Conceptual Study on Laser Networks for Near‐Term Collision Avoidance for Space Debris in the Low Earth Orbit

Abstract

Due to the increasing amount of space debris, several laser‐based concepts for orbit modification have been proposed in the recent years. Since the sparse availability of pulsed lasers with high energy (> 10 kJ) seems to render laser‐ablative debris nudging for collision avoidance into a solution only for the long run, alternative options which can be realized earlier are mandatory to counter the rapidly increasing number of space debris in low Earth orbit. In this regard, high‐power CW lasers (> 10 kW) have been proposed in the past for debris nudging by photon pressure. With momentum coupling being 3 – 4 orders of magnitude lower than in the case of laser ablation, this might appear as a poor alternative at first glance, but the opposite is the case when a greater number of laser stations are combined forming an international network for laser tracking and momentum transfer (LTMT).

From this viewpoint, we report on our findings on photon momentum transfer to space debris from our work performed under the conceptual study LARAMOTIONS (SSA P3‐SST‐XV) funded by the European Space Agency (ESA) in the framework of ESA’s Space Situational Awareness Program. Commercial availability of high power CW lasers allows for the setup of a network of relatively cost‐efficient laser stations in the next decade. Such an LTMT network would serve for both momentum transfer to space debris as well as for high precision laser tracking as a prerequisite for conjunction alert assessment and high‐power laser beam pointing. Depending on the network size, geographical distribution of stations, orbit parameters and remaining time to conjunction, multi‐pass irradiation enhances the efficiency of photon momentum coupling by 1 – 2 orders of magnitude and has the potential to eventually yield a promisingly significant reduction of the collision rate in low Earth orbit.