—Objects
—Above HQ horizon
—In LEO
—Mean altitude
—Epoch now
Drag to pan · scroll to zoom · click an object
Above Reston horizon
Below horizon
High orbit (>20,000 km)
Reston HQ
🧮
How this works
Each object is described by a two-line element set — a compact snapshot of its orbit. SGP4 turns those elements plus the current time into a position, accounting for atmospheric drag and the Earth's equatorial bulge. Nothing is pre-recorded; the maths runs in your browser every second.
Highest in our sky
Sorted by elevation above the horizon at our Reston headquarters. Click a row to lock onto that object and draw its ground track.
SGP4 positions drift from truth as element sets age — typically a kilometre or so per day for objects in low Earth orbit. Good enough to point a telescope, not good enough to fly a rendezvous.