AstroSustainability: Broadening Horizons
Sustainability is something that is becoming ever more important in our daily lives. We are now more conscientious of the effect our habitual ways of living have on the environment. More recycling, less fossil fuels, and managing our impact on this one planet we inhabit. Yet, as humans launch an increasing number of satellites into orbit, it is clear we need to extend this mentality to our activities in space.
The concept of “Space Sustainability” already has a well understood definition: to use the environment of space to meet the current needs of society without compromising the needs of future generations. Already, firm guidelines have been spearheaded by the World Economic Forum to reduce the amount of debris in orbit (Clift, 2021). Rather than leaving spent rocket boosters to be a potential hazard hurtling into and smashing useful satellites — or even crewed spacecraft — organisations must deorbit any potential debris. Purposefully burning it up in the atmosphere is a preferred option. Or not even sending it up there at all! The newest generation of rockets promise to be partially if not fully reusable, for example SpaceX’s new ‘Starship’ (Rincon, 2021).
A computer-generated image representing the locations (sizes not to scale) of space debris seen from high Earth orbit. The two main debris fields are the ring of objects in geosynchronous Earth orbit (GEO) and the cloud of objects in low Earth orbit (LEO). Source: https://orbitaldebris.jsc.nasa.gov/photo-gallery/
Decluttering low earth orbit is a more urgent need than many realise. With fears of triggering Kessler Syndrome (Bernat, 2020) — as portrayed in the 2013 film Gravity — it is possible that the junk we leave in orbit will crash into each other, creating more debris in a knock-on effect that will wipe out all satellites! Kurzgesagt has made a really cool video explaining both this problem and how it might be overcome: https://www.youtube.com/watch?v=yS1ibDImAYU&ab_channel=Kurzgesagt%E2%80%93InaNutshell. However, given a number of prospective missions planned to take robots and humans further out into the solar system, we also need to think beyond Earth.
AstroSustainability includes all activities outside the atmosphere. Broadly, it refers to exploring and utilising space in a forward thinking, low-impact, sustainable manner. This isn’t anything new! The 1967 Outer Space Treaty outlined that members should avoid harmful contamination of space and other bodies. Planetary protection has been around since a similar time — aimed at preventing contamination of other planets when landing on them with new robots. This has primarily been adhered to in order to prevent false positives of discovering life on Mars, for example, and doesn’t come cheap (Fairén and Schulze-Makuch, 2013)! However, as space exploration moves away from government organisations into private companies, there’s no guarantee these practices will be continued. Especially now there is new interest In-Situ Resource Utilisation (ISRU) on the moon and asteroids. Space mining, so to speak, extracting water and materials at the landing site to sustain missions crewed. Although this plans to make space travel cheaper (without the need to take everything we need with us) it also raises the potential issue for space pollution.
There needs to be continued open discussion about what space represents for humanity. AstroSustainability raises the question of whether everything outside of Earth should be treated as an international zone of science — similar to the Antarctic treaty — or if asteroids and other planets are a new frontier for exploration and exploitation. Either way, we need to reflect on the lessons we’ve only just learnt about responsible behaviour.
Bernat, P., 2020. Orbital satellite constellations and the growing threat of Kessler syndrome in the lower Earth orbit. Inżynieria Bezpieczeństwa Obiektów Antropogenicznych.
Clift, K., (2021) We launched the first sustainability rating for space exploration. Available at: https://www.weforum.org/our-impact/world-s-first-space-sustainability-rating-launched/ (Accessed: 25/02/22)
Fairén, A., Schulze-Makuch, D. (2013) The overprotection of Mars. Nature Geosci 6, 510–511. https://doi.org/10.1038/ngeo1866
Rincon, P., (2021) What is Elon Musk’s Starship? Available at: https://www.bbc.co.uk/news/science-environment-55564448 (Accessed: 25/02/22)