Investigating the risks of debris-generating ASAT tests in the presence of megaconstellations

TL;DR

This paper assesses the increased collision risks posed by debris from anti-satellite tests in the context of expanding megaconstellations, highlighting significant probabilities of satellite impacts in future LEO environments.

Contribution

It models collision risks from ASAT debris in megaconstellation environments, emphasizing the heightened danger compared to past scenarios.

Findings

Over 25% chance of satellite collision in a 65,000 satellite constellation after a single ASAT test.

Impacts are likely for debris as small as 3 mm in size.

Significant collision probabilities also found for the 2021 Russian ASAT test.

Abstract

The development of large constellations of satellites (i.e., so-called megaconstellations or satcons) is poised to increase the number of LEO satellites by more than an order of magnitude in the coming decades. Such a rapid growth of satellite numbers makes the consequences of major fragmentation events ever more problematic. In this study, we investigate the collisional risk to on-orbit infrastructure from kinetic anti-satellite (ASAT) weapon tests, using the 2019 Indian test as a model. We find that the probability of one or more collisions occurring over the lifetime of ASAT fragments increases significantly in a satcon environment compared with the orbital environment in 2019. For the case of 65,000 satellites in LEO, we find that the chance of one or more satellites being struck by ASAT fragments of size 1 cm or larger is more than 25% for a single test. Including sizes down to 3 mm in our models suggests that impacts will occur for any such event. Finally, we apply our methods to examine the November 2021 Russian ASAT test, also finding a significant collision probability over the lifetime of the fragments. The heavy commercialization of LEO demands a commitment to avoiding debris-generating ASAT tests.