Impact on collision probability by post mission disposal and active debris removal

The collision probabilities of debris objects with and without Post Mission Disposal (PMD) and Active Debris Removal (ADR) are evaluated and discussed. A debris evolutionary model named NEODEEM was jointly developed by Kyushu University and JAXA for use in predicting future debris populations and calculating collision probabilities. The collision probability in each altitude bin is initially compared with and without PMD or ADR. Then a case involving a large satellite constellation is also discussed. The effective number of debris objects at each altitude for the PMD success rates of the large constellation and the collision probability at each altitude are calculated. The collision probability per unit time will increase when a small satellite utilizes a drag augmentation sail or a tether as a PMD device, but the dwell time will be greatly reduced. A collision with a sail or tether will be non-catastrophic collision. Therefore, the use of such devices will reduce the cumulative collision probability and expected number of debris fragments.