Satellite collisions are a disaster waiting to happen, experts warn

With satellites old and new orbiting alongside each other, serious crashes are inevitable

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In the first half of 2024, satellites belonging to SpaceX's Starlink fleet. performed almost 50,000 collision-avoidance manoeuvres. This reflects the number of satellites orbiting Earth and raises fears about satellite collisions if we continue to launch more in an unchecked fashion. Considering how much of our telecommunications and navigation now comes from space, not to mention the observation data that informs us about climate change, fears of a catastrophic crash -triggering a loss of such essential services are understandable.

But according to Andy Lawrence, Regius Professor of Astronomy at University of Edinburgh, it's more insidious than that. "This idea that eventually there will be some sort of catastrophe is not quite right. It's more like the infamous 'boiling the frog' problem," he says.

Essentially, the idea is that if a frog were dropped into boiling water, it would instantly leap out.

But if it were placed into cold water to which heat was gradually applied, it wouldn't perceive the danger and be boiled alive. "It's exactly like climate change. You know it's getting gradually worse, but where do you say 'stop', and how do you manage to make it stop?" says Lawrence.

To circle the Earth, a satellite has to move at a minimum of 7.8km/s (4.8 miles/s). At this velocity, collisions would release an enormous amount of energy, shattering the spacecraft involved and producing large clouds of debris that could destroy other satellites.

Such crashes have already been happening: in 2009, the functioning US satellite Iridium 33 and the inoperable Russian Cosmos 2251 collided at 11.7km/s (7.3 miles/s), producing more than 2,000 pieces of trackable debris and many smaller pieces.