So it’s clear that SpaceX is not operating its Starlink constellation in a cavalier manner. But it’s also clear that the company’s constellation, and those like it, are cause for significant concern going forward.
What should we be worried about?
No credible experts are saying that the Kessler syndrome could happen imminently—a single collision won’t set off a Gravity-style cascade.
But space is getting more crowded, and some orbits, particularly from 520 km to 1,000 km above Earth. A 2025 paper by Hugh Lewis and Kessler (yes, that Kessler) found that some orbital bands in this region have already reached what is known as a “collisional-runaway threshold,” which is to say that any serious collisions there may create new debris faster over time than debris would be naturally removed by the pull of gravity, down into Earth’s atmosphere.
Another concern comes from spent “rocket bodies,” upper stages from rockets that were not properly disposed of after launch. This was more common in decades past, but some launches today still do not reserve enough propellant to properly deorbit a second or third stage. These school bus-sized stages are particularly problematic at altitudes of 840 and 975 km, said LeoLabs space debris expert Darren McKnight. They are winging around uncontrolled, of course. And the higher the altitude, the longer the debris hangs around, from decades to centuries.
Finally, because there is so much stuff flying around orbit, it would be relatively easy for bad actors to start shooting missiles at satellites in low-Earth orbit, creating debris fields that could potentially wipe out communications and cause massive financial damage. The probability of Kessler syndrome becomes much higher if humans start deliberately blowing things up in space. Did we mention that Iran recently became the ninth country to put a domestically built satellite into orbit?
What’s the bottom line?
In the near term, it seems unlikely that space will become unusable. But it will likely become more and more expensive to operate there when considering avoidance technology, people to manage all of this, and propellant for maneuvers. And finding launch windows that avoid known debris will become more difficult.
Longer term, perhaps as early as 15 years from now but more likely longer, a Kessler-syndrome type outcome may start to become increasingly plausible.