WM Satellite Tracker
500 active satellites. Live telemetry. NORAD-standard orbital physics, all running in the browser.
This is an internal project. WM builds them to explore capability and share with the community — working models of what’s possible when there’s no brief constraining the scope. The satellite tracker is the most technically ambitious one: real-time orbital physics, live satellite data, 3D rendering, all in the browser.
WM Satellite Tracker is a real-time 3D orbital visualiser. Live data from Celestrak. SGP4/SDP4 propagation — the same standard NORAD uses. Time acceleration to 300× real speed. 3D models of the ISS, Hubble, GOES, and TDRS at actual orbital positions. No backend computing positions. The browser does it all. Live at satellite-tracker.workingmodel.co, open source on GitHub.
Product: WM Satellite Tracker
Live: Visit live site ↗
Built by: Working Model Inc
Goal: Demonstrate creative technology capability — 3D data visualisation at production quality, built as internal R&D.
Key differentiator: SGP4/SDP4 orbital physics running in-browser on 500+ live satellites. The physics are real.
Key Challenges & Strategic Objectives
- The physics are real and computationally expensive. SGP4 accounts for atmospheric drag, Earth’s oblateness, lunar and solar gravity, and dozens of other perturbations. Running it accurately in a browser — fast enough to update 500 objects every animation frame at 60fps — required careful optimisation. Approximation wasn’t available: wrong physics produces wrong positions.
- The scale is deceptive. The ISS orbits at 410 km. Geostationary satellites sit at 35,786 km — nearly 88× higher. Making both visible and comprehensible on a single screen required significant visual calibration. The first version made LEO satellites invisible. The second crowded the frame. The third was right.
- The fallback data had to be real. When Celestrak is unavailable, the tracker falls back to 55 hardcoded satellites. They are actual satellites, with actual orbital elements, in actual orbits. Placeholder data was never considered.
- The background had to be built. The nebula, 9,000-star field, and Milky Way band are generated by custom GLSL shaders — not a texture. A static image would have been undetectable to most users. It wasn’t considered.
Technical Solution & Architecture
Three.js WebGL rendering, SGP4 physics, live Celestrak data, AWS-hosted infrastructure.
1. Orbital Data & Physics
Live TLE data fetched from Celestrak GP endpoints on page load. 500+ active satellites across Starlink, OneWeb, Iridium NEXT, GPS/NAVSTAR, Galileo, GLONASS, ISS, GOES, TDRS, Hubble, and GEO comsats. SGP4/SDP4 runs in-browser — no server computing positions. Time simulation to 300× real speed. Search by satellite name; camera flies to the target.
2. 3D Rendering
Three.js with WebGL. Actual 3D models for ISS, Hubble Space Telescope, GOES weather satellites, and TDRS at actual orbital positions. Custom GLSL shaders generate the star field, nebula, and Milky Way band. Bloom post-processing. Palette: near-black background, cyan for LEO, amber for MEO, magenta for GEO.
3. Infrastructure
AWS S3 + CloudFront CDN, Lambda + API Gateway. Bundle: ~670 KB gzipped. Time to interactive: under 2 seconds on a fast connection.
4. Offline Fallback
55 hardcoded satellites with real orbital elements. When Celestrak is unavailable, the tracker still works. This was never negotiable.
Outcomes & Results
Built across 6 sprints, approximately 3 weeks.
- Satellites tracked: 500+ live, 55 handcrafted fallback.
- Physics: SGP4/SDP4 — the NORAD standard.
- Time acceleration: up to 300×.
- Constellations covered: 12 across LEO, MEO, GEO.
- Bundle size: ~670 KB gzipped.
- Time to interactive: under 2 seconds.
The craft is mostly invisible. The fallback TLEs nobody will ever need. The procedural stars nobody will notice. The scale calibration that took three iterations to feel right. That’s the work that separates a demonstration from a demo.
What This Means
The standard that produced 55 handcrafted fallback satellites nobody will ever need — and a procedurally generated star field nobody will notice was built rather than textured — is the same standard WM brings to every project. The satellite tracker is just the version that’s easy to point to.
Let's Build Something That Works.
Tell us what you’re working on, what you’re stuck on, or what you want to bring to life. We’ll reply quickly, clearly, and with next steps you can act on.
Brought to you by Working Model Inc
