The people currently living in space are still concentrated in a thin layer of low Earth orbit, only a few hundred kilometres above the planet. Add the satellites, navigation systems and debris around them, and the part of space humanity actually occupies is surprisingly small.

Switch between the top-down view and orbital bands to see where humans in space are moving and how far above Earth they operate. Turn on the surrounding layers to compare the handful of crewed craft with the much larger machine-made environment around them.

The exhibit combines current crew information with orbital data for crewed spacecraft, selected landmark satellites and larger groups including Starlink, navigation satellites and debris.

The positions are calculated rather than received as live GPS coordinates. Humanity in Numbers loads current orbital element data and propagates each object forward to the selected moment using the SGP4 orbital model. CelesTrak publishes current General Perturbations orbital elements for Earth-orbiting objects, while Satellite.js provides the SGP4/SDP4 calculations used in the browser.

That means the display should be read as a representation of the objects’ predicted orbital positions, not as precision tracking telemetry. Orbital elements describe an orbit at a particular epoch and become less accurate as they age, especially for objects affected strongly by atmospheric drag or manoeuvres. The exhibit refreshes its source data so the calculation can begin from recent orbital elements rather than treating an old orbit as fixed.

The crewed layer identifies people currently living away from Earth and associates them with their occupied spacecraft or station. The International Space Station and China Space Station are both continuously updated operational programmes, so crew membership changes as missions launch, dock and return. NASA publishes current ISS expedition information, while the China Manned Space Agency publishes current China Space Station information and orbital parameters.

In the Top-down view, orbital positions are projected onto a plane centred on Earth so movement around the planet can be followed directly. In Orbital bands, direction around the circle is used mainly to separate objects visually while radial distance shows how high above Earth they operate. The Earth and orbital distances share the same scale at each zoom level, but the satellite dots themselves are deliberately enlarged so they remain visible. This description follows the behaviour of the exhibit code rather than an external data source.

Timelapse does not predict a new orbit from scratch. It propagates the same orbital elements forward through simulated time, letting the motion of the different orbital populations become visible. The further a propagation moves from the epoch of its source elements, the less it should be treated as a precise prediction.

The surrounding layers are selective rather than a complete catalogue of everything orbiting Earth. Their purpose is to give scale and context to the human presence at the centre of the story, not to provide a comprehensive space-situational-awareness tool.