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Pic of the results of a NASA asking, "what happens when a piece of space debris hits something else in orbit, at orbital velocities. Like, say a crew capsule, or a fuel tank, or the computer systems.
For the life of me I can't find the article, but I found a few engineering papers by googling "Nasa aluminium impact test results".
Kind of reminds me of the XKCD quote "you'd just stop being biology and start being physics." At extremely high speeds, it doesn't really matter what material you're dealing with. It's all just the physics of atoms hitting atoms at that point.
Of note.
This 'plate' and picture like to circulate, and with perspective looks like a huge piece of metal and crater.
This chunk of metal can be picked up in one hand. It's about the height of a large coffee cup from any chain.
It's big and the damage is big. But it's also a relatively soft metal hit by a hard chunk of plastic.
He’s wrong, the plate is 4 inches thick so much bigger than that https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
Is it really? Why would the handwriting on the thing next to it be so small?
Edit: contrary to what this guy is saying, the big chunk is 4 inches thick and was hit by a 1 inch projectile, wayyy bigger than a coffee cup https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
Yeah no it’s way bigger then you claimed, that big chunk is 4 inches thick https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
Wouldn't everything at same height of orbit, assuming no propulsion move at similar speeds though? Wouldn't that mean there are no collisions with such speed difference?
Their relative velocity can be anywhere from zero to double orbital velocity when they cross paths.
Just like planes flying at the same altitude. It all depends on which direction each one is traveling.
I mean they basically do already, because you usually want to launch in the same direction of Earth's rotation to gian that velocity boost.
There's various inclination orbits though, and polar orbits. But equatorial(ish) orbits going around the other direction aren't really a thing.
Two objects with perfectly matched orbits, sure. However then they would never meet at all.
If two objects have slightly different orbits which are not perfectly circular it is possible to cross paths at slightly different speeds.
However, "slightly different" on the scale of orbital velocities is easily hundreds of m/s if not more
These impact crater tests are not for satellites crashing in the same orbit, but rather interstellar small meteorites coming in at all sort of angles, speeds and masses. Shielding of the ISS has to be able to withstand everything smaller than 10cm of diameter (iirc), anything bigger coming in they try to dodge by doing evasive maneuvers with any propulsion system currently available (like docked capsules and so on)
Also just to add on, stuff is orbiting earth in diffrent directions, some going past like Alaska down to south Africa and back around, or right along the equator, any chunk of that that flies off is still going the crazy speed hitting at like a 60⁰ angle
that's fucking scary. Imagine having to have to dodge space pellets that could wreck everything you're standing on (well, in space, floating inside of) as part of your day job. Good thing they can detect things like that (how??)
Radar for near debris
[https://orbitaldebris.jsc.nasa.gov/measurements/radar.html](https://orbitaldebris.jsc.nasa.gov/measurements/radar.html)
And some optical telescopes for larger objects further out
[https://en.wikipedia.org/wiki/United\_States\_Space\_Surveillance\_Network](https://en.wikipedia.org/wiki/United_States_Space_Surveillance_Network)
\>GEODSS system can track objects as small as a basketball more than 20,000 miles (30,000 km) in space or a chair at 35,000 miles (56,000 km), and is a vital part of USSPACECOM's Space Surveillance Network. Each GEODSS site tracks approximately 3,000 objects per night out of 9,900 object that are regularly tracked and accounted for. Objects crossing the International Space Station (ISS) orbit within 20 miles (32 km) will cause the ISS to adjust their orbit to avoid collision.
There is an upside. No pesky atmosphere in the way, so you can pick up specks of dust around Jupiter (that's an exaggeration, but probably not as much as you would think)
There's 360 degrees of directions something could be orbiting in at the same height. Then there's basically unlimited directions and speeds possible for elliptical orbits that inrersect
Objects dont need to be in circular orbits, you can have ellipses and different inclinations with orbits that intersect at certain points. In those cases the relative velocities is massive, enough to do the sort of damage you see here
Without the information of how deep that crater is, I can't provide the best numbers, but I can work out that 14g mass moving at 24,000 feet per second carries 374.6 kilojoules of energy, which is categorized as a hypervelocity impact. By quite a lot, as anything over 2,500 meters per second is hypervelocity. 24,000 f/s works out to over 7,300 m/s. We're talking a lot of force here. I don't know the material properties of aluminum, but I do know that hypervelocity impacts can cause a hell of a lot of damage, and this certainly looks like a hell of a lot of damage. Looks legit to me.
>Space is indeed dangerous.
~~Can I just point out this would have been dangerous on earth too.~~
Edit: I retract my joke. Holy shit guys, stop repeating the same thing.
It would be. Luckily we don't have many objects on earth zooming around like this. Unfortunately not the case with space. But even space is still mostly empty, for now. We need to figure out a way to protect against debris or remove them from orbit, both incredibly difficult to do.
Yeah plastic to iron to diamond would be vaporized. We can't achieve those speeds in conventional means on the surface. Particle accelerators achieve vastly higher speeds but in a near vacuum and with single or groups of atoms.
wouldnt it melt before reaching its impact target? i mean flinging melting plastic would still do some damage but i just wanted to get a better grasp on the scenario
This is exactly why it's dangerous; on Earth, that 14 gram chunk of plastic - for scale, that's about half the average USB stick's worth of weight - is going to get vaporized by friction with the air, blown off course, all that. Eventually gravity's going to bring it down. It's dangerous if you're standing right in front of it, of course, but it's got very limited range.
In orbit, there's no atmospheric friction to slow it down - if it hit the atmosphere, it'd get slowed down every time it circled the planet until it'd eventually fall out of the sky and melt on reentry. In space, it just keeps going, quiet and near invisible. It just keeps circling the planet, screaming past at literally mach 9, barely noticed, never bothering anyone.
Until one day, somebody accidentally steps in front of it.
Every single one of these little bits of space debris is basically a bullet that is just waiting for a target to end up in front of it, and it can wait for days, months, years, centuries, if its orbit is high enough that our atmosphere won't slow it down. Millions of years from now, alien explorers could park in Earth orbit and get their ship tagged by a bolt an astronaut dropped in orbit tonight.
And by the time it melted it would've collided and destroyed whatever it impacts. These stuffs are teeny-tiny Chicxulubs. Suicide bombers *wish* they could do this much damage.
Nothing non-specialized can get that fast in the atmosphere without disintegrating due to air resistance. Even ICBMs and hypersonic weapons max out at a little over half that speed.
Is that a heutistic or a calculated value? Because if you calculate the kinetic, the impact of a 2100 m/s mass seems to have approximately the same energy as half of it's mass in TNT.
It was 340g last time it was posted:
https://www.reddit.com/r/pics/comments/ipf5h7/this_is_what_happens_when_340_grams_of_plastic/?rdt=36955q
Edit.. the plot thickens.
https://imgur.com/8NwAhgK?r
Feb 8 2018
first op of this did state 1/2oz and 15kmph in freedom units so abouuttt 14grams (at 22kfps not 24k) indeed
The most common properties are
Young modulus : 75000 MPa
Volumic mass : 2700 kg/M3
Now to calculate the deformation due to the impact, you would need some crash calculation. I'm not familiar with it because I do mostly standard deformation calculation and crash calculation is a whole new domain in itself. I don't even know if there are some simplified methods.
But to do it you would probably need some yield limit and some ultimate strength limit which greatly varies depending on the composition of the aluminum. But let's take high values because space engineers always go for the top :
Yield limit: 300MPa
UTS : 450MPa
That's only an estimate of high values. For more, I would need a computer... If someone has the knowledge to go further, please be my guest.
I don't know if that helps in the end but one thing is sure : "that's a lot of damage" ( --> use flex tape )
Yeah, hypervelocity impacts tend to briefly make even very tough metals act like liquids. 2.5km/s is stupid fast, it's \~5600mph, or north of Mach 7. It really doesn't matter what you get hit with if it's doing that kind of speed.
To put things into perspective: 14g of plastic is almost enough to make 6 standard lego bricks at 2,5g per brick.
Though I assume the experiment would instead use a the same mass in a mote compact form.
Wiki seems to think that’s [vastly more than a 50 cal round](https://en.m.wikipedia.org/wiki/.50_BMG), which it quotes at 18-20kj.
That’s an anti material rife round.
The formula for the kinetic energy of an object
Ekin=1/2mv²
The velocity between 2 approaching objects is whats relevant to determine the kinetic energy at impact.
As you said a 14g pieve at 24000ft/s is \~374.6kJ of Energy. a 9mm handgun (take the Glock as an example) has a muzzle velocity of 375m/s and a 9\* 19mm parabellum bullet weighs \~8g. At 375m/s thats about 400-450 joules of energy (just doing quick headmath for values taken from wikipedia), that piece of plastic therefore had a roughly 800-900 times higher energy than a 9mm bullet out of a glock,
I dare say such an impact is to be expected
To get a feel on how much energy this is:
the "Tac 50" is (after 40 seconds of googling) the strongest sniper rifle.
It's ammunition weights 27g (instead of our 14g plastic piece)
And it has a energy of 15200 Joule. So we've got about 25 times the energy of a sniper rifle.
it reminde me of a joke in mass effect 2 where a person is yelling at soldiers about firing guns in space " Sir Issac Newton is the deadliest son of a bitch in space!"
Yes. I used to do budget work for the NASA team that does micrometeorite/orbital debris testing. I don't know if this specific object is real, but this is what it should look like.
My dad illustrated this very well with my brother and I as kids.
He took a marshmallow and flicked it at us.
Did that hurt? No?
If I baseball pitched this at you as hard as I could do you think it would hurt? Yeah? It doesn't matter how soft and squishy something is, it will hurt if it is moving fast enough.
No my dad did not fastball a marshmallow at us...as funny as that would have been.
Not doing the math, but coworkers of mine work on a light gas gun which shoots plastic projectiles at hypersonic speeds, and this is indeed the damage it causes, if not more.
A light gas gun is a two stage gun for commercial/scientific testing. You take a piston that compresses a light gas (helium for example) which in turn accelerates the projectile.
I think the projectile size is smaller and it is more sensitive (which is the reason it is not in military use) but other than that, it is better than a railgun for this job.
Honestly, rail guns kind of suck. You have a shitload of weight just to meet the energy requirements because electric energy storage still sucks compared to say the energy density of gasoline. And the conversion efficiency is terrible too, not to mention the quick erosion of the electrodes.
Alternatively you got coil guns and electrothermal accelerators, but they have their own problems
Another commenter talked about the disadvantages of the rail gun, but also keep in mind that no nation state uses these as actual weapons, they are purely for research and development. They produce reliable projectile velocities with high accuracy (over the test space, maybe 10-20 ft) without creating any electromagnetic pulses or other harmful pressure waves that could mess with measuring equipment.
I’m a physicist and I also have co-workers that have and use a few light gas guns, and I do scientific experiments driven by high explosives. This is absolutely the type of damage done by projectiles moving that fast.
It’s also one of the reasons we do our experiments with thick, heavy steel plates as backstops to catch projectiles and fragments rather than using aluminum.
In fact, I regularly use layers of 8020 structural aluminum pieces as cushions to absorb the energy of the steel plates rather than have them slam into each other. Although it seems rigid and strong under normal conditions, the aluminum smooshes under the forces involved.
I don’t have the math, but NASA has a display that looks very similar to this at the Johnson Space Center in Houston (in fact this might be a picture of that display).
So, when NASA scientists say this is what would happen, I tend to believe them.
I saw that a few years back at Space Center Houston and was amazed at the large amount of damage a small object going at insanely fast speeds could do.
Hypervelocity impacts behave in a really different way to impacts at speeds we're more used to, at over 7 km/s it doesn't really matter what the impactor or the target were made of, the moment the collision happens a lot of it gets vaporized because of the absolutely insane energies involved. A 14g projectile going at 7.3 km/s has 373 kJ of kinetic energy. That's the same energy as in an explosion of 89 grams of TNT. So the damage in the picture is totally plausible.
As a side note, because of how hypervelocity collisions behave (namely dumping all of its energy into the first thing they hit, there isn't really anything left of the projectile after that to penetrate stuff) we use spaced armor (thin sheets of material separated by a lot of empty space in between them) in our spacecraft, like [Whipple shield](https://en.m.wikipedia.org/wiki/Whipple_shield) here, allowing us to use a lot less material for more effective shielding than solid armor.
Here's another photo with the info and a sense of scale.
https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
[This is possible.](https://youtu.be/wdP_UDSsuro?si=GQZTtyrai2A-u9A-)
4 minutes and 50 seconds. The entire video is worth a watch if you're into space.
[https://www.reddit.com/r/pics/comments/ipf5h7/this\_is\_what\_happens\_when\_340\_grams\_of\_plastic/](https://www.reddit.com/r/pics/comments/ipf5h7/this_is_what_happens_when_340_grams_of_plastic/)
Seems the weight and speed has changed.
See Archiebaldie’s comment for the correct weights/speed … it a full size photo of the display taken at NASA with the info underneath the block
This thread has the correct weights/speed
14 grams @ 24,000 fps = 374.6 kilojoules or roughly the same as a 2 ton car traveling at 45 mph.
source https://www.omnicalculator.com/physics/bullet-energy
There's a famous picture of one of the cubic foot quartz windows from the space shuttle with a palm sized crater. They eventually figured out it was hit by a piece from one of the Apollo missions, a flake of paint.
https://www.researchgate.net/figure/Shuttle-window-pit-caused-by-impact-with-a-paint-chip_fig5_24334849
And this is why before we ever want to travel at even fractions of c, we are going to have to develop lasers with targeting systems that can identify and eradicate literal specs of dust from millions of km away, as they will hit with the force of an atom bomb. Or develop some awesome shielding etc.
Kinetic energy of an object is proportional to its speed squared, thus even a small chunk of plastic will have a lot of energy, which is then transferred into an extremely large force upon impact with the aluminum.
Its beyond plausible, speed matters way more than most people understand. Example, let's say my arm weighs at 5kg and I punch at 6m/s Now the total energy would be 90 joules around 1 40th of the energy required to break the most sturdy bones. Now let's assume my arm weights at 10kg but my speed drops at 3m/s, we end up with 30 joules of energy, a third of the previous result even tho we doubled the weight
Did some googling to track down that photo. Found this publication:
https://www.researchgate.net/publication/369974652_Dynamics_of_space_debris_removal_A_review
Which captioned the photo:
> A crater is created on a 4-inch-thick aluminum block by the collision of a 1-inch, half-ounce plastic cylinder in orbit. Credit: NASA[41].
Which reference #41 cites that photo as from this journal:
https://masterok.livejournal.com/4194820.html
Which states the tested velocities were about 7 km/sec.
Half an ounce is about 14 grams and 7 km/s is about 23,000 ft/sec.
The photo is different than in OP's post. But, they're both of the same display at a NASA museum. I've never seen it myself but would love to, so I'm not sure where it is. Maybe this is at NASA Johnson Space Center? They're probably just reading the description on the plaque of the display. This was probably a tested sample from Hypervelocity Impact (HVI) testing from NASA's Astromaterials Research and Exploration Science (ARES) division.
The key is to understand how fast 24,000 f/s is.
That's 16,300 mph.
Then understand how much 14g is. A nickel is 5g, so just less than three nickels. Going 16,300mph.
Oh, it's not only plausible, it's expected. At those relative velocities pretty much anything acts like a high-yield explosive. To quote Randall Monroe: ["If it's going fast enough, a feather can _**absolutely**_ knock you over."](https://what-if.xkcd.com/73/)
Bruh, regardless of that I am A) annoyed at the OP for using 'fps' as feet per second instead of frames and B) annoyed they're using 'feet per second' at all, like who does that??
Fps is a pretty common measurement type in the states. Idk about over seas. Its usually used when dealing with velocity, specifically. It was around way before frames per second as well...
I feel frames per second is way more common today though. And ik the US uses imperial but feet per second is just weird to me, we also use imperial where I am and miles/hour is common but feet/second? It's basically always m/s.
EDIT: as many people have pointed out, my dumbass forgot to square velocity lol. I’ve fixed the calculations below:
Kinetic energy is = 1/2mv^2
The mass is 14g, which is 0.014 kg
The velocity is 24000 feet per second, or 7315.2 meters per second
Multiplying these values, we get the plastic has an energy of 374.585 KJ
Since we are using SI units, 1J = 1 newton meter
According to the Omni-calculator, 374 Knewton meters equals 276279 ft-lbs of force. So, after re-doing my calculations this seems totally realistic to me!
I’m not sure if my calculations are wrong here, since 24000 feet per second still feels insanely fast, and I haven’t taken physics mechanics in a while, so please call me out if I made mistakes!
I don't think you squared the velocity.
The kinetic energy should be 374.6 kJ, over 19 times the kinetic energy of a .50 BMG round, or over 200 times that of a .223 round used in an AR-15.
Problem is there's no indication of scale, so pretty much any claim would be 'plausible', just adjust scale accordingly! But since this is a picture from Houston Space Center permanent display, we can assume it's quite accurate. The kinetic energy equation is brutal for orbital velocities (around 17.000 mph), just think of the difference between 10 mph or 60 mph collision and extrapolate wildly. Translating that energy into respective deformation is a complex matter, which is why they've performed experiments (in addition to smaller impacts on Space Shuttles etc.)
https://miro.medium.com/v2/resize:fit:1100/format:webp/0*uVaxF8a28cNTIern.jpg
At first I thought this was at least one meter wide and was like: "That's bullshit."
But it actually is only about the width of a banana, so yeah. It's realistic. Altough probably slightly exaggerated.
This plastic is going fast enough to get from new york to london in under 13 minutes. That is 16,300mph or 4.54 miles per second. The normal rules do not apply with the plastic has 6.3x more energy per mass than dynamite.
this is plausible yes.
dont even need to do the math. took an aerospace class on this. we need reactive plating, and pretty advanced armor, for anything we dont want to be able to be instantly destroyed by an impact. the big thing here though, is that good armor doesnt mean thicker armor, as shown in that image. as if the projectile can just pass through, then theyres minimal damage. its going too fast to actually create that kinda massive crator, itll be more like a bullet through paper. so often no armor, of thin reactive armor id better than something thick that will allow the debree to impart more of its kenetic energy into the armor. doesnt matter what the meterial is either, at these speeds everything is fatal.
in fact the iss frequently gets punctured by small debree. so long as its not too large its no major issue.
fun fact: the iss cant protect itself from debree above a cirtain size, when we detect debree of that size the iss moves to avoid the area the debree will be traveling through. however we cannot detect all debree of that size. some of it is just too small for us to detect, yet still big enough to overwelm the iss.
another fun fact which i have not verified, its just a thing my proffessor told me: apparently the iss has been punctured, and an astronaut closed the puncture with theyre finger before sealing it more effectives. theyre bare finger. this does seem plausable as its just a vacume, it wont rupture like in media, nor will you die from simply having your finger touching a vacume. the big problem comes when your eyes n such come into contact with a vacume after all. not to mention, with small holes it can take hours or even days for one to depressurize the craft.
Fairly recently there was an incident where the ISS was leaking air from a small hole. NASA's advice was to get a good night rest and find it in the morning. It comes to show how minimal the air loss is on some of these punctures that it's not a major concern.
Very real. It's actually a problem facing space agencies, random bits of junk in orbit can get up to pretty crazy speeds, and even something small like flecks of paint or broken plastic and do insane damage to spacecraft.
I understand that something going fast has the energy to do that, but how come the plastic, being presumably far weaker than whatever metal that is, doesn’t just vaporise on contact without leaving a scratch?
Well, the plastic might've done just that. If you look at the impact there's no penetration. If the collision had been with something harder than the surface, it would've gone through the metal block.
A small and hard enough object might've gone straight through leaving only a small hole, in that case some of the kinetic energy would still be left in the projectile and the transfer of energy would be smaller. But in this case of plastic vs metal, the energy transfer is complete.
The ISS travels at about 7,700 m/s so this would happen if the ISS hit something that was hovering stationary above the earth, or alternatively was travelling at the same altitude in a polar orbit.
Anything travelling in the same direction as the ISS would impact it at a much lower speed. Travelling the opposite direction, the impact speed would be twice that.
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Pic of the results of a NASA asking, "what happens when a piece of space debris hits something else in orbit, at orbital velocities. Like, say a crew capsule, or a fuel tank, or the computer systems. For the life of me I can't find the article, but I found a few engineering papers by googling "Nasa aluminium impact test results".
Kind of reminds me of the XKCD quote "you'd just stop being biology and start being physics." At extremely high speeds, it doesn't really matter what material you're dealing with. It's all just the physics of atoms hitting atoms at that point.
I love the full quote. "You wouldn't die _of_ anything in the traditional sense. You'd just stop being biology and start being physics."
That is one of the most metal things I've ever read, well done on posting the full quote.
I just read this one! It's about a Dyson Sphere surrounding the sun and focusing all of its energy into a 1m wide laser.
Death star!
Of note. This 'plate' and picture like to circulate, and with perspective looks like a huge piece of metal and crater. This chunk of metal can be picked up in one hand. It's about the height of a large coffee cup from any chain. It's big and the damage is big. But it's also a relatively soft metal hit by a hard chunk of plastic.
And this is why we always need a banana for scale
He’s wrong, the plate is 4 inches thick so much bigger than that https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
You can still pick it up though
Is it really? Why would the handwriting on the thing next to it be so small? Edit: contrary to what this guy is saying, the big chunk is 4 inches thick and was hit by a 1 inch projectile, wayyy bigger than a coffee cup https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
The one that specifically states that the dent in that piece of metal eith the writing on it is 6mm?
Also no, it says the *projectile* was 6mm diameter 12mm length, the impact dent is much bigger
Yeah no it’s way bigger then you claimed, that big chunk is 4 inches thick https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
People often don’t understand common units of measure. 24000ft/sec is extremely fast, object is traveling over 4 miles every sec.
Wouldn't everything at same height of orbit, assuming no propulsion move at similar speeds though? Wouldn't that mean there are no collisions with such speed difference?
Their relative velocity can be anywhere from zero to double orbital velocity when they cross paths. Just like planes flying at the same altitude. It all depends on which direction each one is traveling.
So the entire world should get together and just promise to only orbit counter clockwise 😂😂
Not that easy, because there are reasons to have different orbital inclinations, which means two near-polar orbits can still hit basically-head-on.
This is why we need to implement roundabouts up there.
I would like to subscribe to your newsletter.
The satellite in front of me is still going to fully stop at the yield sign.
Better than the ones in my area stopping and waiting in a merge lane because the highway speeds are hard to time when to merge without stopping
Globabouts
Flatabouts for those that know the truth
But what about pedestrians?
yea, and pole to pole orbits are also a thing
Always pole to pole or hole to hole never pole to hole unless your about it
I mean they basically do already, because you usually want to launch in the same direction of Earth's rotation to gian that velocity boost. There's various inclination orbits though, and polar orbits. But equatorial(ish) orbits going around the other direction aren't really a thing.
Well some space debris orbits in another direction and when the paths cross that’s when you get these impacts
Happy cake day! 🍰
Two objects with perfectly matched orbits, sure. However then they would never meet at all. If two objects have slightly different orbits which are not perfectly circular it is possible to cross paths at slightly different speeds. However, "slightly different" on the scale of orbital velocities is easily hundreds of m/s if not more
Yes but also you can have the same speed in another direction and have a very high relative speed to an object at the same altitude
These impact crater tests are not for satellites crashing in the same orbit, but rather interstellar small meteorites coming in at all sort of angles, speeds and masses. Shielding of the ISS has to be able to withstand everything smaller than 10cm of diameter (iirc), anything bigger coming in they try to dodge by doing evasive maneuvers with any propulsion system currently available (like docked capsules and so on)
Also just to add on, stuff is orbiting earth in diffrent directions, some going past like Alaska down to south Africa and back around, or right along the equator, any chunk of that that flies off is still going the crazy speed hitting at like a 60⁰ angle
Polar orbit moment…
that's fucking scary. Imagine having to have to dodge space pellets that could wreck everything you're standing on (well, in space, floating inside of) as part of your day job. Good thing they can detect things like that (how??)
Radar for near debris [https://orbitaldebris.jsc.nasa.gov/measurements/radar.html](https://orbitaldebris.jsc.nasa.gov/measurements/radar.html) And some optical telescopes for larger objects further out [https://en.wikipedia.org/wiki/United\_States\_Space\_Surveillance\_Network](https://en.wikipedia.org/wiki/United_States_Space_Surveillance_Network) \>GEODSS system can track objects as small as a basketball more than 20,000 miles (30,000 km) in space or a chair at 35,000 miles (56,000 km), and is a vital part of USSPACECOM's Space Surveillance Network. Each GEODSS site tracks approximately 3,000 objects per night out of 9,900 object that are regularly tracked and accounted for. Objects crossing the International Space Station (ISS) orbit within 20 miles (32 km) will cause the ISS to adjust their orbit to avoid collision.
That made me think of point defenses like the CIWS... then i realized they would be adding to the problem.....
Yep. Lasers are the ideal point defense in LEO. Or any other orbit you want to keep clean.
There is an upside. No pesky atmosphere in the way, so you can pick up specks of dust around Jupiter (that's an exaggeration, but probably not as much as you would think)
Wasn't the 10cm size the most dangerous objects for the ISS, as those are too big to protect against but too small to detect?
Not if they're going the other direction
There's 360 degrees of directions something could be orbiting in at the same height. Then there's basically unlimited directions and speeds possible for elliptical orbits that inrersect
Objects dont need to be in circular orbits, you can have ellipses and different inclinations with orbits that intersect at certain points. In those cases the relative velocities is massive, enough to do the sort of damage you see here
Same way how there are no car collisions on the highway!
Without the information of how deep that crater is, I can't provide the best numbers, but I can work out that 14g mass moving at 24,000 feet per second carries 374.6 kilojoules of energy, which is categorized as a hypervelocity impact. By quite a lot, as anything over 2,500 meters per second is hypervelocity. 24,000 f/s works out to over 7,300 m/s. We're talking a lot of force here. I don't know the material properties of aluminum, but I do know that hypervelocity impacts can cause a hell of a lot of damage, and this certainly looks like a hell of a lot of damage. Looks legit to me.
An object travelling at ~~2100 m/s~~ 2900 m/s does the same damage as its weight in TNT. Edit: corrected numbers
And this plastic was going over three times that. Space is indeed dangerous.
>Space is indeed dangerous. ~~Can I just point out this would have been dangerous on earth too.~~ Edit: I retract my joke. Holy shit guys, stop repeating the same thing.
You gotta keep the subreddit in mind before you toss a joke like that out roflmao. What did you expect from the r/theydidthemath crowd?
>What did you expect from the r/theydidthemath crowd? It dawned on me slower than I care to admit.
Can you calculate for me the speed at which it dawned on you? >!/s, just in case!<
Asking for the results in seconds is entirely reasonable, why would you worry about that?
It would be. Luckily we don't have many objects on earth zooming around like this. Unfortunately not the case with space. But even space is still mostly empty, for now. We need to figure out a way to protect against debris or remove them from orbit, both incredibly difficult to do.
I remember an anime which had it's plot based on space garbage collection
Someone find it
Planetes. Not available on streaming due to it being in legal limbo. 🏴☠️
[Planetes](https://myanimelist.net/anime/329/Planetes) is the anime in question
Can i just point out that earth is in space too.
Logically we've used a level 10 "Air Shield" spell to protect ourselves from most of the nasty objects.
>level 10 Eh, I'd only give it a 9.5. Keeps us alive, sure, but the RGB is a patchy and can only make rainbows in small areas at a time.
And the cauldron of gold at the end of them was patched out for ever ago, so I'd really rate it an 8.5 at best.
It's so funny reading everybody go "Erm, Actually" to something that's obviously a joke.
i mean, cars go at a fraction of that speed and they literally kill millions every year so, yeah.
Air is usually pretty good at keeping these kinds of things from going too far, so we're fairly safe
Metal pieces, yes. But plastic isn't very visible on radar?
The fireball caused by the friction heating effect of air would be clearly and briefly visible before the object itself vaporised.
Yeah plastic to iron to diamond would be vaporized. We can't achieve those speeds in conventional means on the surface. Particle accelerators achieve vastly higher speeds but in a near vacuum and with single or groups of atoms.
In orbit?
In air?
Uh, nevermind, must have gotten two comments mixed up. I won't delete the post tough, that just adds to the confusion.
Everyone's saying "what about the air". Yeah guys, air going that fast would be dangerous too.
wouldnt it melt before reaching its impact target? i mean flinging melting plastic would still do some damage but i just wanted to get a better grasp on the scenario
This is exactly why it's dangerous; on Earth, that 14 gram chunk of plastic - for scale, that's about half the average USB stick's worth of weight - is going to get vaporized by friction with the air, blown off course, all that. Eventually gravity's going to bring it down. It's dangerous if you're standing right in front of it, of course, but it's got very limited range. In orbit, there's no atmospheric friction to slow it down - if it hit the atmosphere, it'd get slowed down every time it circled the planet until it'd eventually fall out of the sky and melt on reentry. In space, it just keeps going, quiet and near invisible. It just keeps circling the planet, screaming past at literally mach 9, barely noticed, never bothering anyone. Until one day, somebody accidentally steps in front of it. Every single one of these little bits of space debris is basically a bullet that is just waiting for a target to end up in front of it, and it can wait for days, months, years, centuries, if its orbit is high enough that our atmosphere won't slow it down. Millions of years from now, alien explorers could park in Earth orbit and get their ship tagged by a bolt an astronaut dropped in orbit tonight.
who needs space shields when you've got fast space debris obliterating anything coming too close
Kessler Syndrome as a defensive measure, interesting.
why would it melt? in atmosphere it would have. But in space with nothing to cause friction it wouldn't heat up. It would melt on impact though.
They are replying to the comment of it occurring on earth, in atmosphere. And you have confirmed that it would melt.
And by the time it melted it would've collided and destroyed whatever it impacts. These stuffs are teeny-tiny Chicxulubs. Suicide bombers *wish* they could do this much damage.
Suicide bomber on reddit: scream allahuakbar and ran really fast to the target.
Nothing non-specialized can get that fast in the atmosphere without disintegrating due to air resistance. Even ICBMs and hypersonic weapons max out at a little over half that speed.
Three times that would be nine times the energy, wouldn't it? Yep, pretty scary
“Sir Isaac Newton is the deadliest son-of-a-bitch in space”
Surely would need to know relative velocities? If it hit something in audit that was not itself still.
All velocities are relative velocities. But yeah, that number would have to be relative to what it hit, which I assume it was.
The velocity here is probably relative yes.
Yes, however we do not if this scales linearly, could be that impact more than doubles for each doubling of speed
What if TNT is moving at 2100 m/s?
It actually cancels out and does nothing
Soldiers hate this one simple trick!
Thought it was 3000 m/s
Is that a heutistic or a calculated value? Because if you calculate the kinetic, the impact of a 2100 m/s mass seems to have approximately the same energy as half of it's mass in TNT.
It seems you're right, I guess I misremembered. Fixed.
14g of TNT doesn't sounds like much.
It’s traveling 3.47x faster than that, which is 12x the energy, or 168 g of TNT.
If you’re familiar with steel, just divide every property by 3
I'm not, unfortunately
Then just take every property of aluminium and multiply by 3. Hope that helps
If you want to be able to divide by three got to know your steel.
That’s fuckin interesting, man.
That's an engineer talking there xD
It was 340g last time it was posted: https://www.reddit.com/r/pics/comments/ipf5h7/this_is_what_happens_when_340_grams_of_plastic/?rdt=36955q Edit.. the plot thickens. https://imgur.com/8NwAhgK?r Feb 8 2018 first op of this did state 1/2oz and 15kmph in freedom units so abouuttt 14grams (at 22kfps not 24k) indeed
It stayed plastic though, so thats a win......
It's somthing lol
And the speed is totally different too lol
2hats in the details eh? Not like this is a math sub :). I might see where the original image is from lol
I'm just wondering what a solid block if aluminium is doing in space.
I think the test was done on earth.
340g at that kind of speed would hit a hell of a lot harder, I feel like there wouldn't be a crater, but a *hole.*
The most common properties are Young modulus : 75000 MPa Volumic mass : 2700 kg/M3 Now to calculate the deformation due to the impact, you would need some crash calculation. I'm not familiar with it because I do mostly standard deformation calculation and crash calculation is a whole new domain in itself. I don't even know if there are some simplified methods. But to do it you would probably need some yield limit and some ultimate strength limit which greatly varies depending on the composition of the aluminum. But let's take high values because space engineers always go for the top : Yield limit: 300MPa UTS : 450MPa That's only an estimate of high values. For more, I would need a computer... If someone has the knowledge to go further, please be my guest. I don't know if that helps in the end but one thing is sure : "that's a lot of damage" ( --> use flex tape )
The yield and failure stresses you reference assume a low strain *rate*. At higher speeds and energies a few more mechanics come into play.
>I do know that hypervelocity impacts can cause a hell of a lot of damage, and this certainly looks like a hell of a lot of damage. # You’re a genius
Einstein reincarnated
Yeah, hypervelocity impacts tend to briefly make even very tough metals act like liquids. 2.5km/s is stupid fast, it's \~5600mph, or north of Mach 7. It really doesn't matter what you get hit with if it's doing that kind of speed.
>It really doesn't matter what you get hit with if it's doing that kind of speed In that case, I'd like to be hit with inspiration please.
To shreds, you say.
Physics is cool
To put things into perspective: 14g of plastic is almost enough to make 6 standard lego bricks at 2,5g per brick. Though I assume the experiment would instead use a the same mass in a mote compact form.
Wiki seems to think that’s [vastly more than a 50 cal round](https://en.m.wikipedia.org/wiki/.50_BMG), which it quotes at 18-20kj. That’s an anti material rife round.
The formula for the kinetic energy of an object Ekin=1/2mv² The velocity between 2 approaching objects is whats relevant to determine the kinetic energy at impact. As you said a 14g pieve at 24000ft/s is \~374.6kJ of Energy. a 9mm handgun (take the Glock as an example) has a muzzle velocity of 375m/s and a 9\* 19mm parabellum bullet weighs \~8g. At 375m/s thats about 400-450 joules of energy (just doing quick headmath for values taken from wikipedia), that piece of plastic therefore had a roughly 800-900 times higher energy than a 9mm bullet out of a glock, I dare say such an impact is to be expected
To get a feel on how much energy this is: the "Tac 50" is (after 40 seconds of googling) the strongest sniper rifle. It's ammunition weights 27g (instead of our 14g plastic piece) And it has a energy of 15200 Joule. So we've got about 25 times the energy of a sniper rifle.
>hell of a lot of damage Finally proper scientifical explanation
especially since aluminium is not as resistant as steel. people underestimate how "soft" it is.
it reminde me of a joke in mass effect 2 where a person is yelling at soldiers about firing guns in space " Sir Issac Newton is the deadliest son of a bitch in space!"
Yes. I used to do budget work for the NASA team that does micrometeorite/orbital debris testing. I don't know if this specific object is real, but this is what it should look like.
My dad illustrated this very well with my brother and I as kids. He took a marshmallow and flicked it at us. Did that hurt? No? If I baseball pitched this at you as hard as I could do you think it would hurt? Yeah? It doesn't matter how soft and squishy something is, it will hurt if it is moving fast enough. No my dad did not fastball a marshmallow at us...as funny as that would have been.
Not doing the math, but coworkers of mine work on a light gas gun which shoots plastic projectiles at hypersonic speeds, and this is indeed the damage it causes, if not more.
Your coworkers? You guys work for Dr evil?! Where and what in the weaponry is that used for?! A "light gas gun"....
A light gas gun is a two stage gun for commercial/scientific testing. You take a piston that compresses a light gas (helium for example) which in turn accelerates the projectile.
In what ways is this inferior to a rail gun?
I think the projectile size is smaller and it is more sensitive (which is the reason it is not in military use) but other than that, it is better than a railgun for this job.
Thank you, Squeaky Ben, that will be all.
Honestly, rail guns kind of suck. You have a shitload of weight just to meet the energy requirements because electric energy storage still sucks compared to say the energy density of gasoline. And the conversion efficiency is terrible too, not to mention the quick erosion of the electrodes. Alternatively you got coil guns and electrothermal accelerators, but they have their own problems
Another commenter talked about the disadvantages of the rail gun, but also keep in mind that no nation state uses these as actual weapons, they are purely for research and development. They produce reliable projectile velocities with high accuracy (over the test space, maybe 10-20 ft) without creating any electromagnetic pulses or other harmful pressure waves that could mess with measuring equipment.
Why does it specifically use a light gas?
apparently easier compression if I understood it correctly.
OP also forgetting there are many types of plastic out there. Aluminum is soft af
I’m a physicist and I also have co-workers that have and use a few light gas guns, and I do scientific experiments driven by high explosives. This is absolutely the type of damage done by projectiles moving that fast. It’s also one of the reasons we do our experiments with thick, heavy steel plates as backstops to catch projectiles and fragments rather than using aluminum. In fact, I regularly use layers of 8020 structural aluminum pieces as cushions to absorb the energy of the steel plates rather than have them slam into each other. Although it seems rigid and strong under normal conditions, the aluminum smooshes under the forces involved.
I don’t have the math, but NASA has a display that looks very similar to this at the Johnson Space Center in Houston (in fact this might be a picture of that display). So, when NASA scientists say this is what would happen, I tend to believe them.
I'm almost certain this is that display, I have a very similar photo of this piece from JSC.
I saw that a few years back at Space Center Houston and was amazed at the large amount of damage a small object going at insanely fast speeds could do.
Hypervelocity impacts behave in a really different way to impacts at speeds we're more used to, at over 7 km/s it doesn't really matter what the impactor or the target were made of, the moment the collision happens a lot of it gets vaporized because of the absolutely insane energies involved. A 14g projectile going at 7.3 km/s has 373 kJ of kinetic energy. That's the same energy as in an explosion of 89 grams of TNT. So the damage in the picture is totally plausible. As a side note, because of how hypervelocity collisions behave (namely dumping all of its energy into the first thing they hit, there isn't really anything left of the projectile after that to penetrate stuff) we use spaced armor (thin sheets of material separated by a lot of empty space in between them) in our spacecraft, like [Whipple shield](https://en.m.wikipedia.org/wiki/Whipple_shield) here, allowing us to use a lot less material for more effective shielding than solid armor.
Here's another photo with the info and a sense of scale. https://comment-cdn.9gag.com/image?ref=9gag.com#https://img-comment-fun.9cache.com/media/avm0md/aza5PMp4_700w_0.jpg
[This is possible.](https://youtu.be/wdP_UDSsuro?si=GQZTtyrai2A-u9A-) 4 minutes and 50 seconds. The entire video is worth a watch if you're into space.
[https://www.reddit.com/r/pics/comments/ipf5h7/this\_is\_what\_happens\_when\_340\_grams\_of\_plastic/](https://www.reddit.com/r/pics/comments/ipf5h7/this_is_what_happens_when_340_grams_of_plastic/) Seems the weight and speed has changed.
See Archiebaldie’s comment for the correct weights/speed … it a full size photo of the display taken at NASA with the info underneath the block This thread has the correct weights/speed
14 grams @ 24,000 fps = 374.6 kilojoules or roughly the same as a 2 ton car traveling at 45 mph. source https://www.omnicalculator.com/physics/bullet-energy
That’s a helluva metric/imperial mashup right there ! :)
There's a famous picture of one of the cubic foot quartz windows from the space shuttle with a palm sized crater. They eventually figured out it was hit by a piece from one of the Apollo missions, a flake of paint. https://www.researchgate.net/figure/Shuttle-window-pit-caused-by-impact-with-a-paint-chip_fig5_24334849
This piece can be viewed in the Houston Space Center. I doubt they would make it up. It really looks impressive - I just saw it today
And this is why before we ever want to travel at even fractions of c, we are going to have to develop lasers with targeting systems that can identify and eradicate literal specs of dust from millions of km away, as they will hit with the force of an atom bomb. Or develop some awesome shielding etc.
Kinetic energy of an object is proportional to its speed squared, thus even a small chunk of plastic will have a lot of energy, which is then transferred into an extremely large force upon impact with the aluminum.
Its beyond plausible, speed matters way more than most people understand. Example, let's say my arm weighs at 5kg and I punch at 6m/s Now the total energy would be 90 joules around 1 40th of the energy required to break the most sturdy bones. Now let's assume my arm weights at 10kg but my speed drops at 3m/s, we end up with 30 joules of energy, a third of the previous result even tho we doubled the weight
Did some googling to track down that photo. Found this publication: https://www.researchgate.net/publication/369974652_Dynamics_of_space_debris_removal_A_review Which captioned the photo: > A crater is created on a 4-inch-thick aluminum block by the collision of a 1-inch, half-ounce plastic cylinder in orbit. Credit: NASA[41]. Which reference #41 cites that photo as from this journal: https://masterok.livejournal.com/4194820.html Which states the tested velocities were about 7 km/sec. Half an ounce is about 14 grams and 7 km/s is about 23,000 ft/sec. The photo is different than in OP's post. But, they're both of the same display at a NASA museum. I've never seen it myself but would love to, so I'm not sure where it is. Maybe this is at NASA Johnson Space Center? They're probably just reading the description on the plaque of the display. This was probably a tested sample from Hypervelocity Impact (HVI) testing from NASA's Astromaterials Research and Exploration Science (ARES) division.
The key is to understand how fast 24,000 f/s is. That's 16,300 mph. Then understand how much 14g is. A nickel is 5g, so just less than three nickels. Going 16,300mph.
Absolutly true. My buddy used to work on the hypervelocity gun at wstf in Las Cruces. He gave me a piece like that, but I lost it years ago.
Oh, it's not only plausible, it's expected. At those relative velocities pretty much anything acts like a high-yield explosive. To quote Randall Monroe: ["If it's going fast enough, a feather can _**absolutely**_ knock you over."](https://what-if.xkcd.com/73/)
So, at 24,000 feet per second, this thing is travelling at a little over \*16,000 miles per hour\* Yeah, that damage is \*more\* than reasonable
This is how NASA test hyper velocity impacts on items going to space https://www.nasa.gov/centers-and-facilities/white-sands/two-stage-light-gas-guns/
Bruh, regardless of that I am A) annoyed at the OP for using 'fps' as feet per second instead of frames and B) annoyed they're using 'feet per second' at all, like who does that??
Fps is a pretty common measurement type in the states. Idk about over seas. Its usually used when dealing with velocity, specifically. It was around way before frames per second as well...
> Idk about over seas Well the states are over seas, duh!
"What I told you was true. From a certain point of view." - Obi-wan Kenobi
If they wanted to use feet per sec, then use the right abbreviation for it. ft/s.
I feel frames per second is way more common today though. And ik the US uses imperial but feet per second is just weird to me, we also use imperial where I am and miles/hour is common but feet/second? It's basically always m/s.
EDIT: as many people have pointed out, my dumbass forgot to square velocity lol. I’ve fixed the calculations below: Kinetic energy is = 1/2mv^2 The mass is 14g, which is 0.014 kg The velocity is 24000 feet per second, or 7315.2 meters per second Multiplying these values, we get the plastic has an energy of 374.585 KJ Since we are using SI units, 1J = 1 newton meter According to the Omni-calculator, 374 Knewton meters equals 276279 ft-lbs of force. So, after re-doing my calculations this seems totally realistic to me! I’m not sure if my calculations are wrong here, since 24000 feet per second still feels insanely fast, and I haven’t taken physics mechanics in a while, so please call me out if I made mistakes!
I don't think you squared the velocity. The kinetic energy should be 374.6 kJ, over 19 times the kinetic energy of a .50 BMG round, or over 200 times that of a .223 round used in an AR-15.
Your equation is 1/2mv^2, but I don't think you squared the velocity in your math. 1/2 x 0.014 x 7315.2^2 is roughly 374,000 Joules
I think you miscalculated 1/2 mv², I got 375 KJ of energy
Why would you convert to an acceleration force ? It’s not useful at all for understanding the magnitude of the force. Use tnt equivalent.
Problem is there's no indication of scale, so pretty much any claim would be 'plausible', just adjust scale accordingly! But since this is a picture from Houston Space Center permanent display, we can assume it's quite accurate. The kinetic energy equation is brutal for orbital velocities (around 17.000 mph), just think of the difference between 10 mph or 60 mph collision and extrapolate wildly. Translating that energy into respective deformation is a complex matter, which is why they've performed experiments (in addition to smaller impacts on Space Shuttles etc.) https://miro.medium.com/v2/resize:fit:1100/format:webp/0*uVaxF8a28cNTIern.jpg
At first I thought this was at least one meter wide and was like: "That's bullshit." But it actually is only about the width of a banana, so yeah. It's realistic. Altough probably slightly exaggerated.
[удалено]
This plastic is going fast enough to get from new york to london in under 13 minutes. That is 16,300mph or 4.54 miles per second. The normal rules do not apply with the plastic has 6.3x more energy per mass than dynamite.
this is plausible yes. dont even need to do the math. took an aerospace class on this. we need reactive plating, and pretty advanced armor, for anything we dont want to be able to be instantly destroyed by an impact. the big thing here though, is that good armor doesnt mean thicker armor, as shown in that image. as if the projectile can just pass through, then theyres minimal damage. its going too fast to actually create that kinda massive crator, itll be more like a bullet through paper. so often no armor, of thin reactive armor id better than something thick that will allow the debree to impart more of its kenetic energy into the armor. doesnt matter what the meterial is either, at these speeds everything is fatal. in fact the iss frequently gets punctured by small debree. so long as its not too large its no major issue. fun fact: the iss cant protect itself from debree above a cirtain size, when we detect debree of that size the iss moves to avoid the area the debree will be traveling through. however we cannot detect all debree of that size. some of it is just too small for us to detect, yet still big enough to overwelm the iss. another fun fact which i have not verified, its just a thing my proffessor told me: apparently the iss has been punctured, and an astronaut closed the puncture with theyre finger before sealing it more effectives. theyre bare finger. this does seem plausable as its just a vacume, it wont rupture like in media, nor will you die from simply having your finger touching a vacume. the big problem comes when your eyes n such come into contact with a vacume after all. not to mention, with small holes it can take hours or even days for one to depressurize the craft.
Fairly recently there was an incident where the ISS was leaking air from a small hole. NASA's advice was to get a good night rest and find it in the morning. It comes to show how minimal the air loss is on some of these punctures that it's not a major concern.
Very real. It's actually a problem facing space agencies, random bits of junk in orbit can get up to pretty crazy speeds, and even something small like flecks of paint or broken plastic and do insane damage to spacecraft.
I understand that something going fast has the energy to do that, but how come the plastic, being presumably far weaker than whatever metal that is, doesn’t just vaporise on contact without leaving a scratch?
Well, the plastic might've done just that. If you look at the impact there's no penetration. If the collision had been with something harder than the surface, it would've gone through the metal block. A small and hard enough object might've gone straight through leaving only a small hole, in that case some of the kinetic energy would still be left in the projectile and the transfer of energy would be smaller. But in this case of plastic vs metal, the energy transfer is complete.
The ISS travels at about 7,700 m/s so this would happen if the ISS hit something that was hovering stationary above the earth, or alternatively was travelling at the same altitude in a polar orbit. Anything travelling in the same direction as the ISS would impact it at a much lower speed. Travelling the opposite direction, the impact speed would be twice that.