The arrival of a megaconstellation like that of Starlink brings back to the agenda and revisits the question of space pollution. Indeed, the operators of these satellite fleets plan to significantly densify the presence of objects in orbit – and therefore increase the risk of creating new debris – but they also have every interest in keeping said orbits clean. so as not to threaten their business.
Also the choice by Starlink of a rather low orbit for its machines presents a double technical interest: on the one hand, the signal takes less time to travel and, on the other hand, in the event of failure, the Satellites naturally fall back to Earth in a short time because, at the altitude where they are moving, friction against the upper layer of the atmosphere causes them to descend quickly. Of the approximately 3,600 machines that Elon Musk’s company has sent into space, around 300 have already been desorbed.
The main risk therefore does not come from there, as explained by Pierre Omaly, “debris” expert at the National Center for Space Studies (CNES): “In space, many objects are inherited from our parents or our grandparents. There are thus hundreds of stages of old launchers, which measure several meters and which cannot be operated. One recent post [publié en avril 2021 par la revue scientifique spécialisée Acta Astronautica] lists the fifty most threatening objects: these are not necessarily the largest, but those that cross paths most often. They are like elephants in a china shop. A collision could generate thousands of new pieces of debris. »
This specialist continues: “Until now, we were more in the philosophy of “let’s not create new debris”. But we realized by numerical simulation that, even if we stopped sending objects into space, the number of debris would continue to increase by collision or explosion of the machines that we have already put into orbit…”
Sugar tongs, net, harpoons and robotic arms
Hence the idea, increasingly present in the minds of space agencies, of cleaning up there. To go catch these “elephants” located in orbits high enough to stay there for centuries or more, and to lower them so that they burn up on re-entering the atmosphere.
Sign of these new times, during the last meeting of the IADC (Inter-Agency Space Debris Coordination Committee), in October, in South Korea, “a committee bringing together the thirteen largest space agencies in the world, who meet to find solutions to this problem of debris, it was for the first time discussed the need to remove debris”says Pierre Omaly.
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