What you are looking at
Each dot is one catalogued object, coloured by what it is. The dense blue shell a few hundred kilometres up is Starlink - by far the largest constellation, and the reason the number of active satellites has multiplied since 2019. The orange dots twenty thousand kilometres out are the navigation constellations: GPS, Galileo, GLONASS and BeiDou. The thin ring at 35,786 km is the geostationary belt, where weather and broadcast satellites hover over one spot on the equator.
Grey is debris: fragments from collisions, explosions and anti-satellite tests, most of them smaller than a laptop. Red marks spent rocket bodies. Together they outnumber working spacecraft, which is why the debris layer is worth switching on and off to see how much of near-Earth space it fills. The gold dot labelled ISS is the International Space Station.
How the positions are calculated
The catalogue holds a set of General Perturbations elements for every object - a compact description of its orbit at one moment, called the epoch. Your browser feeds each set to SGP4/SDP4, the model those elements are fitted for, in a background worker, and the graphics card moves every point smoothly between updates.
Near the epoch a position is typically good to about a kilometre. Accuracy then falls off, fastest for objects low enough to feel atmospheric drag, which is why the panel shows how old the elements for each object are. Treat it as an accurate picture of where things are, not as a tool for pointing an antenna or predicting a collision.
Things to try
- Speed up time to 600× and watch Starlink planes sweep round the planet while the geostationary ring stays put over the equator.
- Search for Vanguard 1, NORAD 5 - launched in 1958 and still the oldest human-made object in orbit.
- Turn everything off except debris to see how much of low orbit is fragments rather than spacecraft.
- Pick any satellite to draw its orbit and the dashed track it traces over the ground, then press Follow to ride along.
- Open Overhead to count how many objects are above your horizon at this second - usually a few thousand.
A catalogue you can verify
Most trackers ask you to trust whatever their server sends. This one downloads the same signed release the Orbit Map apps use and checks it in your browser: the release pointer against an Ed25519 public key, the download against the SHA-256 the pointer names, and the unpacked catalogue against a second digest. If any check fails, nothing is drawn.
Your location, if you share it for the overhead list or pass times, is used only inside the page and kept in this browser. It is never sent to us.
Where the data comes from
Orbits come from the public General Perturbations (GP) catalogue published by Space-Track.org for the US Space Force, cross-checked against an independent set from CelesTrak before each release ships. A new release is built four times a day.
Each release is signed with Ed25519 - the same signed catalogue the Orbit Map apps download. Your browser checks that signature and the SHA-256 of every byte before drawing anything, then runs the SGP4/SDP4 model itself. Nothing about what you search for, or where you are, is sent back.
Public GP elements propagated for education. Accuracy degrades with element age. Not for conjunction assessment, navigation or antenna pointing. Earth imagery: NASA Blue Marble and Black Marble. City list: GeoNames, CC BY 4.0.