I've been seeing a lot of this "Rods from God are going to hit with the force of nukes" Going to post screencaps because business insider is really shit clickbait but this is what I keep seeing. I don't understand how can they generate more force than it took to get them up there? My understanding is that we put work in to move them to space using energy, storing that energy as potential energy, then when we release them the potential energy is translated into kinetic energy equal to the energy required to get them there minus friction and other energy loss.
Educate me, how does Kinetic Bombardment work, is it cost effective/will it ever be, and does the "simple math" actually add up to a weapon with nuclear fusion levels of force?
>I've been seeing a lot of this "Rods from God are going to hit with the force of nukes" Only from people who don't understand physics They would deliver less than a quarter kiloton and it would mainly be focused downwards with little explosive effect
>I don't understand how can they generate more force than it took to get them up there? You are correct they can't They use the energy to launch, boost to a stable orbit, then require more energy to forcibly de-orbit them
> My understanding is that we put work in to move them to space using energy, storing that energy as potential energy, then when we release them the potential energy is translated into kinetic energy equal to the energy required to get them there minus friction and other energy loss. Mainly correct
>Educate me, how does Kinetic Bombardment work, is it cost effective/will it ever be, and does the "simple math" actually add up to a weapon with nuclear fusion levels of force? It could only be feasable if we become able to generate DU or mine tungsten in space
Xavier Lopez
PE=MAH = weight*9.81 (meters/second)(height in meters)
in actuality you're adding a fuck ton of potential energy and converting to kinetic energy when you let go. there is your simple math.
i ain't a physicist, i'm just a chem E student. but as for how it gains acceleration (assuming it means after it has hit terminal velocity), i have no idea.
Benjamin Hill
자격증 기회 놓치지 말래잖아
Dominic King
back of envelope maths
20 ft cylinder, 1ft rad of tungsten would weigh roughly 350tons
It took Saturn V to take a 15ton lander and command module to the moon
Eli Martinez
They don't generate more energy than they cost to bring up there. They lose a bit due to drag losses (but look at them, they're pretty sleek). They'll be cost effective if we have asteroid mining because then we don't need to drag our telephone poles out of the gravity well.
If a telephone pole is 40 feet tall and 1 foot wide then that's about 31.5 cubic feet, which is about .89 cubic meters. Tungsten is 19.3 grams per cubic centimeter which means the pole weighs 17,200 kilograms. In Low Earth Orbit an object must be moving at least 7.6km/s, and is 400km high. At 400km up you're only feeling .9g of acceleration, so I'll say it averages .95g for the entire descent. You've also gotta slow down a little to actually intersect the Earth, so I'll say you drop to 7.5km/s to timely hit your target.
Kinetic energy is 1/2 mass * velocity^2 and potential energy is mass * acceleration * height.
So your energy on impact without air resistance is 17,200/2 * 7,500^2 + 17200 * (9.81 * .95) * 400,000. That gives me 5.47e11 joules. 547 Gigajoules. That's comparable to the energy released by 1 gram of matter and one gram of antimatter annihilating (1.8e11), and 10 times as big as a Davy Crockett tactical nuclear weapon (4.8e10, 0.01 kiloton yield). The MOAB is 5e10 joules and a one kiloton nuclear weapon is 4.18e12 joules.
Multiply that 5.47e11 number by whatever percent speed you think it retains to the ground. If it loses 10% speed, multiply it by 0.9 to get its actual impact.
It's not an atom bomb, but it's a very precise, VERY powerful weapon that doesn't suffer any fallout (nuclear or political).
Parker Collins
Yes it takes the same amount of energy but the laws of physics dictate that force is pressure divided by area. Small area of the space needle gains all of the energy used to push it up to space however incurs none of the penalties of gravity or drag that the rocket had. You therefore have a denser projectile with less drag and better aerodynamics. Basically your mum's dildo taken up a skyscraper and dropped.
Xavier Allen
>in actuality you're adding a fuck ton of potential energy and converting to kinetic energy when you let go. Where did you get that potential energy? You had to gain it in the ascent, it doesn't appear.
Nolan Reyes
What density are you using for tungsten? That's 20* 0.5^2 * pi cubic feet and tungsten is 1201 pounds per cubic foot.
Zachary Richardson
Also the math says they would be very efficient at turning their gravitational energy into damage. A nuke has a lot of energy unloaded into a small area which disperses. For the energy yield it's actually not very good at penetration. A THOR weapon system turns a much smaller amount of energy into a very deep "stab". Into a more efficient bunker buster, without fallout. Also when you take into account the cost of making a space flight capable nuclear weapon kinetic energy weapons are not outrageous in cost.
Samuel Perez
Long rock float in space. Long rock acted upon by fire. Long rock fall to earth. Long rock go faster and faster. Long rock survive entering Earth’s atmosphere. Long rock fall even faster. Long rock hit ground. The speed (Kinetic Energy) built up goes everywhere (the rod releases it’s KE at the moment of impact. This results in a large explosion). Long rock hit city. Long rock destroyed city. Long rock not nuclear, so city is dead but not glowy.
Blake Harris
That’s still a fairly big boom for a rock dropped from space. Think a salvo of these rods could wipe out a major city?
Dominic Parker
>how do they work
drop a ping pong ball on your foot from waist height
now drop a bowling ball on your foot from waist height
now throw that motherfucking bowling ball at your food as hard as you can
Bear in mind that a nuke releases its energy in a sphere whereas this drops it all onto a single one-square-foot patch of target. Also imagine a weapon that drops flechettes as it passes.
A good rule of thumb for high velocity projectiles: at 3 km/s an object carries kinetic energy equal to its weight in TNT. And because kinetic energy goes with the square of velocity, at 6km/s it's four times its weight, and so on.
Grayson Baker
Proposal. Strong as fuck chain. >connect to rod in desert >connect other end to stuff in space. >Winch >space rods ready for hardcore penetrating action.
And the 6m long tungsten rod? It does not have to be a singular monolithic construction. It could be smaller, it could be assembled.
It could be a shorter reentry vehicle for destroying ships or lightly hardened targets. I could see a naval use easily. Rather than nuke a anchorage you mission kill the enemies naval assets.
It also could be a Tungsten tipped open body rod loaded in orbit with any convenient mass to get the KE needed for the specific target. What ever is easier to lift to orbit in pieces or acquire assuming we get space based industry.
And if/when we get to populations living in space they would be easy to make and quite probably the weapon of choice.
Did you ever drop something, OP? That’s pretty much how it works.
Liam Foster
>book about polyandry fetish Hard pass.
Joshua Ortiz
>Rods from God, How do They work They don't Thats CGI Your budget went to Israel and into free stuff for Israel needs to assert dominance on sandnigger levels.
Jonathan Smith
Misplaced decimal I was meaning to work at 19250kg/mm3
Caleb Flores
Where did this meme come from and why does anyone think that hyper expensive lawn darts in space is a viable weapon.
Still a nice idea about mass drivers being re purposed for war. And yea RAH was a kinky sob apparently...
John Allen
No Major cities are fucking massive.
Aaron Baker
>And the 6m long tungsten rod? It does not have to be a singular monolithic construction. It could be smaller, it could be assembled. It would need to be solid or deep entry would fracture
>It could be a shorter reentry vehicle for destroying ships or lightly hardened targets. I could see a naval use easily. Rather than nuke a anchorage you mission kill the enemies naval assets. How are you guiding this? static targets is 1 thing but remote guidance in the plasma sheath of re-entry?
>It also could be a Tungsten tipped open body rod loaded in orbit with any convenient mass to get the KE needed for the specific target. What ever is easier to lift to orbit in pieces Lets make a weapon that works purely on mass and then lets REDUCE that mass - Brilliant And multiple launches to create a single rod? each one is a huge energy loss alone never mind multiple ones
Hudson Richardson
Apparently Russians, US, China and India are...
Adam Ramirez
>In the case of the system mentioned in the 2003 Air Force report above, a 6.1 m × 0.3 m tungsten cylinder impacting at Mach 10 has a kinetic energy equivalent to approximately 11.5 tons of TNT (or 7.2 tons of dynamite). The mass of such a cylinder is itself greater than 9 tons en.wikipedia.org/wiki/Kinetic_bombardment#Real_life_concepts_and_theories
Liam Howard
how to counter this? shoot it to pieces?
Daniel Ward
blow up your enemie's spy sats so they can't target it blow up the satellite that launches them
Brody Ortiz
ram a satellite made of steel into the launching station in orbit.
Carson Roberts
mooseun mal.
Elijah Evans
Have your satellite maneuver over and spray some paint on the targeting sensors.
Rods from god are like IRBMs except you always know exactly where they are, giving away the whole point.
Jordan Young
I think you fucked up your math Also, Saturn V was able to put 100 tons in low earth orbit, where this weapon would be deployed
David Sullivan
the higher it is, the easier it will be to actually use the thing and the less juice you need to use to do it, because you need to cancel its horizontal momentum before it will start to drop GEO or above is the best bet even though it'll take longer to fall
Anthony Jenkins
s500
Matthew Richardson
You're basing the viability of this based on current chemical rocket limitations.
What if this were combined with railgin/coilgun tech here on Earth that could achieve escape velocity relatively efficiently? I'm thinking like a converted mineshaft up in Rockies. The accelleration forces and heat involved that would destroy any other meaningful cargo or person aren't really a factor if you're just lobbing a stick into space.
From there you can capture and store that energy for later use at any time, essentially giving your railgun the ability to strike any static target on the globe. You can also; with enough prep, essentially fire as many escape-velocity-power railguns as you want at the same time at your intended target.
The added benefit is that this prep can be done on a 9-5 basis domestically by civilians to project the same power militarily and globally. Sounds like a decent idea to me.
Evan Lee
What? I don't think I understand what you are saying But, to be clear, it is harder (understand needs more fuel and thus less payload) to have a satellite in GEO than in LEO. Just because the speed is lower at GEO (3km/s) does not mean it is easier than LEO (7.7km/s).
Ethan Clark
getting a hunk of tungsten into orbit isn't the issue here, it's having enough delta V left over so that you can stop your orbit and have it fall that is easier the higher up you are
Eli Rogers
No. A few city blocks at max. You have to realize this isn't an airbursting weapon designed for vast swathes of destruction, it's an explicitly non-nuclear antibunker weapon.
Ethan Rivera
Definitely not a good solution Even though you might touch and even explode on the rod, it'll most likely keep going, only slightly changed in course You would have only deviated a little bit from it's course
Joshua Ramirez
The penetrator doesn't "stop its orbit" and fall straight down, it's placed into a rapidly decaying orbit by its launch platform. Imagine a tight spiral from exoatmospheric orbit down to the point of impact; a gross oversimplification but basically that is the mechanism they use.
Tyler Bailey
so it comes in at a retarded angle and aerobrakes to the target
Carter Price
No, you stupid nigger. Read up on orbital mechanics and get back to me.
Austin Miller
By literally moving the rods high up into the atmosphere. You move a rock up a hill with kinetic energy and now at the top you have potential energy. You let the rock roll back down the hill converts the potential to kinetic and now at the bottom of the hill, it is at a lower potential energy than before... have you not taken physics before?
Wyatt Morgan
I'm literally repeating what you just fucking said you absolute idiot
Justin Moore
>THIS WEEK ON FUTURE WEAPONS >THEY CALL THEM THE RODS OF THE GODS, AND THEY CAN WIPE OUT A WHOLE CITY FROM SPACE
Jose Williams
THE ROD WILL STRIKE THE RING HE ROD WILL STRIKE THE RING E ROD WILL STRIKE THE RING
ROD WILL STRIKE THE RING OD WILL STRIKE THE RING D WILL STRIKE THE RING
WILL STRIKE THE RING ILL STRIKE THE RING LL STRIKE THE RING L STRIKE THE RING
STRIKE THE RING TRIKE THE RING RIKE THE RING IKE THE RING KE THE RING E THE RING
>decaying orbit is the same as aerobraking Die in a fire.
Nathan Adams
No it not Braking to have an intercepting orbit with the perigee at sea level is harder the higher you are. If you're at GEO, you effictively need to lower the perigee 36000km Whereas at leo, you only have to lower the perigee 400km. However, the rod will be way more potent (going roughly 11km/s compared to a mere 7,5 km/s if it were to be dropped from leo)
Michael Walker
Such a weapon will never be developed, let alone fielded due to their limited application and the extreme costs associated therewith. Performance-wise, they’re only unrivaled in the task of bunker busting or for the rare occasion that you might need the equivalent force of a small yield nuke but without the radiation which is too rare and unforeseeable a circumstance to justify the cost and resource expenditure in setting up and maintaining such a system to begin with. As a replacement for conventional artillery, rocketry, or aerial bombardment? Pfffft I know, it’s a cool “what if” speculation thing, but it’s never going to happen because there’s other systems that out perform the concept at a lower cost, are more versatile, and have a lower time on target. We live in the nowpunk piss earth where xhamster and the nofap website argue on twitter amid the background chatter of corporate accounts pretending to shitpost and be “woke” as a marketing strategy, ancom junkies and art students take to the streets to commit violence in the name of what is basically HR policy and have branded themselves the resistance despite enjoying a vast extra-political institutional support network, and stronk empowered female drone pilots rain death on weddings and then double tap the site when emergency services shows up. Embrace how fucking gay it is. >“When seconds count, the rod is only minutes away” -scrawled on some colonial marine’s helmet 200yrs from now
it's literally the same thing, because if your orbit is decaying you're losing energy somewhere and that energy is being lost into the goddamn atmosphere because you're aerobraking the whole thing is that you'll have enough energy left to lithobreak afterwards lowering your perigee is easier the slower you are you're slower the higher you are think about it, you have less speed to cancel the higher you are
Joseph Foster
There is a MUCH higher chance of this being used as an advanced bunker buster than a WMD. You’d take out a few blocks at most and would if anything be a waste of a rod. That London scene in the one GI Joe movie is mostly bs.
Kevin Butler
kek
Kevin Peterson
You cannot instantaneously stop an orbit. You don't understand how gravity works. Stop posting.
Dylan Robinson
>Educate me, how does Kinetic Bombardment work, is it cost effective/will it ever be, and does the "simple math" actually add up to a weapon with nuclear fusion levels of force?
1. vaguely, but not that well. 2. fuck no, massively expensive. 3. fuck no, the air force laughed it out the room.
Isaac Walker
of course not, it'll take a few minutes for a rocket to do it, but you could have a railgun launch itself away from the rod to give it enough delta V rather quickly I just realized the pro-strat is to have a constellation of these guys in highly eccentric orbits so they're moving even slower when they're way out in space
Josiah Cook
>You cannot instantaneously stop an orbit. Go back to Quora and stay there
Jordan Clark
Well yes and no It all depends on the loss of altitude in the perigee GEO You are around 3km/s and altitude 36000km above sea level (42500 km from center of earth). If you want to lower the perigee of 500 km (and have an elliptical orbit of 42000-42500) it'll cost you an amount of delta V that I'll call X1. Now you want to lower the perigee all the way to ground level, 6500 km, effectively having an orbit of 6500-42500. This maneuver will need 1 delta-v of X2 (around 1500m/s BTW) Leo You are around 7.7km/s and altitude 500 km above sea level (7000km from center of the earth). If you want to lower the perigee of 500 km (and have and intercepting orbit) it'll cost you an amount of delta-v I'll call Y. Now, with all that, you are trying to compare X1 and Y. And by saying that X1 is smaller than Y, you are absolutely correct. 100% However, X1 will never get you to earth, you'll need X2. And X2 is an order of magnitude higher than Y, I'll tell you that.
Finally: remember that most GEO sats need a large engine to get a circular orbit once at apogee but a soyuz or a space shuttle only need a small burn to deorbit.
screw GEO and have a highly eccentric orbit out to GEO distances from LEO, do the math on that please
Luis Carter
That's not the problem, the problem is time. It would take days to build up the energy. Think an orbit around the moon then sling shot it back to earth 3-4 days lead time notice on that target. Expense when has that ever stopped a plan. Yes it works but its faster to just hit what ever you want to hit with a rocket. Maybe it works as a retaliation for doomsday but that would be the extent of its use.
Colton King
Yes, this works pretty well. Having a highly excentric orbit like most communication satellite before being in circular orbit would yield great results. Those orbit (geostationary transfer orbit, gto) are around 42500-7000, give or take. And to lower the perigee a little more so that it intercept the earth would be easy (understand low fuel consumption) Three caveat though 1- those orbit are not very precise as they tend to move and oscillate with time. 2- given the orbit, you'll need multiple launcher to be sure to have always one at apogee over all possible targets 3- a gto orbit is still more energetic than a leo orbit meaning lower launch weight.
Jordan Kelly
don't burn up to GTO until it's time to target then
Owen Reed
>Expense when has that ever stopped a plan. quite often. maybe go read a dod budget one day. >Yes it works but its faster to just hit what ever you want to hit with a rocket. works? the energy yield is literally fuck all for the money involved, go read the air force report. >Maybe it works as a retaliation for doomsday but that would be the extent of its use. sure, i am going to retaliate with a peashooter. sure i am.
James Wright
more thoughts: burning up to GTO then a targeting burn is more attractive than dropping from (probably polar) LEO, even if it means a lower payload weight due to the higher speeds achieved and not needing to literally traverse a bajillion miles through the atmosphere laterally which seems like a terrible plan
Julian Young
Running a very simple matlab script with your numbers comes up with ~1.971 km/s at impact, or ~3.339E10 J of energy.
Jacob Reyes
>downward with little explosive effect. Wrong. On small scale yes, but when scaled up the energy and velocity is far too much, the energy spreads out radially like an explosion. I'll give you the small yield though.
Angel Cooper
here For the record, I used the inbuilt standard atmosphere and a Cd of 0.01 to calculate the terminal velocity profile.
Levi Jenkins
>seeding an area with atomized heavy metal Long term effects are almost as bad as radiation.
Hunter James
yeah but the media isn't scared shitless of heavy metal poisoning unless you mention lead by name or actively point out that it's heavy metal poisoning
Ryder Brooks
Thor was a viable system - just an exceedingly, stupendously expensive one. It's basically orbital bombardment with gigantic lawn darts; you could do just as well (albeit with some comparative loss of accuracy) by simply deorbiting space rocks at the right spot.
Also, any already-in-space civilization is going to find Thor a much more doable prospect, if they can mine asteroids and create darts that way rather than lift them from the surface to begin with.
>RAH was a kinky sob apparently... Try Time Enough For Love.
Ian Martin
Thanks! That's quite a lot of energy lost. Still hauling ass, but not as much as you'd hope. Is the script you used available online? I'd like to have it.
Caleb Richardson
>stronk empowered female drone pilots rain death on weddings and then double tap the site when emergency services shows up Are you sure you're not mixing up fantasy with reality? That's a straight up scene from [spoiler]Gundam 00. [spoiler]Bitchy pilot gets upset at someone having a wedding while she's stuck blowing up various militaries so she blams the entire wedding as she passes it in her mech on the way to her next mission[/spoiler][/spoiler]
Isaiah Richardson
shoot your own rod at the enemy orbital rod cannon
Plus your deorbit strike isn't to achieve a lower circular orbit, you're intersecting the earth's surface.
Jack Walker
I think Rome is just as likely as Moscow
Evan Hall
No one cares about Rome though. Italy is irrelevant and Vatican is even more so.
Mason Adams
yeah but it's a fucking prophecy it doesn't give a shit about what you think
Isaac Sanders
Oi fuck off? When Russians get crushed by a giant rock i'll make a thread telling you i was right
Julian Roberts
yeah you're misinterpreting that line would be funny tho
Wyatt Harris
You best believe that son
Jose Jenkins
I think that actually happened in real life in Pakistan though. Some CIA guys drone striked an Islamic wedding and when the medics and the tribal troops showed up they drone striked them again.
Henry Taylor
The energy in such cases only spreads marginally in radial terms, the spread is due to transference ones the vector of energy release is saturated. It would have little explosive effect as this guy said - or do you think for some reason that Sabot has the same "Explosive" effect as DPHE
Aaron Thomas
>I don't understand how can they generate more force than it took to get them up there? Maybe you don't get them up there. Maybe you build them on the moon or something. But that's hardly their only problem.
And remember, the whole reason behind the concept was a nearly undetectable first strike capability against Soviet nukes that wouldn't give them time to launch. I don't think launching a first strike was ever a scenario that either superpower seriously planned.
Benjamin Carter
>Where did this meme come from The 80s. Just like caseless.
Evan Jenkins
DU would be bad, but tungsten isn't toxic.
Jaxson Smith
>Try Time Enough For Love. Try I Will Fear No Evil. Brain transplant into female body. Or... What's the one where Jubal has himself cloned with his Y chromosome replaced with another copy of his own X? IIRC he has two clone "daughters" and ends up fucking them. Is that incest or masturbation?
James Diaz
There was also a cockpit/FLIR vid where an Apache pilot waited several minutes for clearance to fire, and when he got it, did not wait a few more seconds for an oblivious civilian strolling down the sidewalk.
Thomas Johnson
If that number is accurate, it is probably referring to the total expense of designing the whole system, building it and getting it into space.
