TLE Decoder
Paste a NORAD TLE string. The decoder reads the epoch, orbital elements, and derived semi-major axis, then propagates the satellite to the current UTC moment via SGP4 — same library powering the Starlink layer in our Universe scene.
Orbital elements
- Name
- ISS (ZARYA)
- NORAD ID
- 25544
- Intl. designator
- 98067A
- Epoch (UTC)
- 2024-01-01 12:00:00
- Inclination
- 51.640°
- Eccentricity
- 0.0001000
- Mean motion
- 15.4983 rev/d
- Period
- 92.91 min
- Semi-major axis
- 6795.4 km
- Apogee
- 425.0 km
- Perigee
- 423.7 km
Current sub-satellite point
- Latitude
- -0.5891°
- Longitude
- 171.1405°
- Altitude
- 317.0 km
- Speed
- 7.719 km/s
Current ground track point
How it works
A Two-Line Element set is the standard 1960s-vintage format NORAD still publishes for every catalogued object in Earth orbit. Each TLE encodes a mean Keplerian fit at a specific epoch; SGP4 ("Simplified General Perturbations 4") propagates that fit forward, accounting for atmospheric drag and Earth's oblateness. Accuracy is best within ±1 week of the epoch and degrades steadily afterward — refresh your TLEs from Celestrak.
The current sub-satellite point is the geodetic projection of the satellite onto Earth's surface (the spot directly below). We re-propagate every 5 seconds so the dot drifts across the map. For a 6,000-satellite live constellation rendered the same way, see /universe.