Satellite Debris Shield 2D: Orbital Collision Avoidance & Kessler Cascade

The 3D "Satellite Debris Shield" page runs on a shared decorative particle-flow template with generic sliders labelled "Intensity" and "Stability" — it never modeled an actual orbit or a real collision. This 2D companion instead builds the mechanic the title promises: every debris fragment and the satellite itself circle Earth on its own shell at the angular rate Kepler's third law assigns it, so shells with different altitudes constantly lap one another and produce genuine conjunctions. Dodging one costs a real two-impulse Hohmann Δv computed from the vis-viva equation, not an arbitrary number — run the budget dry and the satellite can no longer maneuver. A dodge that fails is a hit: shield integrity drops and the debris fragments into two or three smaller pieces on nearby shells, the same runaway feedback loop astronomers call Kessler syndrome.