Every fragment moves on its own Kepler orbit: a fixed altitude, inclination and starting phase combine into a circular path around Earth, swept out at an angular speed set purely by that altitude — closer debris laps the planet far faster than debris higher up. When the trajectories of two active fragments cross too closely, a collision fires: both are destroyed and a handful of new, faster-drifting fragments are born from the wreckage — the seed of a Kessler-syndrome cascade where debris begets more debris. A net-collector satellite continuously homes in on the nearest active fragment, captures it on approach, and removes it from orbit for good.
v(r) = √(GM / r) orbital speed at radius r
ω(r) = √(GM / r³) angular speed (period T = 2π/ω)
P(collision) ∝ n · σ · v density n, cross-section σ, relative speed v
- Debris count — how many fragments are seeded in the field; a denser field means shorter distances between orbits and a much higher collision rate.
- Simulation speed — scales how fast time advances, so a slow Kessler cascade can be watched unfold in seconds instead of years.
- Collisions — toggles whether crossing fragments actually collide and cascade; switch it off to see the same field simply drift forever.
- Cleanup — toggles the active-debris-removal (ADR) collector satellite that hunts down and nets one fragment at a time.
Real-world relevance: this is the mechanism behind the Kessler syndrome — a runaway chain reaction of collisions that could eventually make entire orbital shells unusable — and the reason space agencies are investing in active debris removal missions using nets, harpoons and drag sails.