Space sustainability through atmosphere pollution? De-orbiting, atmosphere-blindness and planetary environmental injustice

Abstract

Space debris is a major issue for space safety as any collision of a space object with even a small piece of debris can have catastrophic consequences. The most recent dramatic increase of the number of satellites in Earth’s orbit is clearly exacerbating the risks. In this context there is a growing norm of disposal of orbital debris through atmospheric re-entry: space debris is to ‘burn up harmlessly in the atmosphere’, in order to provide for a ‘clean space’. Unfortunately, there is very little data on the environmental impact of deorbiting on atmospheric chemistry and in-situ data collection is practically impossible. The few existing studies – our own modelling included – agree that while the current impact of deorbiting is likely negligible, the projected exponential growth of satellites in LEO could exacerbate the risks. In consequence, space sustainability may come at the expense of damaging the health of the middle and upper atmosphere, with potentially unforeseeable consequences. Against this backdrop, we argue that in order to manage LEO sustainably, we must overcome this – what we call – ‘atmosphere-blindness’: our limited understanding of space-Earth system links through orbital disposal practices and their atmospheric impacts. While there is growing environmental consciousness with regard to outer space, we need to acknowledge that space sustainability is embedded in a wider context of outer space geopolitics, where the benefits and risks of the space infrastructure are distributed highly unequally. In our view it is thus crucially important to undertake more interdisciplinary research on the issue of de-orbiting, as it is not merely a technical environmental problem to be fixed but also an inherently political matter of planetary scale environmental justice.