Even if these sats do collide and produce debris, they are in decaying orbits, so that stuff will eventually fall back down.

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dylan604 2 hours ago | parent [-]

Debris moves in 3D. Debris moving up will continue moving up. There is no force acting on it to bring it back down. Your comment makes it sound like an explosion would only be in 2D along the same orbit as the original object.

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KiwiJohnno 5 minutes ago | parent | next [-]

That is not how orbital mechanics work.

It may seem counterintuitive, but if something in orbit gets a push that isn’t strong enough to make it totally escape orbit, it will stay in a new elliptical orbit. That new orbit will pass through the point where the push happened, so it will come back through that location again, just with a different speed and direction.

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toast0 30 minutes ago | parent | prev [-]

> There is no force acting on it to bring it back down.

Gravity?

But also orbital dynamics (at least as I understand it) means debris that debris that is flung up is going to have a more oval orbit, so the high point (apogee) increases and the low point (perigee) decreases. And a lower perigee means more atmospheric drag, which will help deorbit the debris.

	▲	dylan604 9 minutes ago \| parent [-]
		That'd have to be one slow explosion to give it less than 1G of acceleration.