Orbital Shells Screensaver
The Orbital Shells screensaver plots active satellites at their true altitude above the Earth, computed from the mean motion in each orbital element set. It runs in the browser with nothing to install; press ESC to exit.
How the Orbital Shells screensaver works
The saver renders with three.js on your GPU. The library is vendored into this site rather than fetched from a CDN, and is loaded only when a 3D screensaver actually runs.
It reads Celestrak's public catalogue of active satellites, which needs no key.
The scene resizes with the window and releases its WebGL context when the saver stops, so shuffle mode and Multi-view can cycle 3D savers without exhausting the browser's context limit.
If WebGL is unavailable the saver says so on screen rather than showing an empty black box.
A worked example
Altitude comes from Kepler's third law: the mean motion in each element set gives revolutions per day, which converts to a semi-major axis and therefore a height. Plotted that way the catalogue stops being a tangle and becomes structure — a dense band a few hundred kilometres up where Starlink and the ISS live, a sparse middle, and a hard thin ring at 35,786 km where geostationary satellites sit motionless above the equator.
Settings & tips
- Accent and Background recolour the scene; Speed changes the pace of both the motion and the camera.
- Add it to a Multi-view grid, though 3D savers are heavier than the 2D ones and a few per screen is plenty.
- Press ESC at any time to leave fullscreen.
Frequently asked questions
- Are the positions exact?
- No, and the saver is built to show altitude bands rather than to track individual craft. Each satellite is placed on its real orbital plane at its mean anomaly using a circular approximation. Precise positions need full orbital propagation, which is a different job.
- Why is the geostationary ring so sharp?
- Because there is exactly one altitude at which an orbit takes 24 hours, so anything that needs to hover above a fixed point on the ground must be at that height. It is a physical constraint, not a convention.
- Does this need a special browser or plugin?
- No. It uses WebGL, which every current desktop and mobile browser supports. Nothing is installed and no plugin is required.
- Does it cost anything or need an account?
- No. Every screensaver here is free, runs in the browser and needs no sign-up.