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Rods from God / "Project Thor"

Orionblamblam

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LowObservable said:
I have heard it theorized, by someone I would regard as an expert, that a shotgun blast on the right scale is exactly what you need against a warship.

It might depend on *when* the blast goes off. If it goes off above the ship, so that there is sufficient time for the hundred or so chunks of hundred-pound slabs of tungsten moving at five kilometers per second to separate enough to get some good coverage of the ship...yeah, it'll make a mess. If it goes off *inside* the ship, it probably won't make a whole lot of difference *to* the ship, though the "exit wound" on the belly of the ship will be bigger. However, even if that action doesn't do much to the ship, by kerploding the rod before it actually hits the water, the kinetic energy of the rod will be deposited into the water a *lot* faster. So you will poke a meaningful hole through the ship and then promptly create an energetic bubble of steam right under the keel.

Not a good day to be in a boat.
 

Dilandu

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Orionblamblam said:
Keep in mind: in order to drop that six ton rod of tungsten on the other guy, you had to expend a de-orbit stage of unknown mass, as well as a whole lot of tons of rocket propellant to boost the system into orbit in the first place. The Falcon 9 Full thrust can put 22.8 tons into orbit (equivalent to 3.75 rods, not counting de-orbit systems...call it three rods), burning through 410.9 tons of propellant in the first stage and 107.5 tons of propellant in the second => 518.4 tons of propellant expended to deliver the equivalent of 3X44.1 tons (132.3 tons) of TNT onto the enemy.

Hmmmmm. Let's assume, that the cost of the whole system would be about 100 millions dollars (50 millions for F9B5 launch and 50 millions for the system itself ). So we have the system, that could within 90 minutes deliver along its orbital path a 130 tons of destructive power.

How much it would cost to deliver the same amount of explosives by conventional means? The cost of modern "Tomahawk" missile, if I'm not mistaken, is about 2 millions dollars (1,82 actually). So the system cost as much as 50 "Tomahawks"... which could deliver to the target about 50 * 0,45 = 22,5 tons of explosives.

* Of course, 50 "Tomahawks" could be used against much more targets, but I must point out, that against well-defended target only a part of those 50 "Tomahawks" would come through. And I must also point out, that 50 "Tomahawks" would not deliver themselves all the way from USA to the target. They needed a carrier vessel - an "Arleigh Burke"-class destroyer, perhaps, or nuclear submarine, which also would cost money. If we use ALCM's instead, we would need enough bombers to carry them.

* Of course, the actual system on orbit would probably cost more than 50 millions, but up until it cost less than the number of "Tomahawks" required to deliver the same amount of explosive power + their carriers, it would be at least partially cost effective.

In short, my IMHO - the "Thor" system is not hopeless. Granted, it is not the system you would call in to destroy the tank column. But it would work great against high-valuable, protected targets, like command bunkers, strategical transport nodes, hardened airfields, ect. For example, something like good ol' "Thor" may be quite a good solution against those Chinese island fortresses in Southern Chinese Sea. To took them out by conventional means, would require quite a lot of efforts. To nuke them, would means a clear escalation to at least tactical nuclear level (and who would benefit more?). But to orbit-strike them with the power of tactical nukes would be both cost-effective, and fairly conventional way.
 

sferrin

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LowObservable said:
I have heard it theorized, by someone I would regard as an expert, that a shotgun blast on the right scale is exactly what you need against a warship.

It would not sink it but it would trash almost every sensor/comms aperture on board.

Back in the day (early 80s) there was a piece of HARM artwork that showed it attacking an old Kresta II class. Presumably, this is exactly the strategy employed.
 

Dilandu

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sferrin said:
Back in the day (early 80s) there was a piece of HARM artwork that showed it attacking an old Kresta II class. Presumably, this is exactly the strategy employed.

I must point out, that HARM would home on radar systems, i.e. would hit the warship around radar antennas. Which means that shrapnel hit is preferable to direct hit, since the probability of hitting tops of masts and superstructures are significantly less than in case of hull attack.
 

marauder2048

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sferrin said:
LowObservable said:
I have heard it theorized, by someone I would regard as an expert, that a shotgun blast on the right scale is exactly what you need against a warship.

It would not sink it but it would trash almost every sensor/comms aperture on board.

Back in the day (early 80s) there was a piece of HARM artwork that showed it attacking an old Kresta II class. Presumably, this is exactly the strategy employed.

Although given HARM's CEP against a moving emitter, I'm not sure they could have employed any other strategy.
 

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Reported by whom? I've never seen a credible claim that orbital bombardment tech was real-world tested or even seriously experimented with.
So I never found what I was looking for in DTIC, but there was this from Jane's International Defence Review, Jan 2006, which just popped up from the depths again on this forum, oddly enough:

"One conventional strike option against hardened targets was demonstrated under a "black" or classified programme in 1978-88. Colliquially known as "rods from God" (a term attributed to science fiction writer Jerry Pournelle), it involved placing small space vehicles containing 15-20 long, dense, inert tungsten rods - 6m long and 0.3m in diameter - in elliptical orbits around the Earth. (There is no treaty restricting the use or deployment of conventional or non-explosive orbital weapons.) The vehicles would achieve ultra-high apogees of almost 65,000km and would eject and de-orbit the rods on demand. When something falls in a vacuum from 65,000km it is apt to be moving rather quickly when it hits the ground, and the concept involved impact speeds of 6,000m/s. It was estimated that the sheer kinetic energy impact would be enough to destroy missile silos. According to analyst Barry Watts of the Center for Strategic and Bugetary Assessments: "A total of perhaps USD70-80 million was spent... including test shots against the Kwajalein Atoll from Vandenberg AFB in California. In the end, however, the programme met staunch opposition from Air Force fighter generals who were not interested in seeing SAC develop a non-nuclear global-strike capability. As a result, the programme was terminated."...
 

sferrin

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An 18,000lb rod of tungsten wouldn't need to fall from orbit to kill a silo.
 

SpudmanWP

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The primary purpose of having it in orbit is response time.

Using a single bomber to drop a single rod is not efficient.
 

Orionblamblam

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The primary purpose of having it in orbit is response time.


Response time from orbit could be many hours. Not just the 90 minutes to go around the Earth, but however many orbits it needs to go through to get somewhere over the target. The cross-range on a rod is likely not spectacular, especially if you want to maintain maximum velocity. Optimally you'd want to shed as little velocity as possible, which means that you would want to drop the rod onto a target that is almost exactly in line with the orbital path. And you may want to impart *just* enough delta V to drop perigee down to ground level, which means the rod would come screaming in nearly horizontally.

All this means that if you have a limited number of weapons in orbit, your targets could be days away. So waht you'd want is to have a *lot* of weapons in orbit. Sure, there will inevitably be foreign government complaining and some members of your own public protesting, but you could simply declare that the protestors are "colluding" with the foreign powers...
 

sferrin

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The primary purpose of having it in orbit is response time.

Using a single bomber to drop a single rod is not efficient.

But imagine trying to get a useful number of them up there and moving them around. A silo would be just as dead with a 100 pounds of tungsten hitting the lid at 6 km/sec.
 

SpudmanWP

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If 100lbs is sufficient then make the RfGs 100lbs (+ ablative shielding) , no need for 9000.

If they are only 100lbs, then there can be many more in orbit so the response time is shorter.

I wonder what a RfG could do to a sub a couple of hundred feet below the surface?
 

Orionblamblam

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I wonder what a RfG could do to a sub a couple of hundred feet below the surface?

Realistically? Probably make a loud "bang" well overhead that spooks the crew. Going faster doesn't seem to greatly increase penetration depth... a couple hundred feet of water would probably stop a RfG quite effectively.
 

edwest

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I get the orbit-deorbit part, what I'm still vague on is total impact force.
 

SpudmanWP

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I wonder what a RfG could do to a sub a couple of hundred feet below the surface?

Realistically? Probably make a loud "bang" well overhead that spooks the crew. Going faster doesn't seem to greatly increase penetration depth... a couple hundred feet of water would probably stop a RfG quite effectively.
If there can be supersonic, rocket powered torpedoes.. why not shape the tip of the RfG to do the same thing or is there some gas generation involved?

nm, Googled it and 'answered my own question'. :)
 

sferrin

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I wonder what a RfG could do to a sub a couple of hundred feet below the surface?

Realistically? Probably make a loud "bang" well overhead that spooks the crew. Going faster doesn't seem to greatly increase penetration depth... a couple hundred feet of water would probably stop a RfG quite effectively.
If there can be supersonic, rocket powered torpedoes.. why not shape the tip of the RfG to do the same thing or is there some gas generation involved?

nm, Googled it and 'answered my own question'. :)


Some use gas-generation to supercavitate. Others use shape.



616105
 

Orionblamblam

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I wonder what a RfG could do to a sub a couple of hundred feet below the surface?

Realistically? Probably make a loud "bang" well overhead that spooks the crew. Going faster doesn't seem to greatly increase penetration depth... a couple hundred feet of water would probably stop a RfG quite effectively.
If there can be supersonic, rocket powered torpedoes.. why not shape the tip of the RfG to do the same thing or is there some gas generation involved?

nm, Googled it and 'answered my own question'. :)


Some use gas-generation to supercavitate. Others use shape.



View attachment 616105
Wait. Is that chart actually saying that bullets will travel hundeds of feet in water? Mythbusters would like a word.
 

sferrin

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Wait. Is that chart actually saying that bullets will travel hundeds of feet in water? Mythbusters would like a word.

Mythbusters wasn't using supercavitating bullets. (I saw that episode too. :) )
 

SpudmanWP

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So... Zeus striking at Poseidon can be a thing.

Rods from Gods.. apply named :)
 

DrRansom

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I have a question: what sort of damage would a 1000kg+ rod dropping at 6 km/sec actually do? I haven't been able to find a study on the Rod from God impact damage.
 

DrRansom

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That article is for asteroids impacting at >11km/s and is a collection of scaling assumptions. The impact of a streamlined solid metal rod at hypervelocities should be very different than an asteroid.
 

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Why don't they use Depleted Uranium? Not only is it denser than Tungsten but it's pyrophoric? Sounds like these rods would make a useful warhead for hypersonic weapons..
 

SpudmanWP

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Cost along with "OMG the US is using nuclear weapons in SPACE!!!!!!!!!!"
 

edwest

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That article is for asteroids impacting at >11km/s and is a collection of scaling assumptions. The impact of a streamlined solid metal rod at hypervelocities should be very different than an asteroid.


I guess we'll never know. How would it work at a Scottish pole toss event?
 

edwest

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And everybody knows who Jormungandr is...
 

Forest Green

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I have a question: what sort of damage would a 1000kg+ rod dropping at 6 km/sec actually do? I haven't been able to find a study on the Rod from God impact damage.
0.5 * m * v^2.

500 * 6000^2 = 18GJ = 4,500kg of TNT (roughly), or roughly the same as a WWII Grand Slam Bomb.
 

edwest

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I have a question: what sort of damage would a 1000kg+ rod dropping at 6 km/sec actually do? I haven't been able to find a study on the Rod from God impact damage.
0.5 * m * v^2.

500 * 6000^2 = 18GJ = 4,500kg of TNT (roughly), or roughly the same as a WWII Grand Slam Bomb.


Thanks. Not as bad as I thought.
 

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And there’s this wonderful “thing” we have where a person can instantly look up information even on their phone.

Alas, even the best search engines are not what they used to be.
 

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Brickmuppet said:
The goal for Falcon Heavy is reportedly 100 launches. One can assume a Chinese equivalent will be similar so 100 launchers give 10 thousand launches which result in 20,000 or 50,000 warshots on station depending on the orbit chosen. In a polar orbit the whole enchilada could be fired at one target in a 24 hour period. Optimistically assuming a firing window of one half hour for each satellite, about 213 shots would be in position over any point on Earth at any time. Optimistically assuming a launch a week per rocket, the USSF or the People's Liberation Army Taikonaut Attack Corps (?) could put this sword of Damocles up in two years or so.


While I'm sure we can all agree that a launch a week for two years of a F9H class booster carrying USSF payloads would be a laudable goal, it would pretty much necessarily cause an arms race... which might or might not be a good thing. As with any satellite, there are chances of something going screwy and the thing falling out of orbit. Usually a satellite coming down results in harmless things like burnt bits of tank landing in the outback or Soviet fissionables scattered across a grateful Canadian tundra, but having tungsten telephone poles belly flopping out of the wild blue yonder could make for some entertaining CNN Personally I think it'd be worth the risk *if* those rods have white stars painted on the side... but if it's a red star, that's not so good.

Launching a *few* of these into orbit makes for an interesting tactical weapon. If the US and China tangle over, say, a Chinese invasion of the Spratleys or Japan, and one side or the other sinks a ship or two with a rod or two... things *may* stay conventional. but if one side has thousands of rounds overhead, they cease to be tactical weapons and become strategic. China sinks an American carrier with one of these from there vast orbital stockpile, chances are fair that the US Navy will respond not with some F-18's dropping JDAMs, but with an Ohio launching a barrage of Tridential howdies.

The Soviets feared that the Space Shuttle could be used to nuke Moscow. I wonder about the possibility of the Starship being converted into a similar role as a carrier for the rods. Musk has promised aviation-like availability rates and if flying in a LEO could probably hit the target within 45 minutes of launch. The Starship could carry around 10 of them.

No need to station them in orbit and start an arms race or militarize space. Leaving them in orbit also makes them more vulnerable and would cost 10s of trillion vs launching from the ground.

What do you guys think? I included the links on the Space Shuttle below.


Bombing missions
Okhotsimsky and Sikharulidze stated in their report that the shuttle would offer several advantages over intercontinental ballistic missiles, as well as so-called “global missiles,” the term the Russians used for rockets that would place nuclear weapons into orbit, after which they would de-orbit themselves and approach US territory from the south. The Soviet Union actually performed flight tests of such a system using the R-36 missile of the Yangel design bureau in the late 1960s and early 1970s (in the West this was known as a Fractional Orbit Bombardment System, or FOBS, and the Russian development of such a system may have led Okhotsimsky and Sikharulidze to assume that the Americans sought a similar capability.) While an ICBM needs just 30 or 40 minutes to reach its target, it spends much of its time at high altitudes (up to 800–1000 kilometers), making it easy to detect. In contrast, because it flies over the South Pole, the shuttle would need 70–80 minutes to reach its target, but flying at an altitude of 185–200 kilometers and approaching the Soviet Union from the south, it would be much harder to detect by Soviet early warning systems. An orbiting nuclear weapon is also easy to detect and its trajectory can be quite easily predicted, making it easy to take countermeasures. It also has a much lower strike accuracy, so they thought the shuttle would be better for this mission.

Okhotsimsky and Sikharulidze then provided an alarming scenario for the American shuttle: a mission with the aim of dropping a “special payload” (in other words, a bomb) on Moscow.

Okhotsimsky and Sikharulidze stated that the shuttle’s crew would make it possible to increase flexibility and even to call off the operation at the last moment. Strike accuracy would be increased by the ability to accurately determine the position of the orbiter before the de-orbit burn. With the help of the US Air Force’s Global Positioning System (GPS) then in development, that accuracy was expected to improve to 50 meters by 1981, and to 10 meters by 1984.

Okhotsimsky and Sikharulidze then provided an alarming scenario for the American shuttle: a mission with the aim of dropping a “special payload” (in other words, a bomb) on Moscow. The shuttle would enter the atmosphere at an altitude of 110 kilometers some 17 minutes after the de-orbit burn at 30 degree northern latitude. Four minutes after entry interface, at an altitude of 67 kilometers and with the orbiter at 47 degrees north, it would drop the bomb, which would hit its target about three to four minutes later at a speed varying between 200 and 500 meters per second. Detection would be made even more difficult by the fact that the orbiter and the bomb would be enveloped by a cloud of ionized gas at altitudes between 45 and 75 kilometers which cannot be penetrated by radio signals. Meanwhile, the orbiter would “turn in such a way that its lift would be aimed upwards with a roll angle of about –30°.” This would enable it to “come out of its dive and perform a lateral manoeuvre” to place it on a trajectory back to Vandenberg. Not having enough speed to reach the launch site, it would fire its Orbital Maneuvering System (OMS) engines (ideally at an altitude of about 100 kilometers) to provide a delta-V of about 200 meters per second. Exiting the atmosphere at a speed of 7.2 kilometers per second at 61 degrees north, the orbiter would reach a maximum altitude of 120 kilometers and then begin its final descent to Vandenberg. In contrast to the initial dive, which would take just 7.5 minutes, this gradual descent would take about 35 minutes.

ground tracks

Illustration from the IPM study showing the shuttle’s dive into the atmosphere and subsequent re-boost maneuver. The light line represents the trajectory of the shuttle and the dark line that of the “special payload”.

One major problem with the scenario portrayed by Okhotsimsky and Sikharulidze was that the shuttle did not have a bomb bay on the bottom of the spacecraft. Instead, it had a payload bay with large doors mounted on its top that could not be opened during reentry. They did not address this issue in their report.

Okhotsimsky and Sikharulidze expected the shuttle to be used to strike “major administrative and military-industrial complexes,” the sudden destruction of which would offer the “attacking side” a major advantage. The shuttle could also be used to destroy mobile targets or “new targets of high military importance detected at the last moment.”


 

edwest

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And meanwhile the X-37B passes in the background unnoticed.
 

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And meanwhile the X-37B passes in the background unnoticed.

Hm? If I recall correctly, she is currently on the ground, preparing to the OTV-6 mission in this year.

Might be just a tad bit too small for a rod. Maybe for a hypothetical Soviet nuclear decapitation strike or the existing reconnaissance mission, the X-37B is perfect.
 

Dilandu

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Might be just a tad bit too small for a rod. Maybe for a hypothetical Soviet nuclear decapitation strike or the existing reconnaissance mission, the X-37B is perfect.

Frankly, I fail to see why do you need a complex, costly recoverable platform just for delivering orbit-to-surface munition. You could build much more cost-effective non-recoverable unmanned strike sattelite for the fraction of cost.
 

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Might be just a tad bit too small for a rod. Maybe for a hypothetical Soviet nuclear decapitation strike or the existing reconnaissance mission, the X-37B is perfect.

Frankly, I fail to see why do you need a complex, costly recoverable platform just for delivering orbit-to-surface munition. You could build much more cost-effective non-recoverable unmanned strike sattelite for the fraction of cost.

You're talking about putting 10s of trillions of dollars worth of munitions in orbit that anyone can see coming. How will they get to orbit? I hope you see the contradiction of needing the BFR to put it in orbit and then claiming that it is too complex to use as the strike platform.
 
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Dilandu

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You're talking about putting 10s of trillions of dollars worth of munitions in orbit that anyone can see coming. How will they get to orbit? I hope you see the contradiction of needing the BFR to put it in orbit and then claiming that it is too complex to use as the strike platform.

What I means, is that it is more practical to use BFR as launch vehicle, not as some sort of reusable orbital bomber.
 

trose213

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You're talking about putting 10s of trillions of dollars worth of munitions in orbit that anyone can see coming. How will they get to orbit? I hope you see the contradiction of needing the BFR to put it in orbit and then claiming that it is too complex to use as the strike platform.

What I means, is that it is more practical to use BFR as launch vehicle, not as some sort of reusable orbital bomber.

They would need minimal modifications to use a launch platform because nothing is ever even leaving LEO. The only question is whether you can get the availability rate needed.
 
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