Issues on Intercepting Hypersonic Missile.

Jeff Head said:

You know what Engineer...you have shown a proposenity for mis-communication and mis-understanding and then taking your mis-understanding and using it to insult the people you have mis-communicated with. It's getting rather tiring.

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Nope. I haven't misunderstood "The vessel need not be destroyed either. A simulated dummy warhead could easily be used that has the proper weight but no explosive."

Jeff Head said:

Clearly if the RV does not hit the vessel in such an exercise, or if it does not score a direct, kill hit, then the vessel may be re-used for the next exercise.

If it scores a direct hit, it is likely to sink the target vessel...but that is also not a 100% given, depending on the vessel, weight of the warhead, the design of the dummy warhead, final velocity, etc.

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Of course, I never said there is a 100% chance that a direct hit would sink the vessel. No need to take your misunderstanding and insult the people you have miscommunicated with. However, a direct hit will most likely damage the vessel so severely and make it written-off, as in too expensive to repair. Of course, if it is cheap enough, it could simply be sunk outright, but I really wonder if such a cheap converted could actually move at 30 kts to provide the "realistic" scenarios that you have demanded.

Jeff Head said:

So, here's some advise. It costs nothing, and it is entirely up to you as to whether you take it or not...but why don't you quit with the "no clue" insults and try and be a little more civil in your dialogue and communcation?

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If you have an affinity to take my posts as some form of insults, I can't stop you from that. All I can say is "all the more power to you".

Engineer said:

"The vessel need not be destroyed either. A simulated dummy warhead could easily be used that has the proper weight but no explosive."

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That statement is true. Does not have to be destroyed (as you yourself point out in your own post), and the warhead can be designed to have no explosives.

Engineer said:

Of course, I never said there is a 100% chance that a direct hit would sink the vessel.

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We agree...and if there is a chance that it would not be sunk, then depending, as I said before on the design of the warhead and the other things I mentioned, that conditions could extend all the way to a complete miss. The closer the exercise is to a complete miss, the greater chance there is of the vessel being reused. Nothing difficult to understand about that.

So you design your test target, in this case probably an older vessel with some modification and the necessary sensros, with all of that in mind..

Engineer said:

However, a direct hit will most likely damage the vessel so severely and make it written-off, as in too expensive to repair.

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Most likely means there is also a chance that it will not be (like it not being sunk either)...ergo, it could be reused if it does not damage it so badly that it has to be written off.

Engineer said:

If you have an affinity to take my posts as some form of insults, I can't stop you from that.

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You think you can tell someone that they have "no clue" about something you have been discussing with them and not have it taken as an insult? LOL, get a grip.

Adieu.

LOL... simply reusable? Quite clearly someone just has no clue as to how destructive a 100 kg mass (my assumption for the warhead's weight) at 7 km/s could be. You might want to find out how "Rods of God" would work.

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Someone, Engineer, needs to read the forum rules...

FORUM RULES: Things to Remember Before Posting, important, please read!

Posts containing personal attack, swearing, foul language, political propaganda, and commercial advertisement better know as spam.

Meaningless arguments and inappropriate provocation of other members.

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Knock off the under-handed insults and meaningless arguments.

bd popeye super moderator

Jeff Head said:

That statement is true. Does not have to be destroyed (as you yourself point out in your own post), and the warhead can be designed to have no explosives.

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Thus, there is no misinterpretation.

Jeff Head said:

We agree...and if there is a chance that it would not be sunk, then depending, as I said before on the design of the warhead and the other things I mentioned, that conditions could extend all the way to a complete miss. The closer the exercise is to a complete miss, the greater chance there is of the vessel being reused. Nothing difficult to understand about that.

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Of course, complete miss could be deliberate and intentional, too, which does not prevent one from analyzing how well all the system integrate together, nor prevent one from measuring the accuracy of the warhead. Thus, the possibility exists for the test to be carried out so the missile flies to Gobi desert instead of striking the ship.

Jeff Head said:

So you design your test target, in this case probably an older vessel with some modification and the necessary sensros, with all of that in mind..

Most likely means there is also a chance that it will not be (like it not being sunk either)...ergo, it could be reused if it does not damage it so badly that it has to be written off.

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Never said that isn't a possibility either, but it would be unlikely and depends largely on the size of the target and the amount of armor plus redundancies built in. It doesn't sounds cheap already. The bigger the target, the more localized the damage would be, but at the same time the cost would go up even more and the less chance it would be carried out. Most likely, the autonomous portion, propulsion, and sensors would have to be "suspended" or isolated to prevent damage due to the shockwave coming from the metal bulkhead. Finally, after all that, patching up the hole would be easy, fixing the stress permanently placed on the vessel will not.

Jeff Head said:

You think you can tell someone that they have "no clue" about something you have been discussing with them and not have it taken as an insult? LOL, get a grip.

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LOL... if you insist, then more power for you. But I will still suggest you to look up some videos from Kwajalein Atoll missile range to see the effects of an inert warhead at 7km/s.

bd popeye said:

Someone, Engineer, needs to read the forum rules...

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Right away!

Engineer said:

Certainly, the final test of the system as a whole should be as realistic as possible. However, there comes a point when it just isn't realistic to do a "realistic" test. Blindly trying to achieve "realism" means great resources are thrown to attempt to make the test as "real" as possible and one lose track of the actual objective -- which is the verification of the weapon.


LOL... simply reusable? Quite clearly someone just has no clue as to how destructive a 100 kg mass (my assumption for the warhead's weight) at 7 km/s could be. You might want to find out how "Rods of God" would work.

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The US Navy uses remote controlled, self propelled barges stacked with empty shipping containers that can take hits from missiles. It beats up the empty cans pretty good, but the barge is not usually affected. Empty shipping containers are cheap enough, there are stacks worn out cans at any decent sized port. There are also a variety of other remote controlled target craft used to simulate various fast attack craft. Some survive and some don't.



The barge in the above video is repaired after such hits and reused. Point Mugu and Port Hueneme ( pronounced Why-knee-mee ) have been doing this since WWII

Ambivalent said:

The US Navy uses remote controlled, self propelled barges stacked with empty shipping containers that can take hits from missiles. It beats up the empty cans pretty good, but the barge is not usually affected. Empty shipping containers are cheap enough, there are stacks worn out cans at any decent sized port. There are also a variety of other remote controlled target craft used to simulate various fast attack craft. Some survive and some don't.

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The barge in the above video is repaired after such hits and reused. Point Mugu and Port Hueneme ( pronounced Why-knee-mee ) have been doing this since WWII

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It is a very nice system for testing sea-skimming cruise missiles. The Harpoons shown in the video don't seem to been armed with a warhead, otherwise I have no doubt the barge would been sunk outright.

The PLAN does similar tests but uses a much smaller barge with radar reflector mounted on top. What would be the advantages or disadvantages of both methods?

Anyway, the trajectory of a sea-skimming cruise missile is different than that of a RV. The containers in the video acted like a sponge and absorb most of the kinetic energy from the missile. An inert RV, striking from above, would make short work of everything all the way down to the water, and the effect would be no different than a fully-armed Harpoon exploding inside the barge.

Re: Latest PLAN Aircraft Carrier Info & Photos

AssassinsMace said:

Trying to look for an article, I think it's in one of these forums, but there was one recently that mentioned that the ASBM could be capable of doing some bouncing-type maneuvering in the upper atomosphere to fool any BMD. There was graphic.



Here it is...

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The article talks about "gliding", but that is so misleading. There is almost no atmosphere in space, so gliding is impossible. The more correct terminology should be orbital maneuvers. There is no need to "maintain guidance" as the article has emphasized.

The bouncy trajectory should not be viewed as a trajectory, but rather, an orbit. Hohman transfer is often use to raise the altitude of orbit. To perform such a transfer, one basically fires the engine at no place other than the perigee and apogee -- two points of an orbit that is closest and furthest from the Earth's center. It is the most efficient method possible to change an orbit.

Of course, firing the missile's engine off apogee will no longer be considered as Hohmann transfer, but doing it very close to the apogee and one can still gain an efficiency advantage. In the case of the graph, the engine is fired for a brief period just beyond apogee. This creates a new apogee ahead of the missile to take advantage of. The engine fires again for a brief period beyond the second apogee, which creates a third apogee ahead of the missile.

Essentially, this improves the efficiency of the missile by artificially creating a series of apogee for Hohmann transfers. For the same missile, let say DF-31, flying a standard trajectory and the maximum range would be 8000km. Flying the new trajectory however, could increase the range to 12000km.

Of course, there are some draw backs. To take advantage of this, the missile having solid fuel will either need to have three stages, or two stage with the second stage being liquid engine. But I am almost certain that the latter will be used, since a liquid engine allows one to turn on or turn off the engine at will, offering more flexibility for the user and unpredictability for whomever on the receiving end.

Re: Latest PLAN Aircraft Carrier Info & Photos

Engineer said:

The article talks about "gliding", but that is so misleading. There is almost no atmosphere in space, so gliding is impossible. The more correct terminology should be orbital maneuvers. There is no need to "maintain guidance" as the article has emphasized.

The bouncy trajectory should not be viewed as a trajectory, but rather, an orbit. Hohman transfer is often use to raise the altitude of orbit. To perform such a transfer, one basically fires the engine at no place other than the perigee and apogee -- two points of an orbit that is closest and furthest from the Earth's center. It is the most efficient method possible to change an orbit.

Of course, firing the missile's engine off apogee will no longer be considered as Hohmann transfer, but doing it very close to the apogee and one can still gain an efficiency advantage. In the case of the graph, the engine is fired for a brief period just beyond apogee. This creates a new apogee ahead of the missile to take advantage of. The engine fires again for a brief period beyond the second apogee, which creates a third apogee ahead of the missile.

Essentially, this improves the efficiency of the missile by artificially creating a series of apogee for Hohmann transfers. For the same missile, let say DF-31, flying a standard trajectory and the maximum range would be 8000km. Flying the new trajectory however, could increase the range to 12000km.

Of course, there are some draw backs. To take advantage of this, the missile having solid fuel will either need to have three stages, or two stage with the second stage being liquid engine. But I am almost certain that the latter will be used, since a liquid engine allows one to turn on or turn off the engine at will, offering more flexibility for the user and unpredictability for whomever on the receiving end.

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One glaring inaccuracy in the article is mention of IR terminal homing. Without giving away specific information, there are definite speed limits to what can be done with IR and IIR sensors in the atmosphere that limit the top speed of IR and IIR equipped systems. Exoatmospheric systems like THAAD are not so limited, but a re-entry vehicle will be moving far too fast in the atmosphere for IR or IIR guidance to be used. Beyond this, this paper hints the tremendous difficulty finding seeker dome materials that are transparent to both radar and IR wavelengths and then producing it.



Here is another interesting study on an older dome material. Note the apparent Mach 5 speed limit of this material, and mention of degredation of the IR properties of the material due to dome heating.

I am shocked about this talk of illuminators. I thought with the coming of PESA/AESA, there was no longer this division of detection,tracking,engagement/illuminator radars. The PESA/AESA would be able to perform all roles. In PESA it will be time-sharing, and in AESA, the radar surface itself can be divided into different spatial zones, with one set of TR modules performing detection, another zone tracking, another engagement/illuminator roles apart from provision for time-sharing.

A PESA could illuminate several tens of missiles by jumping its beam around, illuminating each missile for a few milliseconds. An AESA faced with a saturation attack could easily transition the entire radar surface area to illumination mode, and direct multiple beams on multiple incoming missiles and defeat all of them . I am sure a SPY-1 AEGIS radar with its large surface area could illuminate at least 20 missiles simultaneously and if it uses time-sharing mode as well, at least double that number.

Likewise, I am surprised that the FLAP LID B radar can engage only 12 targets at the same time.