Can 80,000 computing satellites share low Earth orbit without crashing into each other?
A plain-language guide to the LEO Mega-Constellation Collision Explorer
Open the interactive model Read the technical report (PDF) Source code on GitHub
What this is about
Several organizations are proposing to move data centers into space: fleets of tens of thousands of satellites doing AI computation in orbit. Computers produce heat, and in space the only way to get rid of heat is to radiate it away from large panels. Large panels make large targets. This tool asks a simple question with serious consequences: if you fly 80,000 satellites, each the size of half a tennis court, in the same band of low Earth orbit, how often would they collide?
The headline answer
Each satellite would have roughly a 5% chance per year of being hit. This is the "natural" rate: it measures how hard the collision-avoidance autopilot must work, not how many collisions actually happen. With avoidance that succeeds 99.9% of the time, actual losses drop to about 2 per year.
Four consequences follow from the physics, and they do not depend on fine details:
You cannot fix this with geometry. Spreading the fleet across a thicker band of altitudes dilutes the risk, but to reach one collision per year you would need to fill space out beyond the geostationary belt, 40,000 km up. No realistic orbit design makes the problem go away; only active steering, smaller satellites, or fewer of them do.
The stakes compound. At this density, the debris from a single breakup is likely to cause further collisions over the following years, each producing more debris: the runaway known as the Kessler cascade. You cannot dodge debris too small to track, so prevention and the reliable disposal of dead satellites carry nearly all the weight.
Bigger radiators mean more collisions, in direct proportion. Twice the panel area, twice the collision burden; and the burden grows with the square of the number of satellites. Every additional unit of computing power in orbit carries a proportional collision tax.
Where and how fast matters. Collisions concentrate at high latitudes, where the orbital planes cross, and typical impact speeds are 10 to 15 km/s, around twenty times faster than a rifle bullet. Almost any hit is destructive.
How the model works, in one paragraph
The tool contains two physical models. The first treats satellites like molecules of a very thin gas bouncing around a spherical shell, a classic approach from the 1970s. The second respects real orbital mechanics: every satellite follows an orbit, and at any point in space only certain velocities are possible. The second model is the trustworthy one; the first is the benchmark. Their agreement within about 25% is itself a finding, and the orbital model was checked against a brute-force simulation that tracked thousands of orbits and counted every close approach: prediction and count agreed within 3%.
How to explore the problem yourself
Open the interactive model. The left panel sets the scenario, the cards at the top update instantly, and the 3D view shows a sample of the constellation: satellites are light blue where calm and flash red where the local collision risk concentrates; a 💥 marks a collision at the model's natural rate in simulated time.
| Try this | What you will see |
| Drag "Radiator area" down | Collisions fall in direct proportion: the radiator-size tax. |
| Drag "N satellites" up or down | Collisions scale with the square of fleet size. |
| Move "Avoidance failure" | The difference between natural workload and actual residual losses. |
| Switch "Orbit regime" to all Sun-synchronous | A popular orbit choice (convenient for solar panels and radiators) that raises the collision rate about 40%, because all near-polar orbital planes cross each other at steep angles. |
| Set "Radial profile" to a single thin shell | Concentrating everyone at one altitude multiplies the rate about 30 times. |
| Open the "Satellite scale" tab | The satellite next to a city bus, a tennis court, an ISS solar wing, and Hubble, to make the size concrete. |
| Watch the cascade card | Whether one breakup would stay contained (green) or run away (red), and the fleet size where that boundary sits. |
What this model does not say
It does not say orbital computing is impossible; it says the viability rests on operations, not on orbit geometry. It does not predict any specific company's system; parameters are adjustable precisely so assumptions can be questioned. It simplifies: circular orbits, randomized orbital planes, an idealized avoidance system summarized by a single reliability number, and a deliberately simple cascade criterion. And it is an AI-generated model under verification: treat every number as provisional until checked. The mathematics, assumptions, and validation are documented in the technical report.
Feedback
If you spot a bug, disagree with an assumption, or have comments or feedback, please write to golkar@tum.de. The complete source code, including the Python engine, the Monte Carlo validation, and this site, is open at github.com/agolkar/orbit-collisions (MIT license).