[JumpCrisscross]

> What is that threshold?

Way beyond anything we can currently achieve with current and planned launch capacity or radio technology.

> that object can get destroyed; which means it will start deorbiting and with a chance to hit some other object below

Got it, altitude.

Yes, in theory. In practice, the odds of that happening are vanishingly low. If it did happen, the volumes we're talking about are still so big that you'd struggle to come up with a way to cause a third collision even if we remove satellites' abilities to marginally change their orbits.

[nicce]

> Way beyond anything we can currently achieve with current and planned launch capacity or radio technology.

How are you so sure, when scientist have been debating this for decades?

> Got it, altitude.

Quibbling isn't an argument.

[JumpCrisscross]

> when scientist have been debating this for decades?

They have been. That's what I'm basing my arguments on.

You've been mentioning a ca. 70,000-bird limit. I think that comes from Bongers & Torres [1]. Their paper runs LEGEND (LEO-to-GEO Environment Debris Model). It does not distinguish between LEO and GEO. That's material because the natural decay period for an object in LEO is on the order of months to years, for LEO, to decades to centuries, for GEO.

Kessler in GEO? Real problem. If you wanted to be a space terrorist, you could probably engineer a cascade today that would make large sections of GEO unusuable for decades if not centuries. The point is that isn't possible for LEO, where you may make a mess in a few orbits for a few years at best.

> Quibbling isn't an argument

Sorry, wasn't quibbling. I genuinely couldn't tell what you meant by "highest level." (I was picturing a food chain, where big clouds of debris "eat" smaller satellites in their way.)

[1] https://www.sciencedirect.com/science/article/pii/S092180092...