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New Calculation Finds we are close to the Kessler Syndrome [video]

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Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#91

Post by mapt »

JumpCrisscross wrote: post #63
mapt wrote: post #57

Earlier quoted context omitted.

If 800km impacts go asymptotic, it pollutes 700km and 900km orbits by virtue of having a distribution of resulting debris velocity vectors, and as drag pulls down all the resulting debris over the next thousand years, the 800km debris becomes circular 700km debris, and then circular 600km debris, and then circular 500km debris.

> as drag pulls down all the resulting debris over the next thousand years, the 800km debris becomes circular 700km debris, and then circular 600km debris, and then circular 500km debris Circularisation isn’t the unexpected part. Sphericalisation is. One requires orbits to desync. The other requires plane changes.

Even in a purely planar distribution, nodal precession still occurs slowly.

It doesn't even need to be factored in, though, if different planes are colliding with each other and energetically generating a spectrum of new orbital vectors (many less than circular) from impact. This effect colludes with altitude drop from orbital decay and the tendency to circularize orbits by perigee drag, to make it so that higher orbit debris percolate into lower orbits over time.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#92

Post by [deleted] »

mapt wrote: post #8

The current trajectory is that SpaceX proved the commercial and military viability of an LEO megaconstellation, repeatedly lowering their target altitudes and raising their satellite count because of debris and cell size concerns... And now the rest of the world is trying to catch up in a sort of arms race, and not taking any care about debris concerns. The most tempting orbits are the ones in upper LEO that permit t…

[deleted]

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#93

Post by mapt »

vlovich123 wrote: post #62
mapt wrote: post #56

Earlier quoted context omitted.

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 dus…

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 mounte…

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?

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#94

Post by mapt »

nradov wrote: post #58
mapt wrote: post #48

Earlier quoted context omitted.

Invite them in. Launch their satellites for them, at 400km. Give them cash or territory. Give away the farm. How doesn't matter. What matters is that we start coexisting at 300-500km, and we mutually taboo launching large amounts to altitudes much higher than that. There is no stable Mutually Assured Destruction Nash equilibrium here, if either of us does this thing it causes dramatic harm to both. Not regarding that…

There is no world in which giving cash or territory to the Chinese Communist Party would be acceptable to US taxpayers, regardless of the consequences.

We've been doing it since Deng for the sake of making a few CEOs and shareholders richer. China operates or is monopsony sponsor of numerous pieces of infrastructure around the world in the name of trade.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#95

Post by mapt »

blackeyeblitzar wrote: post #61
mapt wrote: post #48

Earlier quoted context omitted.

Invite them in. Launch their satellites for them, at 400km. Give them cash or territory. Give away the farm. How doesn't matter. What matters is that we start coexisting at 300-500km, and we mutually taboo launching large amounts to altitudes much higher than that. There is no stable Mutually Assured Destruction Nash equilibrium here, if either of us does this thing it causes dramatic harm to both. Not regarding that…

[flagged]

It is trivial to retaliate in orbital disputes, and ASAT warfare produces long-lived hazard which cannot be cleaned up. Imagine two rival nuclear plants in nearby cities buying artillery and shelling each other, including with aerially deployed landmines.

Either you get along or you do not get to be a spacefaring civilization.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#97

Post by mapt »

tehjoker wrote: post #75
perihelions wrote: post #30

Earlier quoted context omitted.

Why would any of the US' adversaries agree to that? We have SpaceX, and they do not; lowering the altitude of megaconstellations is asymmetrically far more costly for them then it is for us. Stopping China's (highly strategic, military) satellite constellations isn't a "small amount of diplomacy". It's an impossibility. (It's even their declared planning that deliberate Kessler cascades are on the table [0]—to try to…

basically, it sounds like the U.S. should not treat China as a competitor and we should cooperate. this insane hypercompetition for literally no reason (other than US capitalists wanting to remain dominant) is going to destroy us all.

I make no claim about what we should do in other contexts, only that mutual destruction of access to orbit is so easy to achieve we're currently careening towards it full speed without what politicians perceive as 'open hostilities'. This particular domain requires an approach more like OPEC than like the Cold War, and the consequence of failure to collaborate is you never get to play around in orbit again.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#99

Post by RHSman2 »

lmm wrote: post #87
vlovich123 wrote: post #55

Earlier quoted context omitted.

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?

> 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 r…

I love this retort. Made my day.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#100

Post by fragmede »

lxgr wrote: post #65
ryankshaw wrote: post #29

Earlier quoted context omitted.

Is Kessler syndrome the Great Filter ( https://en.wikipedia.org/wiki/Great_Filter )? As in, is it the thing that makes it so no one else has broken out of their planet to come visit us? I could totally see it being the case that as soon as a civilization gets good enough at putting stuff into space, they start putting a lot of stuff into space and then things start crashing into each other to the point that they can’…

I'd consider it much less likely than e.g. nuclear or maybe chemical/biological warfare. Kessler syndrome (if even achievable with current technology) would be a major bummer for science and the global economy for a couple of decades (no more Starlink, but we still have good old geostationary satellites, so no ships and airplanes would get disconnected as a result), or at worst centuries, but would otherwise not form…

> if even achievable with current technology

Launching a nail bomb into orbit would've been possible as soon as we were able to get into space, the only question is motivation. A terrorist state, say North Korea, threaten the rest of the planet and demand concessions once they're able to get any significant mass into orbit.

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