Now, one good answer to "could deliberately induced Kessler Syndrome stop ICBMs?" is that the amount of mass required for such a thing is in the realm of ~2.5 trillion kilograms of matter, which is multiple orders of magnitude larger then the total amount of mass humanity has put into orbit.

However, what if it wasn't humanity doing it?

Let's say that a self-replicating pseudo-Berserker probe enters the Sol system. Its objective is not to exterminate all life on Earth, or to terraform it, or to render it uninhabitable; instead (hence the "pseudo-" prefix), its modus operandi is to:

  • Create a series of local system-only tugboats and gravity tractor craft that redirect asteroids into the lowest possible stable orbit of worlds it deems to be habitable.

  • Mine these asteroids apart in order to self-replicate, refuel (after all, hydrogen matter-antimatter annihilation rockets require hydrogen as well as antihydrogen), and build more self-replicating probes, as well as several kilostructures (think of them as smaller versions of a megastructure) in the outer Solar System. The exact number of self-replicating probes and kilostructures built depends on the plot.

  • Disperse leftover/unutilized materials into a relatively dense orbital shell which covers the entire planet, so as to make it impossible for spaceflight or space travel to occur until laser broom technology is invented. This is a deliberate design choice by the probe's creators (ancient humans); they believed that one of many metrics by which a responsible civilization can be distinguished from an irresponsible one is their level of interest in developing and using anti-orbital debris technology. This has a side effect of stopping ICBMs, which are exposed to flying particles during their midcourse phase and are hit with high-velocity rocks and gravel, damaging them and rendering them incapable of delivering their payload.

  • Boost out of the system to construct more kilostructures and probes in other ones. Alpha Centauri is next.

In short, mass is really not a problem, because, from a writer's viewpoint, this thing can use as many asteroids as it needs to self-replicate, and its secondary goal is to make any orbital altitude inside a geosynchronous orbit impassable, at any inclination.

The question: with mass removed as a constraint, now is it possible for deliberately induced Kessler Syndrome to stop ICBMs, at least until laser broom technology is invented and rendered operational?

  • 3
    $\begingroup$ As an aside, even if Kessler syndrome stopped ICBMs, it wouldn't stop the nuclear-armed powers from switching the warheads into SLBMs (lower max altitude) or hypersonic cruise missiles. $\endgroup$ Commented Sep 8, 2021 at 4:49
  • $\begingroup$ @GrumpyYoungMan That's kind of what I'm counting on, actually. $\endgroup$
    Commented Sep 8, 2021 at 5:12
  • $\begingroup$ What stops someone from shooting down the station(s) running the show with something like a Saturn V and then picking away at the Kessler projectile net already in place with impact initiated nukes? Actually you don't even need munitions just fire up slugs using a ground-orbit cannon. $\endgroup$
    – Ash
    Commented Sep 8, 2021 at 5:52
  • $\begingroup$ @Ash This is approximately 750,000 years before the first fossil specimens of Homo Sapiens are dated to. Humans don't exist. $\endgroup$
    Commented Sep 8, 2021 at 5:59
  • $\begingroup$ @KEY_ABRADE Then whose ICBMs are they trying to block? The system won't stay stable over geological time, the moon and atmosphere will in fact pull it apart in a few years without correction, you'd need to keep putting mass in to top up the particle net are pieces fell out. $\endgroup$
    – Ash
    Commented Sep 8, 2021 at 6:07

2 Answers 2


You linked a good answer.

Will such a situation affect ICBM's - yes. (No)

Will it prevent delivery of pieceful(peaceful) freedom nukes - no.

  • I refer to that 5% percent chance, meaning 1/20 penetration, so as ICBM are not the only way to deliver, so as it is relatively easy to fix ICBM's to increase chances(changing delivery trajectories, using booster blocks, and keeping orbital trajectory within 300-400km)

Also do not forget, that this debris field will grind itself too. There is a 95% chance for the warhead to be hit in 20 minutes with a 7×12ft cross-section. A 100g piece of rock with a cross-section of about 16 cm2 (spherical shape, average density 2g/cm3) has the same 95% collision probability in about 75 days. (It takes about 5000 times longer than 20 minutes) - and that is for each such 100g particle.

So in about 2.5 months, 95% of your original particles hit each other (time is probably even shorter, but won't bother by that symmetry atm, not the point)

And due to collisions, they will be fractured into smaller particles and dust.

And that process of grinding is exactly what Kessler syndrome is, so your Kessler syndrome will experience Kessler syndrome. More particles more collision, smaller particles, and more of them. Grinding itself into dust.

And consequences of that are numerous(not the full list, or not that numerous).

  1. 95% fail rate easily converts back to 95% success rate. Dust is less effective in penetrating any exterior of warhead, basically for small particles, let say 0.1mm dimensions it does not necessarily penetrate 1mm of heatshield of warheads and other reinforcements they potentially have.

  2. Any collision is less probable at lower orbits 400km and below - so it will be your dust particle-free zone. (it is so even with the initial size, more on that is here https://worldbuilding.stackexchange.com/a/197027/20315 )

  3. A lot of that mass will deorbit, as not all dust made in a collision will continue to orbit. So the thing will thin out reducing its disruptive effectiveness.

The main point is - stuff which is so much effective as Kessler thing, is actually effective on itself and the processes we expect to happen, the evolution of that Kessler process, will go faster. And one of the processes is grinding itself, deorbit, become rings, and all that.

Kessler syndrome become a straw man thing, was presented as such boogeyman for the public and propelled by different authors as a convenient and flashy driver for their plots, self-convincing and self-reinforcing the notion without actually understanding the process and its aspects.

And I see some hundred's of thousand years in your comments, so presumably, that droid, which we are not looking for, is already departed and does not continue to supply matter to that debris field then there is no chance for it still being effective - it is long gone, and maybe can be detected by some smart scientists in some brain twisted chains of observations, but not noticeable for anything else.

But again, imagine it departed recently, and it was way more of that stuff a 100 years before that, and now the debris field is still strong. We invented ICBM's in less than a hundred years, that's why this 100y time frame. Do you seriously think guys designing those won't pay attention to the problem? Military guys won't make more of missiles if egg head guys won't figure something out? Make strategies which, rely on LEO trajectories? Etc etc.

Too many ways to fix a problem, and that Kessler trick is too cheap to solve anything in one sweet swipe. So as it is overrated by itself - as an obstruction for space, as the ways to remove it, etc. Guys, authors - work harder, do not be lazy - we aren't in the '70s for those cheap tricks to awe us or surprise or be funny. Any school-age human launches rockets and makes space programs in KSP, investigates war scenarios in Children of death earth - if they can, you can it too, lol. It will improve your understanding of things in many cases.

A world treaty looks way more effective solution - kinda works as for now, we are still not launching ICBM's left and right despite some tensions.


Sure but you run the risk of dimming the the sun with mining debris and possibly crashing the planetary ecology. If your mining throws off waste dust and excess material, especially if it is sulfur or carbon rich, that material has the potential to change the chemistry of the upper atmosphere. If you make one miscalculation it gets worse because you're going to have one or more unintended impact events on your hands, it would only take one half decent meteorite impact in the pacific ocean one to crash modern civilization irreparably.

  • $\begingroup$ The individual pieces don't need to be large to take out an ICBM; a 100-gram particle traveling at the ISS's orbital speed of 17,136 miles per hour hits with a force of ~2.934 megajoules, comparable to ~701.243 grams of TNT - and that's not counting the velocity it hits at relative to the ICBM it's impacting. An M-class asteroid is 5.32 grams per cubic centimeter. That's ~18.797 cubic centimeters of asteroid remains, or a sphere ~3.3 centimeters across. It probably won't block much light, and each individual object can be TINY and still very dangerous to an ICBM or space vehicle. $\endgroup$
    Commented Sep 8, 2021 at 5:03
  • $\begingroup$ @KEY_ABRADE The smaller you divide the chunks the more sunlight you block, smaller objects have a greater total surface area per unit mass. You were also talking about putting them into orbit in large pieces to mine them for construction material mess up one orbital insertion and you can kiss civilisation goodbye for a long time. $\endgroup$
    – Ash
    Commented Sep 8, 2021 at 5:06
  • $\begingroup$ I really doubt that there are enough particles to noticeably block out sunlight. I did address the "messing up orbital insertions" thing, though: the probe doesn't. This particular unit has been operating for the past 1.163 million Earth years, and the programming stored within it has been improved upon for approximately 10 million years. $\endgroup$
    Commented Sep 8, 2021 at 5:11
  • $\begingroup$ @KEY_ABRADE Sorry you're right I was working on Tonnes not kg, 2.3 Trillion kgs of material divided down to 100g particles is 23 trillion particles with a sun facing surface area of only 57,500 square kilometres, only enough to intercept 0.02% of the incoming light not just over 9%. A system in long operation that learns from it's mistakes doesn't stop something going wrong, no system is perfect and it would only take one mishap to defeat the purpose of the "not really a beserker" approach. $\endgroup$
    – Ash
    Commented Sep 8, 2021 at 5:43
  • $\begingroup$ @ash you may plug yours comment numbers into the answer. $\endgroup$
    – MolbOrg
    Commented Sep 8, 2021 at 9:44

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