Talk:Kinetic bombardment

Article

I believe the article Rods from God should be merged into the larger and more general article Kinetic bombardment. Francisco Valverde 21:35, 16 January 2006 (UTC)

Done. Also added science-fiction sections. Scoo 09:37, 28 January 2006 (UTC)

Rods From God seems to be identical to the flying telephone poles version of Thor. Jaxal1 15:10, 16 February 2006 (UTC)

The amount of energy released by these kinds of weapons can be calculated by the formula F= 0.5 m * v^2

F is force, not energy. The whole wiki page needs a re-write to get the physics terms at least partly correct. —Preceding unsigned comment added by 204.188.97.194 (talk) 19:36, 4 December 2010 (UTC)

HIMEOBS? The only reference I can find to this in wikipedia (other than being "an organisation") is under Trolling organisations... 82.1.178.118 15:04, 26 August 2006 (UTC)

Just as a comment in passing, but it was mentioned that a citation is needed for kinetic energy weapons tests being carried out in the Pacific.

US ballistic missile tests traditionally target the Kwajelein atoll in the Marshall Islands (for confirmation, see photographs of MX Peacekeeper test on http://wiki.riteme.site/wiki/Intercontinental_ballistic_missile). Since such tests do not use live nuclear weapons, they are, by default, instrumented tests of kinetic weapons; it's therefore a little redundant asking for citations about a secret KE weapon test, since we know information is gathered about them reasonably regularly at Kwajelein as part of teh ballistic missile testing programme. —Preceding unsigned comment added by 81.158.33.132 (talk) 19:31, 18 September 2007 (UTC)

This is insufficient. An orbital kinetic bombardment weapon of the type described in the article is not going to behave like a ballistic missile test. While it may be possible to model orbital bombing using a dummy ICBM, there is no evidence to this effect, and I am certainly not going to assume it on your say-so. Redundant or otherwise, citation is required for Wikipedia, and you cannot use Wikipedia to cite itself.--Woerkilt (talk) 09:42, 12 July 2009 (UTC)

The rods wouldnt come from GOD, theyd come from the United States Air Force. WHUMP !!! —Preceding unsigned comment added by 65.219.235.164 (talk) 17:30, 13 November 2007 (UTC)

This article would benefit from a description of the effects of a Kinetic strike. Is there such a scientific paper out there? 202.12.233.23 (talk) 12:04, 3 July 2008 (UTC)

Pop culture references: If the use of asteroids in The Shiva Option fits under this concept then the Centauri use of asteroids to bombard the Narn homeworld in Babylon 5 also fits. —Preceding unsigned comment added by 64.31.89.32 (talk) 19:27, 29 April 2009 (UTC)

This wouldn't even work

People tend to forget that the firing stations would be in orbit meaning that they're moving with considerable tangential orbital velocity. This means that rockets will have to be fired to even de-orbit these things. So if you're going to have to fire rockets anyways, why not just put a rocket launcher in space. That's what it's going to take to de-orbit something.... 142.103.207.10 (talk) 18:14, 11 July 2008 (UTC)

A Thor system doesn't deorbit the projectiles. In effect, it just changes the orbit of a projectile to result in ground impact. This change requires a rocket burn to bring the projectile into the atmosphere, after which aerodynamic forces can be used to make further course changes and provide terminal guidance. By preserving the original orbital velocity, the projectile's impact energy can be quite high as described in the opening section of this article. 67.170.198.151 (talk) 18:42, 9 October 2008 (UTC)

So like I said, you'll need to burn some rockets, so wouldn't it be much easier to just put a rocket launcher in space? It would accomplish the same thing, likely be more energy efficient, and give you more versatility in that you can deliver something other than metal rods (eg. you could pack the warhead with explosives). I just don't see the point in calling this some kind of new "kinetic bombardment" technology when it's just a glorified space-based rocket launcher. 142.103.207.10 (talk) 23:45, 4 December 2008 (UTC)

In an aspect you are correct, the idea is a subtle difference in using gravity to provide the ultimate momentum for the impact. A rocket projectile can only achieve a set maximum velocity as a function of the onboard propellant. To achieve simmilar results you would need a massive quantity of propellant. With a Kinetic bombardment system, the rocket used to establish trajectory is a very short burn, probably just a few seconds, then gravity provides the rest. The result is a very energy efficient system that can trade fuel storage space for expanded payload (denser mass). The rocket just gives it a nudge to start moving instead of providing thrust to the final target. Heck you could use a spring to do it as well (with the side effect of propelling your satellite in the opposite direction) attitude adjustment rockets are just alot easier. Halcyonforever (talk) 16:20, 4 February 2009 (UTC)

Halcyonforever, what you said is true for conventional, earth-based rocket. Once you start firing rockets from space at planetary targets, anyone controlling such a weapons system will no doubt have to take gravity into consideration. My point is simply this: imagine we put a rocket launcher in space. Instead of a conventional warhead, we replace its payload with a huge mass of solid metal. Have we now not made a kinetic bombardment system? Is what I've just described not essentially the same as a kinetic bombardment system? If so, instead of inventing a fancy new name for it, isn't it more appropriate to call it an orbiting, space-based rocket launcher that happens to aim down at the planetary surface below it? My main concern about the article is that some readers may interpret this kinetic bombardment idea as being the same as dropping huge blocks like on Earth, but only from hundreds of kilometres up. Of course, we know that due to the "weightlessness" of orbit, just "dropping" an object isn't going to make it go anywhere. A rocket burn would be required and this is not clear from the article. 142.103.207.10 (talk) 22:20, 19 March 2009 (UTC)

Neat Idea, Cold Reality

This article need some substantial technical clarification, because it is full of fantasy and outright errors.

Problems With Orbit

Space-based weapon systems suffer from the same problem as any object in orbit. They can't swoop about like a TIE bomber in Star Wars. Orbital mechanics and environment impose restrictions that are utterly ignored by this article, including:

• Satellites can't hide. Every rocket launch can be tracked, and every payload of sufficient size can be followed. A Rods of God system, which could be the size of a school bus, can be tracked in a good scope-dope's sleep.

• Satellites fly predictable paths. Because they have limited onboard fuel, and because of high traffic, satellites limit maneuvers to station-keeping and dodging space junk. A rival could purchase basic flight maps of enemy satellites, then use dead reckoning techniques to anticipate when and where that Kinetic Bombardment platform is overhead.

• Due to limited maneuverability, Rods from God platforms will also need to ride higher orbits: to avoid ground based anti-satellite missiles, to avoid orbital denial conditions (such as the growing volume of space junk in lower orbits), and to hide from less sophisticated trackers. This increases the flight time of the projectiles.

And that leads me to...

Problems With De-Orbit

Orbital based projectiles are subject to the same laws of physics as meteorites, space capsules and shuttles. One can't just "drop" them or "nudge them" straight down.

• A successful, direct insertion will require burns, requiring a larger and more complicated launch assembly producing a visible infrared signatures (IR). This is hypothetically easier to detect than an ICBM, because ballistic missiles mainly ignite in the ascent, where they can be partially cloaked by various atmospheric effects on the horizon. Missiles may also be able to spoof as civilian rockets. Finally, ICBMs typically coast by the time they reach apogee, whereas a Rod from God is firing away at apogee for the whole hemisphere to see.

• Note that this maneuver is simply to overcome angular momentum and set course. The projectile may lose velocity to atmospheric drag. This means the projectile will need to accommodate aerodynamic controls to correct drift and speed.

• Hull ionization will also generate an IR streak in space. A big hail of steel and tungsten, as described, would also likely appear on magnetic anomaly detectors. Don't forget that an ionization bloom can be picked on radar, too. Under certain conditions and altitudes, this ionization may actually scatter radio waves and thus reduce radar contact--but I think it is more likely to be quite visible.

• Finally Rods from God will take much longer to reach the surface than it's starry eyed proponents propose. Remember, they have to be released from an orbit considerably higher than an ICBM--because you gotta protect your launch platform from anti-sat missiles, space junk, casual observation, and orbital decay. It could take roughly 10 to 45 minutes to descend to the surface, depending on the insertion method.

Overall, the article is quite wrong in asserting that Rods from God will be less detectable than that of an ICBM. It will actually be greater, due to the combination of a exposed altitude, sustained burn, and sustained descent signature. Then of course, there's the separate problem of the lower atmosphere...

Problems With Terminal Descent

You know, the stuff we breathe? The stuff that burns up meteorites, space shuttles, and hypersonic test drones? To maintain the velocity discussed by many novelists and theorists--to hit at specific bunker at Mach 25--is to introduce all sorts of aerodynamic complexities:

• The least of which may be even more rocket burns to counteract drag and shear. In general, a projectile will need some sort of flight control system or it will go off course--especially if the target is moving. Perhaps it can be integrated, but this still means increased bulk, cost, and complexity of the system.

• All of which has to be shielded from the friction generated by the atmosphere at the proposed speeds! Remember, we are talking about a hypersonic kill vehicle here, and it is notoriously difficult and expensive to get anything to travel faster than about Mach 3 in the Troposphere without dispersing into a less destructive and accurate cloud of debris. The density of the stratosphere, too, might possibly shatter a space-born projectile travelling at orbital velocity.

• Fortunately, a projectile does not need to be traveling at orbital velocity to make a big impact. A dense or massive projectile could transfer enough energy at about 3 kilometers per second to effect a kinetic strike. All this crap about orbital velocity is just that. Needless complication of an already complex weapon.

Problems With Fire Control

Finally, such a projectile is not going to be self-guided as Jerry Pournelle and other authors like to imagine. Such a sensor:

A) has to be covered by the aforementioned heat/friction shield, B) or it will be ablated by the friction of re-entry in the lower atmospher, unless it is made out of some exotic material. C) or will obscured by the ionization of re-entry for the duration of the descent.

The idea of dropping a bunch of "crowbars" from 300 to 600 km and trying to shower an armored column strikes me as wishful thinking, especially if that column is moving and spaced like all modern formations should be. It made for an exciting scene in Pournelle's Footfall, but hardly likely. Even if it does work, it would be a hell of a lot more expensive than to deploy a few attack planes or long-range guided missiles. If America ever loses the air edge to the point that we need Orbital Strikes to stop a tank battalion, we are in El Deep Shito.

Such a projectile will require range safety devices. Because the cross-range of an orbital projectile might be severe compared to an ordinary bomb, it will need measures comparable to that of an ICBM or at least a cruise missile. If the Chinese are pissed about one embassy accidentally bombed in Yugoslavia, imagine an entire neighborhood wiped out by a stack of telephone poles. More expense. More complexity. More mass.

Problems of Cost

Everything thus far means money, time, and resources. Tungsten is not that cheap or readily available, even if it is relatively stable in re-entry. A single bundle of telephone poles could consume enough tungsten to armor a dozen tanks, or to form hundreds of cannon shells. And they will not necessarily be cheaper per unit, nor more cost-effective in combat. You have to de-orbit, shield, propel, and correct a dumb projectile as much as a smart one.

Conclusion

I don't know for sure that all of these problems are severe, or even likely, and that's part of the problem too--people aren't considering the challenges. You don't have to be an engineer or a weaponeer to see unanswered questions and basic physical challenges.

Ver 1.0--Woerkilt (talk) 05:14, 6 May 2009 (UTC) Ver 2.0--Woerkilt (talk) 05:36, 6 May 2009 (UTC) Edited and revised for clarity--Woerkilt (talk) 23:52, 13 May 2009 (UTC) Ver 3.0--Woerkilt (talk) 09:19, 12 July 2009 (UTC) Corrected for numerous spelling errors----Woerkilt (talk) 09:29, 12 July 2009 (UTC) Ver 4.0----Woerkilt (talk) 06:38, 30 April 2010 (UTC) Corrected for wordiness and hyperbole.

De-orbit doesn't take a rocket burn, or a rocket-powered pole. It could be launched by a low-v mass driver (coil gun), and the recoil could be negated by an ion drive. Not eliminated, but it could put the satellite back into its correct orbit during a day or two.

The projectile could be mostly of solid metal (say, a very elongated cone rather than a rod) without any moving control surfaces. Steering is done via gyroscope and pointing the nose where it's supposed to go.

Regarding terminal descent, the hard part is that without control systems, the projectile will descend almost horizontally, thus it has to travel through dense atmosphere for several seconds. (Woerkilt hinted at it with the sentence that "one can't just drop them (...) straight down.")

With control, it's likely to steer down somewhat to shorten the final stage of descent and therefore minimize friction, ablation, and loss of kinetic energy.

Regarding problems with fire control: descent could be handled by inertial navigation, that's the only way without relying on any kind of sensors, cameras, or radio receivers (which would be a necessity for GPS).

If you want to hit moving vehicles, predict their path and aim at where they're going to go, ideally on a bridge or in an otherwise confined path so that only their speed, not their direction, must be estimated correctly. The 'rod' could be designed to fragment into 100's of 'needles' showering an area of which the size can be adjusted by timing the fragmentation-to-impact window. Earlier fragmentation = larger area, more room for error. Later fragmentation = more punch per square foot.

It would be more expensive than a wing of GA planes, but faster if you don't have any near the target. What if you have all your forces in Afghanistan, and intel reveals a terrorist convoy moving thru (just as an example) Libya? Dropping a rod is much faster than moving a carrier there.

The final objection was that a satellite launch is much more expensive than an explosive warhead. This could be overcome if a fixed mass driver were used for sat launch; a large percentage of the launch energy would then be converted into impact energy.

Conclusion: There are some major difficulties to overcome, but we didn't go from biplanes to the F22 in one step either. Kinetic bombardment could be a reality by 2050 IMO. User.Zero.Zero.Zero.One (talk) 12:31, 2 November 2010 (UTC)

After writing my objection, I learned more about low delta-v intersection method. It does has its own downside. The projectile may have a minimum time to target of 45 minutes from LEO, coupled with its distinctive flight path. If your launch platform has to be higher to evade surface-to-orbit countermeasures, then this projectile is looking at 1 or more hours of predictable flight. In either case, the projectile is taking longer to reach targets than a surface-launched ICBM, and possibly longer than a cruise missile if there are ships already on station. This is not time to evacuate a city, but officials or control specialists could escape a targeted location. Also, I expect surface elements, especially ships that are already underway, to easily escape the area. A division that is camped out or caught by geography is probably screwed, though.

Otherwise, I can certainly see special purpose use for this weapon. However, I suspect that long-range planes with long loitering times may still beat out the Rods from Gods for practicality, especially since technology advances that permit THOR can also permit "battle-blimps" or advanced UAVs. A orbiter will get overhead faster than a carrier or even an individual plane, I don't doubt that, but it is still limited in its own manueverability and launch window, while its projectile will still have a limited cross-range compared to a B-1 bomber type UAV. What interests me is the role that the US Navy railgun system could play, coupled with the Air Force hypervelocity cruise missile projects. I also suspect that lasers--especially those operating around the green wavelengths--will be cost competative with a THOR. Taking the above example of a terrorist convoy, the laser could hit the targets with virtually no reaction time possible, so long as they lacked the ability to predict the overflight beforehand.

In any event, I still feel this article is weak.Woerkilt (talk) 19:32, 29 November 2010 (UTC)

Earlier versions mentioned some solutions, but I cut them out because I thought I was prattling on too much (that's why you see so many edits). I though about interial guidance and digital dead-reckoning, since they are technologies well-established. I also considered a tail-mounted GPS transciever, but I'm not certain that the signals could cut through the "comet tail" during descent. Perhaps a GPS early guidance followed by onboard gyrocompass for the remainder of flight.

A bigger problem to me is that airshape. Cones and rods seem to be among the worst possible re-entry shapes because of how little surface area they can present. A cone shape, for example, is going to be especially vulnerable near the tip, even if it is tungsten and covered with a carbon cap. Space Shuttles have a thin carbon coating on the leading edges of the wings, but they do not put the leading edge into the path of re-entry, they fall bottom-first so that air-friction is dispersed across the widest possible surface area. Likewise, ICBMs survive re-entry partly because they use a blunt nose, and partly because they descend at considerably less than orbital velocity. With THOR, the entire cone or telephone pole may very well survive entry until impact, but my concern is that even a half-meter of ablation from any areodynamic control surface will be sufficient to alter course, even when it is mere seconds from impact. Perhaps not a richochet off the lower atmosphere, but a drift or a premature explosion nevertheless.

...So how about a THOR system that uses a blunt nose, perhaps combined with an ablative heat jacket, which slows to about 3 kilometers per second before it enters the lower atmosphere? Say, by taking 000's cone and *inverting* it like a Mercury space capsule? One might even get a GPS signal through parts of the descent.And 3 km/s seems to be one minimum effective velocity for an all-kinetic impact.75.170.58.200 (talk) 02:23, 30 November 2010 (UTC)

I'm not sure about that... esp. the fact that Apollo can be seen as an inverted cone during reentry doesn't prove anything. Apollo and (to a lesser extent) the shuttle don't even try to preserve their kinetic energy during reentry. In fact, they try to bleed off as much as possible, for a "soft" landing. Kinetic bombardment has the opposite goal: to preserve energy and hit as hard as possible.

OTOH, this doesn't disprove anything either. - ¡Ouch! (^{hurt me} / _{more pain}) 12:14, 15 April 2011 (UTC)

Exactly, those craft bleed off energy. Too much energy means possible ablation of control surfaces, possible premature detonation due to compression, possible tumbling, reduced-course correction time, inflated radius of corrections to drift and shear, and so on and so forth. These are some of the constraints of "possible" in "hitting as hard as..." In the cone-first format, you've still got that nose that can be chipped away, and the rim of the base as well. Enough small changes in the airshape might build up to uncorrectable course errors, if not uncontrollable descent. I'm not an aerospace engineer, so I don't know for sure. On the other hand, I think the space capsules would make a decent crater if they came down at the right angle without parachutes!

I'm also concerned that an elongated cone might try to invert itself anyways during the descent. With a lighter nose and a heavier base, I'm wondering if aerodynamics would flip the sucker around like a lever. Could the apex of the cone act like an airfoil?

Also, what about a projectile that is deliberately designed to ablate outer layers? As the projectile loses mass, the denser core is still traveling at tremendous velocities. Sort of an incremental sabot system. The area effect of impact might not be very wide, but it could penetrate deeply. Combine this with a flight trajectory that avoids going straight down, and indeed moves as laterally as possible until terminal descent. This way, you could minimize drag, kind of like what 000 is suggesting. But the ablation would need to be controlled so that it too doesn't do something to unexpectedly change the areodynamic characteristics.

Overall, even if a THOR type system could be developed in the next 50 years, its not something likely to ever be used except under similar circumstances as nukes. 000 mentioned mass drivers for hefting the platform into orbit in the first place, more directly translating launch energy into impact energy. Such a satellite delivery system poses its own special problems, and I personally doubt it will be any cheaper than a conventional rocket in this century. In any event, it would be expensive overkill against that hypothetical Lybian convoy. The closest practical thing seems to be ballistic railguns firing sub-orbital projectiles, followed by hypervelocity cruise missiles, and strategic placement of UAVs. 75.170.49.134 (talk) 07:19, 29 April 2011 (UTC)

(Unindenting) Yes, ablation of control surfaces would be crippling, I agree with you 75.170. BTW, I forgot to announce in my last edit that I am the former User.Zero.Zero.Zero.One you called "000". Sorry.

I've seen some iron meteorites which struck the atmosphere tangentially, thus didn't hit the ground very hard. Many of these are shaped like cones. They didn't have that shape initially but assumed it during descent, bleeding away most of their kinetic energy. Thus the cone is known as a shape of 'ablational equilibrium', and if it doesn't bleed as much kinetic energy, it will surely be subject to even less ablation.

I was imagining a kind of 45-degrees cone approx. 1ft diameter, i.e. 6" in length (which is about the shape which said meteorites have), as the nose, followed by a much more elongated section - ~20ft long and widening to a diameter of say 2ft, and finally a fin-tail section 2ft in length, widening to a 3 to 4 ft base. The bulk o fdrag would occur at the relatively blunt tail, holding the projectile in a head-first orientation similar to the fins of an APFSDS. The nose would experience another good portion of drag, and surely the highest pressure, but it would be much heavier than the tail, thus stay in front.

The inmost layer (a ~15ft long, 1ft diameter rod) would consist of DU or similar dense material. It could have a somewhat thinner tail, to improve stability even further and sacrifice very little punch on impact. Around that, one would have less dense materials, e.g. alunimun, lightweight ceramics, carbon-based polymers (wildly guessing), in an onion-like package. As soon as the outmost 'onion' layer is pierced at one point during reentry, it gets torn away by the drag, revealing the next deeper layer which is still smooth. Because the layer gets torn off the slug eventually, it doesn't have much time to transfer heat into the deeper layers or the core. Which could be important, as many heavy metals have very low specific heat values.

Gyroscopes could control the orientation, for example to compensate for air pressure variations, to point the nose down during terminal descent, and to intercept moving targets. It wouldn't have any way to see the moving targets and "home in", but the course wouldn't be 100% set by the de-orbit maneuver either. The updated target coords could be transmitted to the cone until radio contact is broken by the ionised air, which happens only during the later stages of descent.

Back to the gyroes: they would turn the entire cone into a control surface, or at least one of its sides. For example the upper side during terminal descent. Therefore, it would be quite robust and not easily ablated into uselessness.

"its not something likely to ever be used except under similar circumstances as nukes" It's not a WMD, so it could see some usage. And it would come without a radiation signature either (if you use a tungsten carbide flechette and not DU), so it could be mistaken for a natural meteorite.

"Such a satellite delivery system poses its own special problems, and I personally doubt it will be any cheaper than a conventional rocket in this century. In any event, it would be expensive overkill against that hypothetical Lybian convoy." Yes, of course, the launch platform would be utter overkill to one such convoy, but the same can be said about the Land Warrior project vs. one terrorist. The economy will only (if ever) come with scale.

• facepalm* Libya...

And I would use a modified pack against the convoy: a somewhat (2:1? guessing again) scaled-down version, and not a solid rod, but a package of DU/TC 'crossbow bolts.'

"The closest practical thing seems to be ballistic railguns firing sub-orbital projectiles" I think you are mistaking a linear motor for a railgun. I could imagine a mass driver ~50 miles in length deliver standardized satellites into orbit, that is you can put them there during peacetime. A railgun launching THOR rods doesn't look realistic in my opinion.

OTOH, if you continued on Woerkilt's Navy railgun comment, no, that means you still have to have a warship 'nearby'. That's not a significant improvement over a cruise missile, which can already be launched by most warships, although it is a good step ahead the ground attack plane. And lasers are even worse, as they have very low efficiency and need a line of sight to strike. The latter requirement is even more crippling than on most other today's airborne weapons.

Too bad we don't get any good info on the actual projects. All of them appear to be top-secret. And as long as I don't get good sources, I'm not gonna add any of the ideas I mentioned to the article proper. - ¡Ouch! (^{hurt me} / _{more pain}) 12:47, 2 September 2011 (UTC)

Costs

Some quick calculations:

33,201.1295 kg (weight of 20 ft x 1 ft tungsten rod)

Rod Cost: $1,660,056 Launch Cost: $142,134,035 ($4281 per kg, double for usa launch)

Impact energy: 1344640500000 Joule

0.321 kilotons of TNT (vs 13 kt Hiroshima) — Preceding unsigned comment added by 174.24.156.53 (talk) 05:28, 9 December 2011 (UTC)

Mass of projectiles

The article's claim that the energies involved could rival small nuclear weapons seems very far-fetched. If I'm doing the math right, moving at 9 km/sec (LEO velocity) you would need a mass of over 100 tons/projectile to achieve a "yield" of even 1 kiloton. —Preceding unsigned comment added by 98.180.28.18 (talk) 03:29, 5 June 2009 (UTC)

Agreed. 1 kiloton of TNT has a yield of 4.184 x 10^12 J (according to the TNT_equivalent wiki article).

${\begin{aligned}E_{k}&={\tfrac {1}{2}}mv^{2}\\&={\tfrac {1}{2}}(100000~{\mbox{kg}})(9000~{\mbox{m/s}})^{2}\\&=4.05\times 10^{12}{\mbox{J}}\end{aligned}}$

Ergo, the energy of a 100 ton projectile traveling at 9 km/s is about that of one kiloton of TNT. -- Kargoneth (talk) 04:33, 26 October 2009 (UTC)

I think that not the overall energy was said(in the original source) to be comparable, but the amount of energy which strikes the target. Nukes are more powerful, but a direct kinetic hit might have an equal "energetic density", i.e. if they are 1/1000th as powerful, but 1000 times as concentrated (in that most of it would hit a very small area) as well.

As a rule of thumb, a mass moving at 10,000 feet/s or 3km/s has a kinetic energy equivalent to the explosive energy of TNT. User.Zero.Zero.Zero.One (talk) 10:59, 2 November 2010 (UTC)

Fiction section

Halo2 and Red Lightning references should probably be removed, or moved to the relativistic bombardment/RKV article, because these are projectiles moving at 40% SoL(Halo2) or even "near" speed of light, whatever that means. That's relativistic bombardment. While they are certainly an extreme case of kinetic bombardment, they differ from the more conventional kinetic bombardment in two ways: (1) even small projectiles (needle to arrow-sized) carry kinetic energy comparable to today's nuclear weapons, and (2) they don't gain most of their energy from the height difference while deorbiting an earth-sized body (or any planet for that matter). Most importantly, the Halo2 concept of Super MACs uses slugs that heavy (100s of tonnes, exact figures are in the RKV article) and fast (40% SoL IIRC) that an impact near low earth orbit would result in collateral damage on earth's surface. Not to mention recoil. One shot would propel a Super MAC station backwards at 60 m/s even if we assume a 500t projectile and a station weighing one billion tonnes. User.Zero.Zero.Zero.One (talk) 10:59, 2 November 2010 (UTC)

If these are to be moved then the Honor Harrington stuff should go with them. Even at the start of the series a burnt-out missile would hit at a few percent of lightspeed and by the current state of combat it's up past 80% of lightspeed. Loren Pechtel (talk) 23:27, 2 March 2012 (UTC)

Citation needed?

"One drawback of the system is that the weapon's sensors would almost certainly be blind during atmospheric reentry due to the plasma sheath that would develop ahead of it, so a mobile target could be difficult to hit if it performed any unexpected maneuvering.[citation needed] " Isn't this self-evident? Basesurge (talk) 22:05, 4 December 2010 (UTC)

No, definitely needs a citation. Only in very clear cases of common knowledge are citations not needed. This isn't one of them. --Leivick (talk)

hitting a moving target whilst blind is hard needs a citation? 01:57, 5 December 2010 (UTC)

If it was self-evident, then the world wouldn't see so many popular misconceptions. Even Jerry Pournelle, the man who helped to invent THOR, failed to publicize the problem. Read *Footfall* and you'll get a description of an anti-tank crowbar with an electro-optical sensor mounted right at the nose, right where the worse of the air friction and compression would be.--Woerkilt (talk) 19:14, 29 January 2012 (UTC)

I propose amending the entry in the article to read, "One drawback of the system is that any forward-looking sensors on the weapon would be blinded, if not actually destroyed, by air friction and compression. A manuevering target would be unlikely to be hit." To support this statement, use the same sources cited in the articles on atmospheric re-entry, where the effects of re-entry on the forward parts of the vehicle, and the optimal re-entry designs are discussed. Also, I've found a Union of Concerned scientists booklet that I am studying, since it seems to discuss orbital warfare. I'll get back you guys on that. Finally, I would look into any sources about the feasibility of using gyroscopes for ballistic aiming, or a tail-mounted transciever to allow an indirect active guidance via a spotting satallite.--Woerkilt (talk) 19:14, 29 January 2012 (UTC)

"The time between deorbiting and impact would only be a few minutes, and depending on the orbits and positions in the orbits, the system would have a world-wide range.[citation needed] " Surely this is blatantly obvious to *anyone* who knows *anything* about orbital mechanics? — Preceding unsigned comment added by 83.222.52.18 (talk) 15:49, 18 November 2011 (UTC)

The encyclopedia is intended for people who don't know much about the subject they're reading about; that's why they're reading the article. Moreover imprecise statements like "a few minutes" are just the kind of thing a decent reference, from a reliable source, will avoid - it's not clear whether "a few" means "two" or "twenty". -- Finlay McWalterჷTalk 16:27, 18 November 2011 (UTC)

And remember that the intended audience for an article can be very wide. For this one it might be a 10 year old who just played Fallout 3 and wants to know if Highwater-Trousers has any credibility, or a history graduate working in public policy who is researching the defence policy implications of space weaponisation, or a journalist reacting to an announcement that some government has deployed some device that might resemble Thor. None of these people can be expected to have a clue about orbital mechanics, and we don't exclude them just because it's supposedly obvious to someone who does. -- Finlay McWalterჷTalk 16:31, 18 November 2011 (UTC)

If it was blatantly obvious to anyone who knows anything about orbital mechanics, then the article would not hold to the vague statement of a "few minutes" or a "world-wide range". A bunker-buster THOR projectile, approximately 20 meters long by one meter in diameter, will take a minimum of 30 minutes using the fastest feasible delta-v. This is according to calculations some engineering students made for me. We determined that using a more gradual perigree intersection will take a minimum of 45 minutes. None of this includes the time it takes to actually get the launch platform on station for the appropriate launch window. Because those windows of opportunity are limited, a network of THOR systems will be required for world-wide coverage. I propose the statement in the article to be ammended--once appropriate sources are found--to something like, "The time between deorbiting and impact is comparable to an ICBM at 30 to 45 minutes [or whatever the sources actually specify]. A network of THOR systems could provide global bombardment coverage."--Woerkilt (talk) 19:14, 29 January 2012 (UTC)

Lead paragraph may suggest it is a currently used tactic

The lead phrase "A kinetic bombardment is the act of attacking a planetary surface with an inert projectile" kind of suggests it is something that has been used in the past, or is currently deployed. Obviously this idea is refuted by the rest of the article, but nonetheless would it be worth including some more clarification that this is a theoretical and sci-fi concept rather than something used currently?

Even using the phrase "A kinetic bombardment is the hypothetical act of attacking a planetary surface with an inert de-orbited projectile" or something similar, would clarify it without much changing the substance of the lead. Any thoughts about this? — Preceding unsigned comment added by OneCatch (talk • contribs) 15:04, 1 June 2013 (UTC)

references in sci-fi

Maybe worth looking into, I'm fairly certain that the first ever reference to Orbital Kinetic Strikes in any videogame was in Tom Clancy's Endwar — Preceding unsigned comment added by 74.75.60.225 (talk) 22:30, 19 May 2014 (UTC)

The concept, using a smaller caliber to kill human targets, is also used in the 1989 Wim Wenders film The End of Violence. Better the devil you know than the devil you don't. (talk) 21:23, 10 September 2022 (UTC)

Some common sense ideas regarding Rods from God

I would like to make some simple observations that might contribute to discussions regarding this topic.

1. One major criticism with this kinetic concept as one comment here at WIKI TALK explains with math is that free fall from space will not allow a usable object (perhaps a one ton pole) from obtaining sufficient energy to destroy an imagined underground target. It is therefore necessary to add to descent speed with additional energy via rocket propellent (which would add to the overall weight)

2. Such an external (and aft placed) booster could also supply some steering via the mode being tested on the X 51 project for a hypersonic missile. I think this would at least allow the mathematics of the energy released to be sufficient for the weapon's intended purpose --which is to destroy deeply buried targets. I note the Nike anti-nuke defense systems (via Hercules boosters) from the 1970s could lift (against gravity) payloads in seconds to significant mach speeds. Such filmed launches can be seen on open sources. It would not be very difficult to accelerate the rod downward faster than free fall.

3. The next BIG question is how such a fast moving object would react upon striking the earth's surface. Would not rail gun tests scaled down to size show us what happens? Forgive the pun, but this is not rocket science. Some scientists claim such speeds would result in the rod being vaporized and the energy converted into undamaging heat. What is the proof? Others claim extremely fast objects of moderate size have struck the moon leaving craters. Determining what actually happens should not be beyond the realm of experimentation. It might be found that the concussion downward would have a devastating effect. Our own super MOABs which the US has threatened to use on Iran's Fordow achieves its lethality in the explosion, not driving mass downward.

4. Another criticism is that traveling at such hypersonic speeds would melt the rod. Perhaps ceramics could be effective on the rod's surface. Theoretically perhaps, an artificially generated plasma (a different technology that has yet to be demonstrated so I won't go into here) could keep the thermal heat a safe distance from the rod's surface. This might allow a range of metals that could be used for such rods. Tungsten is expensive. In any case, I am not making an economic case for building a rod weapon beyond the consequences an enemy's deeply buried site presents in the long term. In any case, the thermal problem is being addressed in the US hypersonic project and appears not to be a deal breaker. Again, rail gun tests should be able to shed some light on the thermal and impact issues.

5. Would the heat generated at plus mach 20 speeds cause a fusion reaction with atmosphere? I have no clue but I rather doubt looking at the rods coming down might not be a good idea.

6. In theory, a SpaceX plane could lift off with two rods to a high altitude. Boosters could take each into LEO. Small thrusters could change orbits and initiate return. There appears no greater cost to this transport than the planned entertainment of commercial travelers on Virgin.

I think the above moves us past the usual gridlock in the debate of this topic......

Maxtrue (talk) 15:49, 23 April 2015 (UTC)

Please read The Wikipedia Talk Page Guidelines. This page is not for the discussion of kinetic bombardment in general, but for discussions about ways to improve the article Kinetic bombardment. While it certainly is an interesting topic, it's just not appropriate to talk about it here. Unless you're proposing changes to the article, there's really no justification for this. MjolnirPants Tell me all about it. 12:37, 24 April 2015 (UTC)

Use of "brake" in the opening paragraphs

While not technically incorrect, the use of the word brake in this context is highly confusing. In order to more accurately convey the intended meaning of slowing the object to de-orbit, I would suggest using a synonym or rewording the sentence. The fact that there is a note in the edit page explaining the intended meaning seems to support the need for the change. — Preceding unsigned comment added by 8.39.233.12 (talk) 17:50, 6 August 2015 (UTC)

"...not technically incorrect..." is synonymous to "technically correct." The purpose of WP is to inform, something which we can't do well if we avoid using technical language. If you want to add an explanation of the word, by all means go ahead. But don't remove the word, as it's used widely in orbital dynamics to refer to exactly that. MjolnirPants Tell me all about it. 18:34, 6 August 2015 (UTC)

As I understand it, a body can either enter a brake orbit (noun - an orbit starting with zero initial velocity) or break orbit (verb - to leave an orbit). Which is intended I have no idea. I'll leave it to you to edit or not. — Preceding unsigned comment added by 8.39.233.12 (talk) 20:20, 6 August 2015 (UTC)

Not trying to be insulting, but in that case your understanding is shockingly limited.

http://dictionary.reference.com/browse/brake Note the 'verb' entry directly below the noun. One can brake in a wide variety of situations, including orbital dynamics. To say that it 'breaks' a rod out of orbit is almost nonsensical and more than a little vague, while to say that it 'brakes' the rod out of orbit is to inform the reader that it actively decelerates the rod such that it falls out of orbit. Again, if you don't think it's clear enough, add an explanation. I, for one, am happy with it the way it is. MjolnirPants Tell me all about it. 21:04, 6 August 2015 (UTC)

You show me one instance in the literature that uses the phrase "brake [insert object here] out of orbit" or similar in the context you mean it and I'll concede the point. The phrase as it stands is neither grammatically nor technically correct.

https://books.google.com/books?id=pjiuMbDxsJIC&pg=PA107&lpg=PA107&dq=%22brake+out+of+orbit%22&source=bl&ots=Uo1gpLSLUA&sig=XFplYY9iJuA6yNSQZee8Tr0C0RE&hl=en&sa=X&ved=0CCEQ6AEwAGoVChMImvqnjfqWxwIVyx0-Ch2jfgFU#v=onepage&q=%22brake%20out%20of%20orbit%22&f=false You have absolutely no idea what the hell you're talking about. MjolnirPants Tell me all about it. 12:22, 7 August 2015 (UTC)

Alright, I stand corrected. I would suggest a citation be put in the article to clarify the terminology with no further edit.

By the way, on a personal note. If you intend to continue to be a regular contributor, try to keep this more professional. Personal attacks are never helpful. Everybody's goal here is to provide correct and clear information. I expressed a concern. You provided information addressing that concern. That's all that was needed. I'm not afraid to be wrong and I won't be bullied into a consensus. — Preceding unsigned comment added by 8.39.233.13 (talk) 14:24, 7 August 2015 (UTC)

Did you really just accuse me of being a bully in the same comment in which you chide me for a (nonexistent) personal attack? Yes, you did. On that note, I'll bid you happy editing and be on my merry way. MjolnirPants Tell me all about it. 21:03, 7 August 2015 (UTC)

As a note to any future readers. I have taken this off-line to prevent any unnecessary back and forth. — Preceding unsigned comment added by Myth318 (talk • contribs) 02:28, 8 August 2015 (UTC)

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