The Swarm

Let's suppose we have a dyson swarm with an orbital trajectory analogous to the star-link constellation over earth, although only over a relatively small belt (lets say about 20 degrees from the equator) around the sun, producing in the ballpark of a few dozen exawatts. Obviously this would be a very thin swarm of satellites, as the sun is enormous and produces a truly incomprehensible amount of energy.

Each satellite is a massive kilometer-wide origami, a hexagon of polished foil bound to some supports. The mirror itself would be the primary reflector, focusing its light to a much smaller secondary reflector, a hexagon a few feet across, supported by extremely light struts that fold out as the mirror unfurls.

This focuses the light to a hole in the center of the primary reflector and out the back of the satellite. On the back is a tertiary reflector, which is a dynamically controlled phased-array lens, focusing the beam of light to a central collector satellite in a higher orbit, in a ring directly over the equator.

This outer ring is the collection ring, a few hundred kilometers over the mirrors, which orbit in a sort of squished torus. The collector satellites are, in comparison to the mirrors, very intricate, needing vast radiators to compensate for their pitiful efficiency and massive waste of heat.

The Method Of Operation

Now let's say we were a big bad terrorist organization that just wants the world to burn. Or let's suppose that the world has recently been freed from an evil imperialist autocracy, but they kinda want to make a comeback. (same evil autocracy that built those kind of dinky and underpowered long-haul ships)

If they wanted to cripple the solar system, or at least threaten to do so, what better way than to destroy or take control of the most critical piece of infrastructure? Easy! Just blow up the dyson swarm and in about a week, 19 billion people will be dying of starvation and civilization will be sent back to the early 20th century!

Currently, over earth, there is about ten thousand satellites orbiting earth at extremely varying speeds and angles, lots of which is space junk. A man by the name of Donald J Kessler proposed a serious future problem, called Kessler syndrome.

What if earths orbit becomes saturated enough that if a stray piece of debris hits a satellite, that satellite spews out enough debris to hit another, or two, or ten. Those satellites shoot out more debris, destroying more satellites. Eventually, earth orbit becomes a hellscape of flying debris, where no rocket can pass.

Humanity would be planet-bound, for the next thousand years or more, until the thin atmosphere in space causes all that junk to fall and burn up. What if we could make such a cascade happen in the dyson swarm?

The Weapon

The Kessler Swarm-destroying chaff bomb would be a bomb, possibly a nuclear one, possibly of some other, less destructive type, engineered to shoot out as much chaff as possible and trigger a Kessler Cascade, destroying the swarm mirrors, and clouding so much debris over its orbit that it is almost impossible to salvage.

I propose a nuclear weapon, possibly a pumped fusion warhead, surrounded in a blanket of liquid, possibly a non-ferrous metal. The weapon would explode, vaporizing some of it instantly and spewing tiny droplets at insane speeds. They solidify into tiny, impossibly plentiful bullets, moving at orbital speeds. (hundreds of thousands of kilometers per hour)

The debris would orbit around the sun, punching holes in the foil and destroying the phase-array control computers on each swarm mirror, or worse, causing a cascade of failures in that narrow belt of collector satellites over the top, punching holes in their big, delicate radiators and spewing off loads of debris.

The Question

How effective would this be? Would it even work?

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    $\begingroup$ Sam, please go read the wiki for the internal-consistency tag. A number of your Qs appear to favor that Q format. However, Please read the wiki carefully. You are required to meet specific conditions to avoid closure. But it's the tag that allows you to ask, "here's the relevant rules and a situation to test against those rules, am I being consistent?" One thing you do need to remember, there are limits to what that tag can do for Real Life. E.G., we don't know how to build dyson swarms, so we don't know how to disable them in Real Life. You need to provide your rules. $\endgroup$
    – JBH
    Jan 1, 2023 at 21:01
  • $\begingroup$ @JBH I don't understand what you mean... I should probably use the internal consistency tag on this question, but what do you mean about 'limits to what tags can do for real life'? (Ill add the tag in a sec) $\endgroup$ Jan 1, 2023 at 21:09
  • $\begingroup$ It'll make more sense after you're read the tag wiki. Here's the problem: you can't ask how something might realistically happen to a construction that can't be realistically built. We're creative, but we're not gods. For a question like that you need to provide all the technological explanations concerning construction so we can derive failure points. If you can't provide those explanations, we can't provide failure points. $\endgroup$
    – JBH
    Jan 1, 2023 at 21:33
  • $\begingroup$ @JBH Oh! Ok! I understand, and I will fix that! $\endgroup$ Jan 1, 2023 at 21:45
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    $\begingroup$ OK, we're getting a LOT closer, and I'm hoping you're willing to edit your question to narrow the focus. Specifically asking if the whipple shields as described will fail to create a Kesler cascade can be asked fundamentally independent of the time period for the question. I'd remove anything from the post that doesn't focus on that one (and only one) question. As for that large-scale orbital shrapnel bomb - if any such creature exists, given our present tech, it would be buried under layers of folders marked "top secret." I'm sure the answer is "nope." $\endgroup$
    – JBH
    Jan 2, 2023 at 22:33

3 Answers 3


Bullets don't work against bees.. use a sensible military strategy

Your dyson swarm consists of zillions of relatively unimportant components, floating far away in space on a few hundred kilometers distance from each other. When you disturb a cloud like that with a nuke as you describe, there will be damage and many sats bumped out of orbit, but the effect remains local, within a certain radius and the chance of collision is very limited. It would require an enormous amount of bombs to cover a relevant part of the Dyson's orbit, or cause a relevant Kessler effect.

As a military strategy, that is a no-go.

Hit the collectors

A better target will be the collectors. You don't have to destroy them, they just need to be bumped out of orbit. The collectors are far less in number, and closer to the planet. The proposed Kessler disaster would be closer and more dangerous.

Hit energy harvesters and energy transport facilities in orbit

Your question does not tell how the collector energy is harvested, but if there's a location somewhere inside the toroid swarm of collectors, on the planet, or in orbit around the planet, these may be even more plausible targets. Like your proposed Kessler disaster, it could have nasty consequences for the planet, when the collectors keep beaming energy in the direction of the planet, while the receivers and the energy transport system in orbit is destroyed.


You establish the initial conditions and trigger event for a Kessler syndrome then ask whether the Kessler syndrome can take place? Uh, sure, I guess?

Whether or not it is effective depends on the swarm satellites' mass and density of their orbital configuration. The initial trigger must spall off enough material to cause equal or greater spalling among other satellites to propel a runaway reaction. Otherwise, the destruction peters out.

I can't find a solid way to calculate the Kessler "tipping point" (maybe it could be modeled with percolation theory?). As the writer, you can just assert that this is the case (I can't build your Dyson swarm for you), that the satellites are massive and packed densely enough to cause the destructive feedback effect. Though, one wonders why the swarm builders ignored such an obvious failure mode.

  • $\begingroup$ Good point, and as an alternative, you could design a shaped charge, as you just need to saturate one singular orbital path to destroy every single collector and shut the entire swarm down... or possibly two or three if it was built redundantly... I guess its plausible enough, because after the debris from the collectors radiators (big and delicate plates of metal, built as efficiently (and thinly) as possible) percolates down the gravity well, they will tear holes in the mirrors below. At that point, cleanup would be literal hell. $\endgroup$ Jan 1, 2023 at 21:31
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    $\begingroup$ Debris won't "percolate inward", if anything, light pressure and the solar wind should gradually impel it outward. No force is acting to move it to a lower orbit. $\endgroup$
    – Cadence
    Jan 2, 2023 at 3:13
  • $\begingroup$ @Cadence behold, the Poynting-Robertson effect... "causes dust that is small enough to be affected by this drag, but too large to be blown away from the star by radiation pressure, to spiral slowly into the star. In the case of the Solar System, this can be thought of as affecting dust grains from 1 μm to 1 mm in diameter" $\endgroup$ Jan 2, 2023 at 14:52
  • $\begingroup$ @Cadence Also, collisions may steal orbital energy causing some particles to drop their periapsis and collide with objects "further down the gravity well". $\endgroup$
    – BMF
    Jan 2, 2023 at 17:01
  • $\begingroup$ @Cadence even for satellites at geostationary orbit, they still have a lifetime, and will eventually fall and burn up, over millions of years. This is because there is an extremely tiny amount of drag. The same effect would pull the bits of debris in towards the sun, as its atmosphere at that level would be dense enough to slowly turn the angular momentum into heat via friction, turning them into flaming bullets of death for any delicate tinfoil mirror $\endgroup$ Jan 2, 2023 at 18:05

A couple issues with your bomb as described:

First, nukes in space don't actually have the same sort of effect as they do in atmosphere. Most of the energy output of a nuclear weapon is as gamma and x-rays. The giant fireball and all-destroying shockwave that we all think of as a nuclear explosion are caused by those gamma and x-rays superheating the surrounding air. In space, you don't have the atmosphere to absorb the high-energy rays and turn it into a shockwave and thermal pulse, so you just have a massive pulse of radiation instead. Certainly effective at killing anyone within a very large distance, but less good at destroying physical structures.

And in any case, you don't want to use a giant explosion to disperse the projectiles, because you don't want them to fly off into a higher orbit or escape orbit completely.

Whatever stations are nearby when your nuke goes off are going to have a bad time, but any that aren't in line-of-sight are basically safe from that blast, and are only vulnerable to whatever shrapnel is released from the first stations. And since they're already in a similar orbit to those stations' debris, most of that debris is going to be moving away from them, and what's coming towards them might not be in any sort of similar orbit, or possibly not even stable ones, so if they survive that, then the danger drops off further.

Instead, you'd basically want to launch huge barrels of shrapnel into similar orbits as the collectors but in the opposite/retrograde direction, and then give them just enough energy to disperse that shrapnel into a wide band.

The end result would basically be a massive grapeshot blast hitting the stations at effectively twice their orbital velocity, with any projectiles that don't hit the first stations staying in their opposing orbit. Each station would then have to pass through the projectile cloud twice each orbit, increasing the likelihood of hits and additional damage on already-wrecked stations. The debris from those stations would also accumulate, which will cause merry hell for any recovery operations, but for similar reasons to what I mentioned above, that's going to be somewhat less of a factor to the stations themselves.

  • $\begingroup$ The OP states that the nuke is surrounded by a blanket of something, which forms the cloud of projectiles. The average velocity of the cloud depends on the thickness of the blanket and the power of the nuke, and so can be tailored to deliver enough projectiles into a sufficient number of interesting orbits to do the needful. $\endgroup$ Jan 2, 2023 at 14:55
  • $\begingroup$ @StarfishPrime exactly. And when I mentioned a shaped charge in the other comments, I was thinking of a big, nuclear powered shotgun that could saturate the orbital path of the collector stations. $\endgroup$ Jan 2, 2023 at 17:59
  • $\begingroup$ This would be a fantastic "mutual assured destruction" tool for negotiation. No political faction in their right mind would ever dare to attack the dyson swarm, because it would mean everyone looses, so it wouldn't have to be built to resist intentional attack. $\endgroup$ Jan 2, 2023 at 18:10
  • $\begingroup$ But a terrorist organization whose goal is just that, mutual assured destruction, could have an ace up their sleeve to negotiate against every faction whose depended on it. $\endgroup$ Jan 2, 2023 at 18:11
  • $\begingroup$ Thanks for the idea! $\endgroup$ Jan 2, 2023 at 18:11

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