I don't know if this is more appropriate for /sci/ or /

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I'm no expert, but I've got a basic grasp on how current body armor works and the fundamentals behind them. Hard plates are meant to shatter bullets on impact and prevent penetration. Ceramic plates are meant for the bullet to penetrate it and lose force by resistance as it goes.

Q1: Assuming we make perfectly hard, indestructible armor - say carbon nanotubes and buckypaper is a complete success and we can make nice armors out of it, that somehow doesn't degrade - the force translated to the body should be about equal (less after air friction, etc.) to the recoil of the gun firing it, right? Except dispersed over the whole plate. The danger then is just the collision and how violent it moves you.

So using some pleb-tier collision math (and fault me if I'm wrong, v2 = [(m1)/(m1+m2)]*v1), getting hit by a 5g bullet at 900 m/s moves you (with gear) a scant .05 m/s. The earlier 7g iron meteorite at 12,000 mps moves you 1 m/s, kind of like getting checked by a hockey player. And if one of the faster meteorites, moving at 71,000 m/s, then I'd imagine it'd feel like getting hit by a small car moving at 14 mph. However, it doesn't take much more mass for even this armor to be inefficient. A small 100g meteorite at 12k m/s hits you like a car at 33mph, and at 71k m/s you'll be creamed like a car at nearly 200 mph. And at a single kg, you're going to wish it punched through you instead.

Now it's my understanding you can break this force down with padding - spreading the force out over more distance, like the hard foam in bike helmets or ceramic ballistic plates. To my understanding, allowing it to accelerate/decelerate you over time instead of suddenly. So,

Q2, does this effect have a significant/exponential effect to the extent of being able to survive these kinds of forces, or would it require too much space to work on a personal level (IE the crush space for a car).

Increasing your mass has the most significant effect that I can tell. Double mass is moved half speed.

>>32865663
Look into the work of Dr. Afsaneh Rabiei
Metallic foam is a bloody game changer for ppe development.

>>32865760
It's the same problem though. We're getting better and better at "catching" high and even hypervelocity projectiles. The problem stems from the fact that once you catch them, you're also catching all of their force. The force behind a small bullet at 900 m/s is nothing. If you catch it, it'll move a 90kg man only .05 m/s backwards. But if it was moving at 12,000 m/s? That's a bit rougher. If it was moving 71,000 m/s? That's going to do damage, assuming you caught it at all. And space has more than just 5g or 7g meteorites flying around.

My eventual goal is to keep someone alive through that.

You've got kinetic energy and you've got momentum. Neither one paints the entire picture; you've got to look at both. Like a rifle exerts a force over the length of the barrel to accelerate the bullet, having a means of energy absorption reduces the impulse and acceleration. Look into TRIP/TWIP steels or YSZ ceramics for some interesting materials perspectives on this. Having some multilayered brittle blunting - ductile energy absorption is important for penetration preventing.

Look into some of the passive and active defense systems on tanks; angled armor, explosive armor, active protection (iron fist or something), etc.

>>32865651
No. But we are still on 4xhan, so we are nerds.

Make it Star Wars or at a minimum Star Trek and we will jump on it.

>>32865977
Hyper velocity impacts are complicated and the fact is that you can't really armor spacesuits against them.

>>32865651
wait for materials science to catch up.

a company is selling carbon nanotube armor now.

>>32866001
Me

Oh, and once you get into some of these >5 miles/sec velocities, you are in the region where shit is no longer going to react as you may expect from extrapolating from lower velocities. The more applicable comparison for this is EFPs (explosively formed projectiles), where the penetration is measured in feet of steel.

>>32865977
well, a lot of meteorites are metallic, right?

if so, why not just set up a huuuge ass magnet outside your space habitat to deflect the meteorite?

or, why not track these things before they hit (i'm not 100% on the minimum size we can track currently, i'm pretty sure it's something like an object the size of a bolt over multiple passes) and hit them with a laser or something?

i dunno man. it just seems like if you can't take the projectile directly, you should deflect it ASAP.

>>32865651
spaced armor?

surround the ISS with floating buoys, possibly attached to the mothership somehow, with like a metal rod.

also look up the carbon nanotube armor

>>32865651
>The ISS is a fucking fortress of our best materials
If by thin aluminium shell, Kevlar and a lot of insulation then yeah.
A fleck of paint moving at orbital speeds has insane kinetic energy, like more than any artillery or vehicle mounted gun ever. But most of the time IF (I mean in the astronomical chance a fleck of paint hits the ISS) a super sanic fleck of paint hits the ISS they generally fly right through it and the self sealing layers have no problem sealing the micro hole it leaves.

The big problem right now isn't the extremely fast paint flecks it's the small pieces of metal from failed or problematic separations that haven't fallen back to earth and weigh up to a kg and are moving as like 12km/s, those are the ones that are a huge issue. But they're extremely rare and you have to remember space is fucking huge even right outside Earth. All the "space debris" on the space debris maps you see are separated by near city sized distances or more.

>>32866077
>the fact is that you can't really armor spacesuits against them
That's the premise of the thread though. As >>32866087 implied, within our lifetime we will be able to catch hypervelocity projectiles on a personal level. That much is obvious. The picture in the OP is the result of 1cm steel ball fired at a replica wall of the ISS at the speeds typical to meteorites. The ball was completely disintegrated in the impact, and the pictured ball is another one just there for reference, but we caught it. And the materials we already have today are so much better than what we had then.

The problem then is what happens after you catch it. And honestly, I'm hoping there's another way than just increasing the mass of the person, IE really, really heavy armor. A man in 1000kg suit would feel that same impact from the OP as an unarmored man would feel the recoil from a single shot of a powerful rifle. But 1000kg suits are not practical.

Spaced composite armor is the best

Lots of high hardness steel plates with an airgap in-between them, backed up by a thick plate to catch anything that passes through. Then kevlar, then hull and insulation.

You design your station modular, so you can bolt on the armor in space.

It's easy to protect against as the projectiles are so low mass.

>>32866223
There's no way to dissipate that amount of kinetic energy reasonably.

Like you pointed out, if you can armor an astronaut to the point where he/she isn't cut in half by the thing, they'd be flung out into space at insane speeds and salsa'd by the acceleration inside their suit anyways.

>>32866242
>You design your station modular, so you can bolt on the armor in space.

This also allows you to replace damaged armor portions that have been hit one too many times.

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>>32866219

>fly right through

thats... not how it works.

the iss has spaced armor on the areas most likely to be hit. for bigger stuff that can be tracked, they move out of the way.

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>>32866219
>If by thin aluminium shell, Kevlar and a lot of insulation then yeah.
There's more than that; they use ceramics as well. And the kevlar composite they use outside the aluminum shell is orders of magnitude greater than any equivalent here on earth. To quote on it, "Even the most powerful sniper rifles on Earth wouldn’t be able to blast their way through Kevlar in the same way." Referring to the test on pic related, which successfuly prevented any harm from the aluminum shell beneath it by a 7.5mm bullet fired at 7,000 m/s.

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>>32866292
No, you're totally right I wrote that completely wrong sorry lol two sentences that were never meant to be together.

>>32866315
Heat shield's on the outside, obviously. It's ceramic but it's not the same ceramics used in body armor on vehicles or SAPI plates.

I skipped most of this wall of text, but look into graphene, that shit is the future

>>32866360
Have fun making more than 1kg/year.

As far as I know the only reliable way to manufacture it en masse right now is by using a lot of CD drives. As in the one (maybe) in your computer, and in extremely thin layers.

>>32866371
How we make it now is completely irrelevant. That's like looking at the construction of a computer 80 years ago and saying, "Have fun ever doing more than this."

It's the same for buckypaper. Yeah, the process is stupid for how little you get. Years from now, as we get increasingly more efficient methods of forming and shaping carbon nanotubes, production is going to be entirely different.

>>32866422
Never said we wouldn't be able to make enough.

The ISS will be decommissioned by the time we manufacture enough.

By that time space efforts will most likely be towards Mars which has a whole other set of problems.

>>32865651
realistically?

make it cheaper to lift more weight.

>>32866484
>The ISS will be decommissioned by the time we manufacture enough.
On a side note, I doubt that. I don't know when NASA will finish designing a new, more efficient shuttle, but it should be within the next decade or two. And the ISS isn't a matter of is-or-isn't. As our technology progresses, I expect we will begin replacing the individual units with more advanced modules. Better wells, better electrics, better security, better utility. It's a hub, and so long as we persist into space, we're going to need one.

Unless I'm thinking of something else, the ISS should - and was built to - always progress with us, composed of interchangeable units that can be upgraded.

>>32865977
Magnetically shaped iron plasma force field with net positive charge of at least 25Mw and a shield radius twelve inch minimum thickness will vaporize any material known to man up to 15g moving at speeds up to 80,000m/s. It's not yet manned portable though.

In fact, it doesn't even exist and I was never here.

>implying anyone would believe anon is posting ECI on a Japanese macaroni sculpture website.

>>32866562
>up to 15g
That's not very helpful, sempai. In the math I did earlier, catching even a 100g projectile at 71,000 m/s still isn't within lethal levels, without any further protection than a hard plate welded onto your skin. Assuming hard foam, or as another anon mentioned metallic foam, padding to dissipate energy over space, that's even less an issue.

>>32865977
I don't see any other way it could work. Something's not going to hit you and roll right off or get deflected in another direction without some force being absorbed.

What if the answer isn't armor but a system that quickly detects incoming debris and moves the subject out of the way before impact?

>>32866585
>>32866562
Oh wait, the 100g/71k m/s was the first step into lethal levels. Still, adding some mass and adding some padding both mitigate it significantly.

>>32865651
>I'm not a gun expert, but google says a bullet is about 5-15 grams and is fired at 900 to 1500 meters a second? And our current body armors cannot even ensure against the higher calibers of those statistics.
ESAPI (or maybe XSAPI?) ceramic plates can withstand a minimum of 3 (i think) .30-06 armor piercing rounds

>>32866604
How heavy and how fast are .30-06 armor piercing rounds? Just out of curiosity.

>>32866612
nosler claims 110 grains at 3,400 feet per second

>>32866625
So 7g at 1050 m/s. Pretty middle-ground to the statistics I gave.

Neat though. I didn't know what parameters armor piercing rounds were within. Thank you.

>>32866640
.30-06 AP is 150 grains or so at 2,800 FPS

>>32866545
Yes but it's a bad idea to have just one big interconnected station like that, if it fails catastrophically all is lost. Makes more sense to have a LEO base for utility and fuel storage as a jump off point to a station further out in a geosynchronous transfer polar orbit coinciding with the heliocentric orbit of the earth to facilitate easy transfers to other planets while avoiding the Van Allen belts.

>>32865651
you're underestimating the vastness of space

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Simple problem with no simple solution. How do you prevent damage from high energy projectiles? You have a few options:

1. Armor that absorbs the impact. This is fine for vehicles and immobile structures, but not ideal for personnel since the amount of armor required restricts movement, though the weight factor is less of an issue in space obviously. You have to replace them as they get damaged, but that's not so bad. Hard armor could possibly be replaced by some sort of force field, plasma or otherwise. I don't know shit about that.

2. Slow down the projectile. Essentially drain its energy by making it travel through an easily replaceable substance like foam. Or maybe in the future we will have space-time dilators that do the same thing to space locally that a large body does.

3. Avoid the projectile. Not really feasible, unless some future technology allows the spontaneous opening of worm holes. Even then, you have to see the little shits coming.

4. Destroy them before impact. You could hit the projectiles with an equal or greater force, potentially with an automated turret.

Don't read this I'm drunk

As others have pointed out, hypervelocity impacts do not behave anywhere near the same as low velocity ones do. What spacecraft use is something called whipple shields, >>32866292 already posted a pic of them and how they work, and the ISS that >>32866343 shows is covered in them.

When you add on top the issue of changing your own velocity in space and the requirement for mass to be as low as possible, you can see why present day armour plates are not feasible.

>>32866219
Flecks of paint don't have enough mass to do that kind of damage even at ludicrous speed.

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>>32867067
Not him, but as mentioned in the OP, flecks the size of grains of sand or smaller sandblast the shit out of stuff. The small pocks on this lunar rock are the result of those tiny particles hitting at that speed.

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>>32865651
I have an inflation fetish so my first thought was to use a round inflatable space suit to surround the astronaut. Inflatable rooms and shielding are already used in outer space and are supposedly strong for their light weight. So transferring it to a person isn't too much of a leap. But such a system would restrict mobility, seriously limiting what the astronaut could do.

So I think a better solution would be to use an external balloon as an inflatable shield. The balloon could be large enough, as large really as you need it to be, to absorb the impacts while protecting the wearer. The astronaut could wear it like a backpack, leaving their arms and legs free to grip ladders or manipulate equipment.

Upon reflection I realized this space balloon would be a space age update of the samurai horo, a silk cloak/parachute that was used to guard against arrow fire.

https://en.wikipedia.org/wiki/Horo_(cloak)

https://www.youtube.com/watch?v=8B_6BU7SYf8

How to detect all incoming meteorites would probably be an easier problem to solve with current science.

>>32866841

They behave similar

The Whipple Shield is the same as any spaced armor array -- the thin side skirts on the Panther tank did the same thing -- they induced yaw on the projectile so when it impacts the main armor it doesn't penetrate nearly as far. More layers of plates + air = less overall penetration.

Stuff in space is lighter and faster for most impacts, so once it perforates a plate, it expands rapidly, greatly reducing its overall penetration against a monolith block (like your hull or main armor).

It's the same science.

Like someone else said, modular armor blocks (spaced plates with a heavy backplate) is a smart idea, which allows you to save weight.

>>32867565
I'm not sure how they work since the lower density of air compared to steel will bounce and deflect a projectile when the projectile exits the side skirt of a tank.

I'm not sure about space, drawing a comparison from optics and Snells law, Space has an n of 0 where Steel has an n of whatever.
Though, it's not optics, I'm not sure if it would work in the same manner.

>>32867537
My bad for double post.
Trying to detect all the space debris would be like trying to map the sky with radar quite literally. In fact most of what you want to filter OUT is all the space debris when using radar. Obviously NASA detects larger objects via radar but it is extremely hard to detect every object via radar as most of it comes back around the noise threshold of your antenna.

It's also worth pointing out NASA alone can only monitor something like 5% of the night sky for objects about to smash straight into earth. So by the time we knew about a few hundred meter diameter meteor moving at insane speeds towards us it will most likely be too late to do anything about it in many cases. The same can be said about space junk, however because it's more or less static in its path its easier because once you find it you can put it on a map and let the computer calculate its path after that and no longer have to monitor it actively.

Short answer no not really, it's not an option to monitor every object in space. It would be ideal, but not feasible for the time being.

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>>32867594

>>32867695
Loved that show, so comfy with an exciting twist towards the end.

>that chink spacecraft finally fragments
>debris cascade turns all the orbital boddies into a cloud of tiny pieces
>the cloud wrecks satellites, everyone looses GPS, missiles have to be triangulated from the ground

>>32867715
we probably should have some high pressure gas guns ready somewhere to shoot debris back to earth with in case shit like Kessler syndrome actually happens....

>>32866806
Sweden YES!

>>32867715
But if it fragmented, why would the particles pick up speed enough to hit any of the other satellites moving at the same speed as it?

If it sped up enough to catch up to the other satellites, how has it not broken from geosynchronous altitude and missed them by kilometers?

I've never understood this theory. Geosynchronous orbit means maintain a very specific speed at a very specific altitude. Any deviation in speed immediately causes the orbiting object to begin plummeting towards earth (if it slowed) or further and further out into space (if it sped up). Something can smash up a few satellites in passing, but those satellites will very swiftly leave geosynchronous orbit - only a few particles will maintain their original speed and orbit, which won't catch up to other satellites as they move at the same speed.

>>32867782
perhaps if we pushed some of the larger debris out of orbit

but when we put anything up, it's at risk of damage because of space junk

I remember hearing how the international space station got sandblasted by orbital particles

things we think are miles away still collide every now and then

but what else could we do

>>32867820
by understanding is that when something in orbit explodes, most of it falls out of orbit, but there is so much deris created that some of it stays in orbit just by chance

one dense object, becomes a massive cloud of the tiny particles that stayed in orbit

>>32865663
>the force translated to the body should be about equal (less after air friction, etc.) to the recoil of the gun firing it, right?


Nope.

A force is a measure of how two things interact, in this case bullet and target, or on the other end, bullet-gun-shooter. Since the interactions are different, the forces end up being different.

As these interactions are quite complex, dynamic events, you're not really going to calculate the forces anywhere with less than a full computer simulation either. On the other hand, it's also often not the relevant thing to look at here. You're probably going to be looking at things like impact toughness vs kinetic energy with some kind of penetrator efficiency number thrown in. Focusing on force excessively is, I'm afraid to say, often a sign that someone doesn't know his physics properly.

>So using some pleb-tier collision math (and fault me if I'm wrong, v2 = [(m1)/(m1+m2)]*v1), getting hit by a 5g bullet at 900 m/s moves you (with gear) a scant .05 m/s

Nope. Kinetic energy is not a conserved property, and it isn't a vector property, so nature wouldn't know which way to move the target anyway if that was all there was to it. To look at impacts moving things around you start at the momentum (the directional, conserved property), trying to do the math here without the momentum drops you from "pleb tier" to "four year old with a pot on his head thinking he's a Navy seal tier".

>>32867840
but that just means that you will have a cloud of particles with roughly the same position for a short time, but they will turn into a ring of sorts over long periods of time.

if you want to put a satellite in the same position as the one that exploded just check the position for no pieces of debris larger than, say, a fist, and launch it up a year or two later.

>>32867840
Right, but if it's in orbit, it must have a specific speed relative to a specific altitude. It cannot hit other orbjects also in orbit (for example, most satellites are in geostationary/geosynchronous orbit (at a specific speed exactly 35,786 kilometres above earth) that exact sweet spot in altitude allows an orbit at the rotational speed of the earth, so you remain above the same spot on the ground always. You can maintain orbit at lower or higher altitudes, but they will not be geosynchronous, but you cannot maintain orbit at the same altitude with higher or lower speeds.

In other words, there is no way for there to be an impact. An object in orbit cannot catch up to other objects in orbit at the same altitude. All objects in orbit at different speeds must be at higher or lower altidues, thus also out of the way.

They only way for an object to hit another is for the offender to start at a lower orbit, pick up speed (leaving orbit), and move further and further out with each revolution until it finds a new orbit or leaves - or for a higher orbit object to begin decelerating and also cross paths at one exact point with the geosynchrnous altitude for one short moment and plummeting below that as well.

>>32867827
>perhaps if we pushed some of the larger debris out of orbit
Nah, I was thinking sending everything down to earth where it can burn up on reentry. every piece that falls back matters.

>but when we put anything up, it's at risk of damage because of space junk

I was thinking about having it somewhere between the moon and earth where it would be relatively safe...

>but what else could we do

MAGNETS!

>>32867840
For example, to move a satellite out of geosynchronous orbit to graveyard orbit, all we do is accellerate the orbiting speed of that satellite 11 m/s, which puts it a good 300 kilometers above geosynchronous orbit.

In other words, a satellite being hit and speeding up a mere 11 m/s quickly leaves its altitude with other satellites and enters a higher orbit. 11 m/s is nothing, hardly even a danger if it caught up and hit something, yet it will swiftly move kilometers above the other orbiting satellites, not endangering them.

>>32867885
I think something large in low orbit that blows up, could accelerate smaller pieces into a higher orbit

but I'm not an educated man, I would only be guessing

I think the geo-syncronous orbit is actually part of the risk
if the orbit of one object deviates, it could hit other geo-sycnronous ojjects
thereby the relatively static group of orbital bodies could become a cloud

most of it wouldn't be in a perfect orbit, and would arc out or burn up sooner or later, but in high orbit this could take thousands of years

>>32867904
somehow I don't think it's so neat
things would be falling down and being flung up all the time as this debris collides with it'self

if a satellite was hit, it might accelerate upwards
but it a piece detatched from it, that piece would stay in the clear zone until the tiny force of drag pulled it down

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>>32867966
I actually looked this up since my last post. The issue is due to asynchronous orbits. Same altitude, same speed, perpendicular orbits.

I didn't think we had done anything so stupid until I remembered Russians exist.

>>32867966
>>32867973
And to add to the 2009 collision, the deactivated Russian sattelite was low enough that it still experienced drag from the very small presence of atmosphere. Normally that isn't an issue as it would just continue gradually lowering orbit for years upon years, since it has no propulsion system, but improperly tracked plus degrading orbit = eventual collision with the thing that's traveling fucking perpendicular with it.

Fucking Russians.

>>32867973
you think that is bad

https://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_missile_test

Chinese fired a kinetic projectile into space, and used a defunct satelite as a target
threw shit everywhere

and there was a US test of an anti-satelite weapon in 2008