How about just a sacrificial shield well in front of the station along its orbital path?
and/or a weaker magnetic one, also further ahead (further ahead would allow for deflecting slightly at lower power surely).
Problem #2 - at those velocities, even puny bits of debris can punch through serious thicknesses of armor. (The "high velocity" shells that modern tanks use to kill each other are slow-pitch softballs by comparison.) And the "friendly fire shotgun blast" of debris created when a small piece of orbital junk goes through the shield can be far deadlier than that bit of junk would have been all by itself.
You’re not letting it pass through with an aerogel-backed whipple shield.
I wonder if you angled the whipple members you could preferentially deflect it at a high angle. That way it can carry most of its momentum away from the shield and the shielded station.
It’s also why being shot in a bullet proof vest with anything man portable doesn’t knock a person backwards (in real life), but gives them a heck of a bruise.
Without the vest, the bullet would go all the way through them, or create a huge wound cavity. [https://whitemountainforensic.com/wound-ballistics-motion-ef...]. Which is what causes the desired fatal effect.
Even when shot with something bigger (such as a tank round), there is no time for the momentum to transfer to their body without destroying it - for the same reason it is impossible to ‘throw’ an egg 20 yards by hitting it with a hammer.
These orbital debris are much much much faster than any known traditional bullets (17 km/s is 55,000 fps or 17x faster than the fastest common cartridge), so the effect is even more pronounced.
Interestingly, there was work by Newton that models these types of penetrations pretty well. They only start to apply to high speed bullet impacts around 3k+ FPS. The type of impact damage becomes noticably different then, with say 5.56/223 Remington on mild steel having an impact crater that looks remarkably like a asteroid impact crater at close range, but a normal ‘flat’ crater/dent at long range once the velocity has dropped significantly.
Once you past the speed of sound in the materials involved, it’s quite predictable based on the density of the material and the length of the projectile.
[https://en.m.wikipedia.org/wiki/Impact_depth]
It’s why modern tank penetrators are made of long, thin rods of high density material (such as depleted uranium or tungsten), and move very fast. They’ll penetrate essentially anything, with only depth varying based on density, because no material is able to transfer the force within itself effectively to ‘reject’ the penetration in time.
Spacing armor also helps, as it gives room for projectile fragments to break apart and lose energy over more area instead of efficiently transferring momentum directly into the point loaded part of the armor, which can dramatically reduce the impact depth in practice.
[https://en.m.wikipedia.org/wiki/Spaced_armour]
Angling the armor on the timescales involved in these impacts isn’t going to meaningfully deflect any penetrators though. It does, however, improve the effective depth of the armor. The forces involved in trying to redirect the later parts of the projectile based on the forces subjected to the first parts of the projectile don’t really work once you pass the speed of sound in the material.
[https://en.m.wikipedia.org/wiki/Sloped_armour]
Counter intuitive based on our normal life experience, but true.
So having many widely spaced layers of hard (to fragment the penetrator) then soft (to ‘catch’ fragments without transferring shock very well into later layers, hence spreading out the force over a wider area and often time) material in as ‘fluffy’ or an armor as possible is the most weight efficient way to stop very high speed projectiles - which is why it is used in space, because weight efficiency is really important.
Notably, heavier/denser versions of this (due to space constraints and the need to stop slower moving and heavier projectiles than in space) are widely used in newer generation main battle tanks in the form of chobham style composite armor. [https://en.m.wikipedia.org/wiki/Chobham_armour]
In those cases, sometimes adding explosives on top can help, as the penetration detonates it, and the resulting shockwave helps disrupt the projectile. [https://youtu.be/zK77-8kJ69c?si=PxMue9goABlfuiXY]
There are some neat videos of simulated tank armor penetrations on Youtube (look for “apfsds penetration test” for one example) that shows what is going on in pretty good fidelity.
So, to summarize - the aggregate force is not a real issue, it’s the damage done by the nature of the very high speed penetration. Think more ‘gamma radiation’, less ‘brick’.
Average adult males mass between 60-80kg, so such an impact - if fully absorbed - would contribute the momentum equivalent to a light shove to an adult human. Approx. 1/3 of a meter per second, or in American, about a foot per second of velocity. Barely enough to make someone shuffle their feet to stay upright.
Energy wise, however, it is the equivalent of approximately 34 grams of TNT [https://en.m.wikipedia.org/wiki/TNT_equivalent], or 2x 20mm Anzio Anti Tank rounds [https://en.m.wikipedia.org/wiki/Anzio_20mm_rifle], or 8x 50BMG rounds [https://youtu.be/fUOh7a0cdUw?si=xX7Qzdl5ZfUUIVOs] - at the muzzle.
Those cartridges are roughly the size of a medium carrot. Absurdly large by sport shooting standards.
YouTube 50BMG video is a bit gruesome btw (ballistic dummy), but no actual blood.
The 50BMG is the most powerful ‘one man portable’ weapon you’re going to find, as they typically weigh over 20 lbs, and firing it is a rather intense experience. Especially since very aggressive muzzle brakes are necessary if the gun isn’t anchored to something.
Armor to protect against it is so heavy, it is pretty much impossible to wear in field operations. Think ‘bomb suit’. It will penetrate armor on many modern armored personnel carriers. 20mm is far more powerful, even without explosive shells.
And that is the size and velocity of the ‘small’ orbital debris.
High-power thermal laser ablates a key portion of the space-junk to slightly change its trajectory and preferably help deorbit it. All you need is energy since the reaction-mass comes from the space-junk itself.
Maybe you could combine the ideas and instead of ablating to deorbit, you modify the space-junk orbits to collide with a large aerogel satellite. You could potentially even boost it in the process.
Why? If the Bit O'Junk is within ~90% of its apogee, and it hits the aerogel cube at more than ~90 degrees, the impact will yield a fatal drop in Mr. O'Junk's perigee. Ion thrusters on the cube-laying satellites, high-precision orbital tracking, and a few racks of computers on the ground (to calculate orbits and impacts) should be enough. Low-powered lasers would probably be useful in the precision-tracking systems.
Blasting space-junk with high-powered lasers is cool...but those immediately get into issues with dual-use, space weapons treaties, and arms race scenarios.
Can aerogel be manufactured by the satellite itself? That would be pretty cool. It also seems nearly as effective as a weapon though, a spy satellite with a camera or solar panels caked with aerogel is as good as destroyed.
It's not critical that the killsats produce actual aerogel. A little cloud of snow, from a water tank and squirt nozzle, could also work. What matters is that it's cheap, reliable, low-mass, soft-ish, and collides head on-ish with Bit O'Junk - cutting the latter's orbital velocity by a few hundred meters per second. Done near apogee, that'd drop Mr. O'Junk's perigee enough for atmospheric drag to finish him off in very short order.
Whipple shield [1]. You’d want it as close to the station to save mass because that’s how spheres work.
[1] https://www.daviddarling.info/encyclopedia/W/Whipple_shield....