The Impact Assessment of Accidental Explosions of Large Constellations on Low Earth Orbit Environment

Because of its large number of satellites, a large constellation (an LC) greatly affects other objects in LEO. Several studies reveal the impact of an LC in LEO missions in various operational scenarios. This study evaluated the environmental impact of an LC explosion in the short and long-term using the Near-Earth Orbital Debris Environment Evolutionary Model (NEODEEM). Although setting mission scenarios and analysis conditions is important in LC simulations, it is difficult to consider all operational scenarios due to the many combinations. Therefore, this study conducted impact assessments of explosions in an LC, concentrating on the number of explosions, orbital altitude, and scaling factor of the explosions. The results indicated that it is not enough for LC to comply with the current requirement of probability of accidental explosions which is less than 0.001 during the operation. This is because, if the rate is applied directly to an LC with thousands of satellites, continuous explosions (i.e., several satellites explode every year) will occur during the duration of LC. The paper also discusses the behavior of fragments from explosions at different altitudes. The explosions at low altitudes have no significant impact in the long term, although it can cause an incremental change in collision risk in the short term. Similarly, the explosions at high altitudes, such as 1,250 km, have only slightly increments of the expected number of collisions, but its impact could last for over 100 years. The probability of explosions of an LC must be carefully determined through a series of simulations based on the number of satellites and the operational orbit of an LC. This paper also discusses what should be considered in future LC design and operations regarding explosion prevention.