Reentry Casualty Risk Assessment

When a satellite or rocket stage is left to decay naturally, international space governance — UNOOSA's guidelines, COSPAR debris-mitigation practice, and the IADC's technical standards — requires operators to show the reentry is safe for people on the ground before it's ever licensed. This simulator renders the physics behind that check: a 3D Earth with a satellite spiralling down an exponentially decaying orbit, aero-thermal breakup at ~78 km, surviving debris fragments scattered along the ground track, and a live casualty expectancy E_c computed from fragment casualty area and population density. Adjust mass, ballistic coefficient, population density and simulation speed to see when a reentry passes or fails the internationally accepted 1-in-10,000 safety threshold.