[to11mtm]

"Low" is tough to say until someone does some proper sort of 'true mapping' of space debris in the range somehow. Protection would require a lot of complexity and cost due to the need for shielding and the delta-v to move it up there.

[JumpCrisscross]

> until someone does some proper sort of 'true mapping' of space debris in the range somehow

You look at which satellites poofed and then figure out the maximum extent their debris could have drifted.

[mapt]

That works a little bit when we're talking about one satellite poofing in a year based on a collision with another satellite, and not at all when we're talking about thousands of events a year, many of which are satellite-debris collisions too small to track (you only get one orbital vector), or between pieces of debris.

Every collision generates hundreds, maybe thousands of pieces of debris, only the largest of which are trackable.

[JumpCrisscross]

Not really. There are uncertainty bands. But based on the collision you know which orbits are spoiled for about how long.

[vlovich123]

Rather than protection on each rocket, couldn't you just send a bunch of fortified rockets that absorb the debris during a collision but don't emit anything. Do that a few times and then all other rockets just reuse the path that was cut?

[mapt]

Orbit is not a location. Orbit is a group of velocity-location vectors which form a stable loop around a body, without intersecting that body.

Imagine a bullet circling your head at mach 25. Now imagine a second bullet, circling your head at a slightly different angle, at a slightly different distance from your head. There's a chance that they could collide, and the resulting explosion would leave a great deal of dust... on a mixture of velocities, still circling your head. Now add a third bullet, also on a slightly different vector; Make sure that it doesn't collide with any of that dust!

The actual situation is we aren't dealing with 3 bullets or 100 bullets, we have ~170 million objects orbiting the Earth, and only around 50,000 are large enough to track. They are all moving fast enough in relation to each other that a collision would result in a sizable explosion, not an elastic agglomeration. We have no way of removing them.

The good news is that there is a large volume of space for them to exist in. The bad news is that as we continue to fill it up, odds of collisions increase, and every collision spawns many, many more objects.

[vlovich123]

You’ve explained what Kessler syndrome is but not why my idea doesn’t work.

I’m saying send reinforced rockets through the orbits that absorb the collision instead of generating more dust. That should let you clear a path through all orbits that intersect your path. It’s hard to do and the 3d aspect of it might make it expensive but conceptually it could be a solution. Or use super powerful lasers (potentially mounted on a satellite) to deorbit the dust

[ben_w]

> I’m saying send reinforced rockets through the orbits that absorb the collision instead of generating more dust. That should let you clear a path through all orbits that intersect your path.

No such material exists, nor can it be made from any matter that is based on electrons bound around a nucleus — the force of impact will break any such material.

> It’s hard to do and the 3d aspect of it might make it expensive but conceptually it could be a solution.

"expensive but conceptually it could be a solution" is also why we don't have an Orbital Ring instead of rockets: https://en.wikipedia.org/wiki/Orbital_ring

The cost requirement for getting something to space with enough momentum to do the cleanup, even if it was able to survive the impacts, would be comparable to the entire cost of getting the stuff constituting the mess into orbit in the first place: bad enough to be prohibitive even today with relatively little mess, much worse if there's an actual Kessler cascade.

> Or use super powerful lasers (potentially mounted on a satellite) to deorbit the dust

Could work for the bigger bits, but don't put the lasers on a satellite: 1) Power is short up there, as is cooling, much easier to put a bit laser on the ground and waste some energy going up through the atmosphere; 2) if you solve that constraint, you've now got an orbital laser that's an obvious and easy-to-hit target for all foreign powers to get upset about even if you didn't want to weaponise it.

For the smaller stuff, you can't see the dust to target it in the first place.

[mapt]

This doesn't work conceptually, but it's hard to explain without attaining a KSP baseline of understanding. https://xkcd.com/1356

"Clearing a path" is something you can do with a bulldozer through a traffic jam, but imagine clearing a path through a belt road by driving through the flow of moving traffic sideways at speed. Ultimately you can't hit every car in the outer lane with just one bulldozer, and the cars will close in and fill gaps because they're moving at slightly different speeds.

The easy elastic collisions you're imagining also just can't occur at these relative velocities. When something hits it looks more like an explosion than a "catch". If you shoot a local stone monument with high explosive artillery shells what happens? Does it reduce the number of things flying through the air or increase it?

[immibis]

It takes about 90 minutes to complete a low earth orbit. A rocket can't hover in place for 90 minutes at the same altitude, then increase its altitude by its height and repeat. It doesn't have enough fuel for that.

[vlovich123]

Go the other way. Attain maximum altitude and then descend slowly. You don’t need to do this with just one rocket. This would be a clearing exercise composed of multiple rockets.

[LoganDark]

This sounds like it would almost work in a 2D universe.

[lmm]

> couldn't you just send a bunch of fortified rockets that absorb the debris during a collision but don't emit anything.

"Just" how? Orbital collisions happen at an average of 10km/s, you're going to make what, some kind of sponge that can get hit by a chunk of satellite going ~8x faster than a bullet and absorb it and slow it to a halt without fragmenting at all? Good luck.

> Do that a few times and then all other rockets just reuse the path that was cut?

Things in orbit are constantly moving, you can't "clear a path" any more than you can, IDK, make a safe route through a forest by walking through it once and moving any bears you encounter a couple of feet.

[lupusreal]

A large mass of Whipple shields.

The "clearing a path" idea is inane, but we do know how to absorb hypervelocity debris impacts while generating a net negative amount of debris.

[ben_w]

Whipple shields fragment, don't they? They slow stuff down enough to not be a hazard to the thing being shielded, but if the goal is mess-reduction I don't see how that will help?

https://www.researchgate.net/figure/Whipple-shield-concept_f...

[lupusreal]

The force of the impact effectively vaporizes part of the shield and the debris. Eventually the shield will be structurally unstable swiss cheese, but that can be modeled and the shield deorbited before it starts to fall apart.

[RHSman2]

I love this retort. Made my day.