Talk:Kinetic bombardment

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

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://en.wikipedia.org/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)

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)

This article need some substaintial technical clarification, because it reads far too pat to be true.

• Rods from God do have to be de-orbited, likely with a detectable amount of energy, in order to overcome angular momentum. One can't just "drop" them or "nudge them" in the right direction. Such a manuver might require several burns, totaling a minute or more of detectable infrared signatures.
• In any event, the projectile will lose velocity to atmospheric drag, generating a sustained IR signature like a tracer bullet in the atmosphere. Such projectiles would also likely appear on magenetic anomally detectors. Don't forget that an infrared/ionization bloom can be detected on radar, too.
• Besides, to maintain the kind of speeds discussed by many novelists and theorists--namely a projectile coming all the way down 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.
• Fortunately, a projectile does not need to be traveling at orbital velocity to make a big impact. A dense or massive projectile, that has been accumulating knetic energy as it falls hundreds of kilometers, will transfer plenty of energy at a liesurely Mach 10.
• Finally, as Rods from God are probably released from an altitude considerably higher than an ICBM (because you gotta protect your launch platform from anti-sat missiles, casual observation, and orbital decay), it will take tens of minutes, if not an hour or more to descend to the surface. This time could actually be in the projectiles' favor, as long as it doesn't slow down too much, because it when it finally hits it'll make a big ol' THUMP!
• On the other hand, re-entry time probably precludes this weapon from being used as a pre-emptive strike against enemy ICBM bunkers, since they'll have time to get a lot of birds in the air unless re-entry can be camoflagued. More study on this is required.

Such a projectile would also need some sort of heat shield to preserve the projectile and it's control surfaces--not just from the inital entry, but from the immense friction generated by the lower 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, stands a good chance of shattering a space-born projectile.

Finally, such a projectile is not going to be self-guided as Jerry Pournelle and other authors like to imagine. Such a sensor is A) spendy, B) has to be covered by a heat/friction shield, C) will be obscured by the ionization of re-entry and D) is unecessary.

• A Rod from God instead would function more like a GPS-guided weapon. It would have a sensor in the tail, protected from the heat and drag of re-entry, linked to a GPS sat. The sat tracks both the target and projectile telemetry, and transmits course correction data. This cuts down the cost and complexity of the projectile, since you just need a reciever or transciever slaved to control surfaces, like in a JDAM bomb.
• A good old fashioned ballistic re-entry might be the cheapest of all. Use a gyro to keep the projectile on trajectory. Such a system will drift, but probably will retain enough accuracy with modern electronics to wipe out an enemy airbase or tank depot.

That said, Rods from God strike me as being best used on fixed structures. The idea of dropping a bunch of "crowbars" from 600km (or even 300km) 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.--Woerkilt (talk) 05:14, 6 May 2009 (UTC)

A practical projectile, to put a final thought on my thoughts, is going to rely on mass as much as the velocity. A Tungsten Telephone pole is probably about as unecessary a material as DU is for any anti-aircraft gun. We don't use DU in the Navy CWIS systems because it is expensive, overkill, and reacts with the radio frequency energy that pools around the superstructure.

• Likewise, an orbital drop weapon can be made out of iron or nickel, mined from one of the hundreds of thousands of asteroids orbiting Earth--save the tungsten for your earthly needs!
• The projectile will probably be shaped like a Mercury or Apollo space capsule, with an ablative, low-cost heat shield on the underside, using the wide surface area to generate a protective shockwave. This eliminates the need to use exotic materials in the rest of body. A downside is the substantial IR and radar cross-section that will be generated, though at certain points the radar waves will probably be scattered instead of returning to the detector.
• A big lead weight, cored with iron and reinforced with a steel gliding jacket (plus exotic friction shield), dropped from 600 kilometers in the sky is going to make a hell of a crater and earth shocks. More than sufficient to collapse an underground bunker. It's not as sexy as a tungsten long-rod with an self-guidance head, but a big dumb weight taking orders from GPS is mucho cheaper and more practical to assemble and guide.

Also, consider something more like the Tunguska Event of 1908. You can have a projectile that is indeed designed to shatter in the lower atmosphere, as I complained about earlier. But instead of being a complaint, this is now a favor. If the energy of the shockwave ahead of the projectile can overcome the forces holding the thing together, it could explode quitely violently, producing heat and concussion on the order of an atomic bomb. This could be accomplished through careful areodynamic design, while the composition of the warhead is still basically a big hunk of iron, or nickel, or some similarly cheap composite.--Woerkilt (talk) 05:36, 6 May 2009 (UTC) Edited and revised for clarity--Woerkilt (talk) 23:52, 13 May 2009 (UTC)