mappa | Google Maps e OpenStreetMap centrati sul satellite |
| 📲 PWA installabile | Funziona offline su desktop e mobile |
git clone https://github.com/pezzaliapp/CubeSat_Constellation
cd CubeSat_Constellation
python3 -m http.server 8080
# Apri http://localhost:8080- Apri il pannello 📡 Libreria satelliti e clicca un satellite per caricare il TLE live
- Oppure incolla uno o più TLE nel campo di testo (formato Celestrak 2 o 3 righe per satellite)
- Premi
▶️ Simula — il satellite (o la costellazione) appare sul globo - Usa ⏯️ Play/Pause e 🔄 Reset per controllare la simulazione
- Usa 🗑 Cancella per svuotare il campo e costruire una nuova costellazione
Ideas sourced from the initial technical analysis.
| # | Feature | Status |
|---|---|---|
| 1 | Multi-satellite constellation mode | ✅ Done (v6) |
| 2 | Ground station + visibility cone + AOS/LOS | ✅ Done (v9) |
| 3 | Eclipse tracker — sunlit vs. shadow orbit coloring | ✅ Done (v10) |
| 4 | Doppler shift calculator for ham radio operators | ✅ Done (v10.3) |
| 5 | Pass predictor with .ics calendar export | ⏳ Planned |
| 6 | AR sky compass mode (mobile, DeviceOrientation API) | ⏳ Planned |
| 7 | Orbital decay & re-entry estimator (BSTAR drag term) | ⏳ Planned |
| 8 | Live Celestrak satellite catalog | ✅ Done (v8) |
| 9 | Communication coverage footprint (EllipseGraphics) | ⏳ Planned |
| 10 | Historical replay with annotated events timeline | ⏳ Planned |
Geolocation (upcoming — Ground Station feature)
The HTML5 Geolocation API (navigator.geolocation) requires a secure context (HTTPS or
localhost). It will not work if the app is opened directly via file://. When deployed on
GitHub Pages or any HTTPS host, it works correctly.
Celestrak API rate limits The live TLE fetch uses Celestrak's public endpoint without authentication. For personal and educational use this is fine. Heavy automated usage (many rapid fetches) may hit undocumented rate limits. For production/high-traffic scenarios, cache TLEs locally or register for Space-Track direct access.
PWA offline installation
The Service Worker and "Add to Home Screen" prompt are only available when the app is served
over HTTPS on a public domain (or localhost). Opening index.html directly from disk
activates neither. GitHub Pages provides free HTTPS hosting and enables full PWA features.
| Technology | Role | Link |
|---|---|---|
| CesiumJS | 3D globe, entity rendering, clock & timeline | cesium.com |
| satellite.js | SGP4/SDP4 orbital propagation from TLE | github.com/shashwatak/satellite-js |
| Celestrak | Public TLE data source (GP element sets) | celestrak.org |
| OpenStreetMap | Map tiles for the globe base layer | openstreetmap.org |
Map tiles © OpenStreetMap contributors — ODbL license.
Alessandro Pezzali — pezzaliAPP.com Cultura digitale tra codice, orbite e immaginazione.
MIT License — © 2025-2026 Alessandro Pezzali Free to use for educational, scientific, creative and commercial purposes. See LICENSE for the full text.