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Comment by killjoywashere | Hacker News Reader

Is this a solvable problem? Can you launch a steel plate of 8000 kg and attach thrusters to it, and drive it into known objects? Occasionally refuel the thruster module. I'm guessing a 1/2" steel will absorb some pretty significant energy. Make it 1" steel in the vicinity of the guidance thruster system. Have a plan to deorbit the steel in sections. It's essentially a filtration system.

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Huge blocks aren't actually the best way to destroy projectiles with that much energy, monolithic shields will tend to spall material off their back side and even small pieces will deal massive damage. Wipple shields are more effective because the debris are shattered by the initial layer and as a result the energy is spread out a lot more when it hits the subsequent layers.

The problem is you need to destroy more debris than you create with your shield.

https://www.technobyte.org/wp-content/uploads/2017/05/How-do...

1/2 oz piece of plastic into Al at 15k mph: https://external-preview.redd.it/oi0C_a113_sSzHtSaPvzn6_0Gfg...

Im skeptical this would work for anything bigger than paint flakes and possibly some very small fragments the size of tiny bolts.

The thing is at orbital speeds colisions are VERY energetic events that don't behave likey normal low speed collisions. The thing coliding effectively turn into rapidly expanding plasma before any of the expected plastic deformation, shearing, etc. one would expect on a low speed collision (say a truck in full speed hotting a wall).

When you think about it, this effectively all the fuel and oxydizer that has been used to place the given object into orbit releasing all it's energy at once in a very small area.

As an example let's say your steel plate manged to hit a 700 kg satellite at ~8 km/s, which is perfectly possible with, with the worst case being a 16 km/s combined in a head on collision. How much energy will get released ?

Say the sattelite has been put in orbit using thr Soyuz 2 launcher, which can accelerate up to 7000 kg to tje orbital speed of 8 km/s. Soyuz 2 weighs about 312 tons, more than 90% of which is fuel and oxydizer. It could launch 10 of our 700 kg satellites.

This effectively means a 700 ks sattelite hittimg your 8 ton steel plate is equivalent of a point detonation of ~30 tons of perfect mixture of liquid oxygen and kerosene.

I don't tging a 8 ton steel plate will survive that in any usable shape.

This isn't right at all, a lot of the energy from launch goes into 1) gravity 2) air resistance 3) accelerating the fuels to do 1 and 2. Only the actual mass and velocity of the satellite matter. It's a lot but it is very far from being equal to the whole mass of the rocket.

Indeed, it's definitely not 100% conversion of chemical to potential energy & speed, but given that we are talking hundreds of tons of very energetic chemicals, it's still a lot & IMHO still a nice visualization.

No, it's not even conversion efficiency of burning fuels, rockets expend a lot of their energy accelerating fuel that is later burned as well. That energy is not in the satellite when it's in orbit.

Yes, it's a very solvable problem. You just vaporize all the debris in your way and clear a path.

It's only unsolvable in the current context that a nuclear bomb going off in MEO or GEO is worse than some space trash. If the situation became dire enough that we couldn't get off the planet, then you could just detonate some high yield explosives in orbit.

Detonating a lot of nuclear devices in orbit would devastate large sections of the surface with EMP bursts as gamma rays ionize huge sections of the upper atmosphere.

https://en.wikipedia.org/wiki/High-altitude_nuclear_explosio...

Shoot. Great minds think alike. One note, you'd probably want to deflect hits into space rather than absorb them.

why not deflect them into the atmosphere to burn up?

Yeah, especially in LEO / MEO. In GEO towards space seems like a better bet though.

Though dead satellites in GEO make a lot more news.

It would be the world's largest ever game of Pong.

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