About the tracker
Real-time satellite tracking for the ISS and other spacecraft
WhereIsISS is a free browser-based tracker for the International Space Station, Starlink-1008, Hubble, and Voyager. It combines public orbital data with an interactive 3D globe so visitors can see where each object is above Earth or in deep-space context.
Updated display
Position estimates refresh every second in the browser.
Public data
Orbital elements come from public satellite data providers.
Educational use
Built for learning, visualization, and casual tracking.
Frequently asked questions
How does the ISS tracker work?
WhereIsISS uses public two-line element sets, usually called TLEs, and propagates the orbit in your browser with satellite.js. This lets the marker update smoothly without waiting for a remote position API on every frame.
How often does the position update?
The displayed position updates every second. Fresh orbital elements are requested from the server periodically, and the orbit path is rebuilt less often so the globe does not flash while you watch it.
Why can the position differ from another tracker?
Small differences are normal. Trackers may use different TLE snapshots, propagation models, update intervals, or live correction feeds. For public viewing and educational use, the displayed position is a practical real-time estimate.
What data sources are used?
The app uses CelesTrak for current TLE orbital data, WhereTheISS as an optional ISS position reference, and public NASA/JPL data for deep-space context where available. Globe textures are loaded from public CDN assets.
Can I use this for mission-critical tracking?
No. WhereIsISS is built for education, visualization, and casual satellite tracking. It should not be used for spacecraft operations, collision avoidance, radio pointing, or safety-critical decisions.
Data accuracy note
Satellite positions are estimates based on publicly available orbital data. The tracker is useful for understanding current location, ground track, altitude, and speed, but orbital data can age and external data providers can be temporarily unavailable.