Examining Short-term Space Safety Effects from LEO Constellations and Clusters

The large satellite constellations currently planned and deployed in Low Earth Orbit bear some similarities with the clusters of derelict objects abandoned in some altitude bands in LEO. Given the similarities between the two physical situations, a tool developed at IFAC-CNR for long-term constellation impact analysis is applied in two new ways: (1) focus on immediate (i.e., 1-20 years) effects from constellation deployment and execution and (2) apply to the accumulation of massive derelict objects in a restricted region of space (i.e., clusters). The intra-group collision probability caused by the repeated orbital crossing between the members of two selected constellations and of some of the clusters of objects in LEO are computed, cumulated over the time span of the analysis (20 years) and compared. While the collision probability obtained in the case of the constellation could be efficiently mitigated by proper management and operations (i.e., debris mitigation practices and collision avoidance), the high level of risk associated with the clusters of derelict uncontrolled objects cannot be avoided, unless pro-active actions are undertaken to remove the large targets from the space.