It is unlikely that all de-orbited satellites will burn up completely, or that all surviving rocket parts, including unspent fuel, will be successfully dumped in the sea, so damage to property and even life will be an increasing risk. Disposing of satellite remnants in a marine environment has environmental risk, which has been successfully challenged in the past [28,29]. The risk to life and impact on the environment is non-trivial. Based on a population of 16,000 satellites in LEO, it has been estimated that by 2030 the probability of casualties on the ground will rise to 0.1/year (presentation to UN COPUOS committee, quoted in [30]). Descending debris also poses a risk to aircraft. From the same UN presentation, predictions suggest a 1 in a 1000 chance of an aircraft being struck each year, but with some 300 passengers per aircraft, that means 0.3 casualties per year. A possible population of 100,000 satellites increases the casualty rate by many times. The first aircraft strike or ground casualty is only a matter of time.
Animal and plant ecosystems
Numerous animal species ranging from insects to mammals to birds are known to orient themselves during migration and foraging activities using the stars and the Milky Way [31– 34]. Roughly 40% of bird species migrate, and roughly 80% of those migrating species migrate at night, many of them using the stars to navigate [35,36]. While we cannot yet know whether those species will be sensitive to many additional "stars" appearing to move rapidly across the sky, reasonable predictions of potentially significant harm are already appearing in the scientific literature [37]. It is also possible that integrated sky brightness may increase significantly, with further disruption to some species and ecosystems. [38, 7, BioEnvironment Report].
Space Weather issues
Activity from the Sun, called space weather, has dramatically affected satellites in the past. Charged particles are ejected from the Sun at high speeds during solar storms, and these charged particles can have negative effects on the on-board electronics in satellites, causing them to temporarily shut down in a “safe mode” until a reset command can be issued from the ground. Satellites can even have their electronics overloaded and be permanently disabled. With the huge increase in the number of satellites and the increased collision risk, active collision avoidance by many satellites will be frequent. If satellites are disabled, even temporarily, they will lose the ability to manoeuvre around hazards and the collision risk will increase dramatically every time a satellite enters “safe mode” or is disabled. The frequency and intensity of solar storms varies in an eleven-year cycle and the next Solar Maximum, when solar activity will be at its peak, is predicted to be in 2024-2025. The population of satellites by then is expected to be several times higher than it is today and it is worth noting that a relatively minor geomagnetic storm resulted in an unexpected descent and burnup of 40 Starlink satellites in February 2022.
Conclusion
We have laid out the argument that there is an urgent need for orbital space to be considered part of the human environment. Adequately addressing the problems detailed above will require a holistic approach that treats orbital space as part of the environment, and worthy of environmental protection through existing and new policies, rules and
