Satellite constellations could create spiraling space debris
To date, close to 30,000 satellites have been launched into Earth's orbit, leading to mounting concerns over the debris created when they collide. In a new analysis posted to the preprint server arXiv, Hugh Lewis of the University of Birmingham shows that satellite constellations can grow so large that they cross a critical size beyond which they generate unstable, runaway amounts of debris. The…
In recent years, there has been a surge in commercial space activity, particularly the development of satellite constellations designed for internet access and other services. This expansion has raised concerns about the debris created when satellites collide in orbit. Hugh Lewis, a researcher at the University of Birmingham, has analyzed the potential risks associated with growing constellations and found that they can reach a critical size where they generate destabilizing amounts of debris, leading to a runaway effect.
To investigate this issue, Lewis developed a mathematical model that examines the frequency of satellite and debris interactions in space. By considering factors such as satellite maneuverability and the rate at which satellites are removed from orbit, the model provides a practical tool for assessing the safety of proposed constellations.
Applying this model to 16 constellations, both in the planning stages and already operational, revealed that six of them exceeded a critical size threshold. This threshold marks the point at which debris accumulates unchecked, creating an unstable risk of further collisions.
Three additional constellations fell into an unstable debris accumulation zone, even though they did not fully spiral out of control. This risk is not limited to the largest constellations; smaller groups of satellites can also experience instability due to their orbital arrangements. Surprisingly, even a constellation of just a few hundred satellites can reach a critical point if they lack sufficient collision-avoidance capabilities.
Lewis suggests that implementing modest design changes, such as improving satellite deorbiting techniques or extending their operational lifespan, could mitigate these risks.
The lack of clear, constellation-wide regulations exacerbates the problem, as most safety assessments currently focus on individual satellites rather than the collective risk posed by entire constellations. With over a million new satellite applications pending, Lewis's model offers a valuable method for identifying potential issues before satellites are launched, helping to maintain a clear and safe orbital environment for the vital services we rely on.
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