Rods from God, reconsidered

[DDE]

8 hours ago, Nuke said:

i don't know if machine vision systems would be reliable enough for ordinance delivery,

Scud-D used autonomous TV guidance for CEP of 50 m.

11 hours ago, kerbiloid said:

If hit a nuclear country, they can react with mass launch.

This seems to rely on perception of a strict dichotomy between nuclear-biological-chemical and everything else.

That might work the atomophobic public, or with China's no-first-strike pledge, but not with Russia and both its doctrine and the concept of "strategic conventional" weapons.

11 hours ago, kerbiloid said:

If hit a non-nuclear one, why these efforts.

There seems to be at least a faction in the US MIC that really, really wants to loosen the criteria for use of nuclear weapons or surrogates thereof, stymied only by public perceptions and very dubious excuses ("if you nuked Tora Bora, the Taliban would be able to scrape together the unburnt nuclear fuel").

Hence high interest in low-yield nukes (e.g. the most recent Trident upgrade), in pure fusion nukes (since these supposedly would present none of the radioactive PR mess associated with a nuclear strike), potentially of even smaller yields and with 'augmented effects' like CASABA-HOWITZER, and hence the discussions of a pure-kinetic Trident around 2006.

To this faction, the promise of a non-nuclear but nuclear-equivalent weapon is incredibly attractive.

[kerbiloid]

1 hour ago, DDE said:

That might work the atomophobic public, or with China's no-first-strike pledge, but not with Russia and both its doctrine and the concept of "strategic conventional" weapons.

I mean, to covertly deorbit the rods to hit all silos at once to disarm the opponent without significant collateral damage,
following the known rule of two warheads from different missiles per target,
one should launch at least twice as many rods as there are silos, ABM launchers, big radars, and other primary targets,
i.e. about a thousand of rods.

As the rod can be launched only near the apogee, they should have at least two sets of the rods.
Of course, they can launch them in perigee at let them make one half of turn more, but this:

• makes to perform burns close to the on-ground telescopes;
• adds 12h of flight time;
• even if doesn't hurt the accuracy, still doesn't makes easier the synchronization of rods arrival.

So, they need ~2000...3000 rods in orbit for that (and each of them requires a Titan-IV/Proton-class rocket to deliver).

Next, they can have all 1000 rods on a single platform. So, about 200 such satellites is required.
And as they can't orbit aside, and the rods can't arrive all at once, the "sudden strike" turns into a 12..24 hours long lazy bombardment.
So, the rods can suddenly take out just several percent of silos, while others will launch rockets just before get hit.

***

So, looks like the rods can suddenly disarm only a country with 10-20 silos (a nuclear newbie or after deep nuclear disarmament), but the same can be done with usual missiles.

1 hour ago, DDE said:

Hence high interest in low-yield nukes (e.g. the most recent Trident upgrade), in pure fusion nukes (since these supposedly would present none of the radioactive PR mess associated with a nuclear strike), potentially of even smaller yields

After they at least declared that US doesn't have tactical nukes except B-61 anymore.
So, it's a tactical Trident. About 10 warheads, iirc, so probably 2 missiles.

***

Imho, all this pure kinetics story will result into a subkiloton self-guided nuclear penetrator.

Edited October 5, 2019 by kerbiloid

[wumpus]

On 10/4/2019 at 2:27 PM, Dragon01 said:

Do note that the biggest problem with Project Thor is that it just isn't that effective. Such a "tungsten telephone pole" would have an energy roughly equal to its own mass in TNT, and it would go straight through the target, probably depositing most of this energy in the ground below. This is not a WMD. In practice, air drag tends to rob you of any advantage gravity gauge gives you, and deorbiting an object of this size, not to mention orbiting it in first place, are both rather expensive. Such a weapon would have some advantages, but it's a precision "bunker buster" that's also nearly impossible to intercept. To be a precision weapon, it'd need precision guidance, and entry at that speed would make it difficult to implement, especially if we consider the plasma sheath will prevent any forward-looking sensors from being of any use.

I remember hearing that the USAF was dropping bombs with the entire warhead replaced with concrete: the idea was that the guided bombs were so accurate, they didn't need the explosion (which would just hurt people who weren't the target) when dropping a heavy bomb from 10km+.  This would be ideal for such situations.

On 10/4/2019 at 1:49 PM, DDE said:

The two burning questions I see are:

• What kind of a realistic deorbit "burn" (e.g. via railgun) is necessary for maximum retention of kinetic energy on impact?
• What are the effects of the considerable lateral velocity?

I doubt you need a railgun.  I think a Scott Manley video claimed over 100kph could de-orbit something in more or less one orbit.  Actually, it might have been a bit higher than that, as you couldn't throw something that fast (a pro baseball pitcher throwing that slowly will quickly lose his job) but you could presumably de-orbit a golf ball with a golf club (Alan Shepard, eat your heart out), or maybe a Jai alai glove.  I'd expect better accuracy with more delta-v (combined with the inevitable RCS thruster for final guidance).

The lateral velocity would pretty much be part of the "kill area" and make it much more of a line than a "spot".  It would certainly make any damage mitigation tricky, and probably make such a weapon even more useless.

[farmerben]

The Chelyabinsk bolide gave 20 people UV burns similar to sunburn.

Water travelling at sufficient speed through our atmosphere becomes far hotter than a welding flame

[Guest]

8 minutes ago, wumpus said:

I remember hearing that the USAF was dropping bombs with the entire warhead replaced with concrete: the idea was that the guided bombs were so accurate, they didn't need the explosion (which would just hurt people who weren't the target) when dropping a heavy bomb from 10km+.  This would be ideal for such situations.

This is actually not an uncommon idea. Concrete, steel darts (known as "Lazy Dog" in 'nam) and kinetic missiles with pop-up blades (yes! The US had them on their Hellfires for a while) had all been used where collateral damage was a concern. Lazy Dog in particular is great, in that it's cheap, effective and has none of the problems cluster bombs do. Kinetic penetrators dropped from altitude have merit, and considering they had an ABM (the Sprint) that accelerated to 3400m/s (mach 10) in a few seconds, deploying something like that, armed with a kinetic penetrator, would have an effect not unlike project Thor. For large rods, the booster would have to be pretty hefty, but less than trying to launch the thing to orbit. You can't get much faster than that in lower atmosphere, anyway.

[KG3]

Could one of these rods be used to sample the interior of a comet or asteroid?  I know that the Deep Impact spacecraft used a 372 kilogram cooper impactor to make a 150 meter wide crater on comet Temple 1.  Could an 11 ton tungsten rod travel straight through a comet for reasons of science? 

[kerbiloid]

2 hours ago, KG3 said:

Could one of these rods be used to sample the interior of a comet or asteroid?  I know that the Deep Impact spacecraft used a 372 kilogram cooper impactor to make a 150 meter wide crater on comet Temple 1.  Could an 11 ton tungsten rod travel straight through a comet for reasons of science? 

(That's what I'm proposing on this forum for years, but every time read that "this will mix the ground layers" and so on.
Funny, but when they did almost the same on Ryugu(?), the ground layers weren't mixed.)

***

Something similar to the rods, but much more intellectual.
Also with formulas and pictures to estimate the rods penetration.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750004806.pdf

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810012471.pdf

https://digital.lib.washington.edu/researchworks/bitstream/handle/1773/35520/Robinson_washington_0250O_15623.pdf?sequence=1

[Laie]

On 10/5/2019 at 12:02 AM, sh1pman said:

What kind of accuracy would these rods have? 

The most optimistic claims I can see for ICBM is ~100m, and this requires a carefully surveyed launch site. Sub-launched missiles are supposedly in the 1km range, GPS notwithstanding.

Control is probably less of an issue than knowing the precise starting position and orientation in spacetime.

Question is, how close do you need to get?

19 hours ago, wumpus said:

The lateral velocity would pretty much be part of the "kill area" and make it much more of a line than a "spot".  It would certainly make any damage mitigation tricky, and probably make such a weapon even more useless.

This. A hypersonic lump rushing overhead is probably going to shatter windows, and on the last mile even houses. Not sure if you're going to get flash and bang on impact, or merely an earth-shaker. I guess a lot depends on how soft or brittle the ground is.

I cannot even guess how close you need to bring it down to a missile silo in order to take it out of action. Moving enough dirt might already be effective for a few days, even if the silo is otherwise unharmed.

[kerbiloid]

17 minutes ago, Laie said:

Sub-launched missiles are supposedly in the 1km range

With astro-correction (a star scanner) same as ICBM.

[Arugela]

On 10/4/2019 at 1:49 PM, DDE said:

We all know the hyped-up weapons system:

The problem is that the average depiction of such a weapon works as follows:

1. Space station magically floats in space, where there is no gravity
2. An oversized kinetic impactor is released
3. Gravity suddenly feels guilty for being a slacker, and selectively affects the impactor
4. Impactor comes down at close-to-vertical trajectory

Meanwhile, we in the Intellectual Gaming Community know that's not how space works.

Except Project Thor was also envisioned by people who know how space works, so clearly we're missing something.

The two burning questions I see are:

• What kind of a realistic deorbit "burn" (e.g. via railgun) is necessary for maximum retention of kinetic energy on impact?
• What are the effects of the considerable lateral velocity?

Have you consider the simple application of a spring. Stored energy released on demand. Can be stored from any part of the satellites deployment. You could even have a counter spring!!(This allows two things fired at once or more. each with spring in the opposite direction and potentially symmetrical. shh!)

You could also store tons of ammo and reload at will!

GODDAMNED RUSKIES!!!!!

Actually, I would think deploying enough ammo ahead of time could make it useful. If it's not turned against you. I would say maybe using a wired control solution would help. But we know how that could overcomplicate things. Besides the giant funny string headed to space nobody can figure the purpose of. And it potentially wrapping the earth into a giant ball of yarn one day in the future. We would then truly be cat paradise!

To solve the ammo problem you could also just make it in space out of all the space debri. Who needs tungsten? Literally the throw everything and the kitchen sink approach. Even meteors could be used.

 

I actually had a simlary idea about a simlar ICBM like design. You send it to orbit with the warhead on the front and then leave enough fuel to propell it. It would have lots of explosives too. The point would be to dig into hard surfaces like mountains and blow them up with lots of little explosives to remove obstacles.... I called it the sweden bomb. For when the SOBs try to steal our chocolates again!! You got a complaint and you want us to deal with it. We have your solution!!!

The advantage is you can launch it from home.

I also wonder how small you could make them to remove material per warhead to spread out the impact areas... Could you use lighter denser materials than tungsten. Or specialized tips for different materials. Could you use a very small tip to focus the depth of the warhead?

Edited October 7, 2019 by Arugela

[StrandedonEarth]

The reason for tungsten is that it has good density so it that air resistance doesn't slow it down as much. But more important, it has a very high melting point, to survive the descent.

Rods from God may be overkill; telephone pole size impactors may have a nuclear effect but would be expensive to put up there, and WMDs are always a thorny topic. I've always liked the idea of flying crowbars, as anti-material weapons (Footfall describes an orbital strike of flying crowbars against a column of tanks). Again, the main headache is terminal guidance through the plasma sheath.

[DDE]

8 hours ago, StrandedonEarth said:

Again, the main headache is terminal guidance through the plasma sheath.

That, and the delay between firing order and impact can be horrendous, comparable to an airstrike but with much leas flexibility - what's the cross-range of a crowbar?