F-35 Is Newest Thorn In North Korea’s Side

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steve2267

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Unread post07 Jan 2018, 02:38

arian wrote:
steve2267 wrote:
arian wrote:Are you seriously suggesting F-35 and AIM-120 can intercept ballistic missiles?

Come on now. That's not even science fiction.


Yes. It was discussed fairly extensively a week or two ago. Where've you been?


Well I can't keep up with everything. I'm glad it's been discussed however and that at least we're not claiming that. Your post, however, read as if there was some technical possibility of doing so if it weren't for the missile flying over China or Russia. I don't think there's any technical possibility of doing so at all.


I simply disagree with you. As I discussed here, viewtopic.php?p=382962#p382962, back-of-the napkin calculations seem to indicate that an F-35 within 60-80nm *downrange* of a launch site should be able to easily intercept a climbing, liquid fueled ICBM in the first minute and a half flight (two minutes tops). Much beyond T+90sec, the missile will be too high, climbing too quickly. IMO, for this to work, the F-35 would need to be between 30-50,000ft. The higher the better. IMO, the biggest unknown is the guidance algorithm and kinematic performance of the AIM-120. That being said, the ICBM is 1) not evasive (other than accelerating and climbing) and 2) makes a big, fat, easily tracked target and 3) is pretty "fragile" compared to a bomber or other large aircraft. This intercept should potentially be doable from some crossrange distance (to the sides of the ground track), though how far I am unsure.

If an F-35 detected a launch and fired an AIM-120 @ T+15sec, and interception took place at T+75sec, then the AIM-120 should cover ~49nm in 60sec, and the missile will have traveled approx. 16nm downrange. If the F-35 was downrange of the launcher, then it could potentially intercept a launch on the order of 65nm away. Analysis of Titan II trajectory data reveals that the missile will be travelling somewhere between M2.1 and M3.7, in a very predictable manner.

Are you stating, arian, that this is outside the intercept parameters of an AIM-120C7?

So technically, within the first 90sec of launch, yes, I think it is technically feasible to intercept a liquid fueled ICBM on the order of performance of a Titan II. But IMO, the launch constraints of being within ~65nm downrange of a launch site and not too far crossrange of the ground track, makes this intercept for all practical purposes, tactically unsound.


arian wrote:F-35's role in ballistic missile defense might be in deploying its IR sensor to detect launches before the missile raises to radar horizon (for ships, for example), and thus giving you a few extra seconds of warning. And also in detecting the launch location and retaliating quickly.

Other than that, if these Nork missiles are liquid fueled and take time to prepare and fuel, the F-35s long-range SAR and optical detection capabilities might give you an advantage in detecting the launch site before it fires off from maybe 100+km away and attack the site before launch (if weapons allow and can get there before launch).


Nor arguments with any of these points. Hitting liquid fueled ICBMs on the ground would be best, and something the F-35 seems well suited to do. As the Northrop Grumman press releases have stated, using DAS / EOTAS to detect launch and pass targeting track data up the kill chain would seem to be very doable. But do we have the aircraft to try to fly a 24x7 Missile Cap off of NORK? Hopefully some enterprising manager has already sold the USG on the idea and they have the F-35 DAS flying on a stealthy, high flying UAS right now slightly east of NORK.

arian wrote:All too "iffy".


Oh, I see. I thought at first you were questioning whether technically an F-35 could intercept a liquid fueld ICBM. I explained the technical parameters in which I think an intercept could occur, but now you are going all "iffy" on me. So you seem to admit that it would, technically, be possible.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post07 Jan 2018, 03:07

steve2267 wrote:I simply disagree with you. As I discussed here, viewtopic.php?p=382962#p382962, back-of-the napkin calculations seem to indicate that an F-35 within 60-80nm *downrange* of a launch site should be able to easily intercept a climbing, liquid fueled ICBM in the first minute and a half flight (two minutes tops). Much beyond T+90sec, the missile will be too high, climbing too quickly. IMO, for this to work, the F-35 would need to be between 30-50,000ft. The higher the better. IMO, the biggest unknown is the guidance algorithm and kinematic performance of the AIM-120. That being said, the ICBM is 1) not evasive (other than accelerating and climbing) and 2) makes a big, fat, easily tracked target and 3) is pretty "fragile" compared to a bomber or other large aircraft. This intercept should potentially be doable from some crossrange distance (to the sides of the ground track), though how far I am unsure.

If an F-35 detected a launch and fired an AIM-120 @ T+15sec, and interception took place at T+75sec, then the AIM-120 should cover ~49nm in 60sec, and the missile will have traveled approx. 16nm downrange. If the F-35 was downrange of the launcher, then it could potentially intercept a launch on the order of 65nm away. Analysis of Titan II trajectory data reveals that the missile will be travelling somewhere between M2.1 and M3.7, in a very predictable manner.

Are you stating, arian, that this is outside the intercept parameters of an AIM-120C7?

So technically, within the first 90sec of launch, yes, I think it is technically feasible to intercept a liquid fueled ICBM on the order of performance of a Titan II. But IMO, the launch constraints of being within ~65nm downrange of a launch site and not too far crossrange of the ground track, makes this intercept for all practical purposes, tactically unsound.


I don't buy it. It doesn't take 15 seconds to start and engagement on such a target. We've seen this video:
https://www.youtube.com/watch?v=qF29GBSpRF4

It took about 24-25 seconds before F-35 got a radar track on missile. It can be more depending on other factors. Add a few more seconds to actually start engagement. Obviously under very ideal conditions with the plane in exactly the right spot and the pilot exactly ready to engage. If you have a 90 second window you absolutely do not have enough time to complete an intercept. Not even close.

And your calculations of the distance traveled by AIM-120 is based on a constant Mach 5 speed flight. I'm guessing the missile needs time to accelerate, and take into account the altitude it needs to raise at etc. AIM-120 doesn't even have that high of a max speed.

In my opinion, there's a zero chance.

Oh, I see. I thought at first you were questioning whether technically an F-35 could intercept a liquid fueld ICBM. I explained the technical parameters in which I think an intercept could occur, but now you are going all "iffy" on me. So you seem to admit that it would, technically, be possible.


The iffy part is all the other stuff I said, like being able to detect the launch preparations, in time, and actually being able to engage the launcher before launch. All depends on how long it takes to fuel and ready the missiles, where the F-35 is located, where the launcher is located and how well the whole process is camouflaged, and the weapon's ability to get there and get there on time. Too many variables which can go wrong on a time sensitive target and hence an unreliable means of defense.

As an early warning platform, yes. But then the engagement is left to ballistic missile defense assets.
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Unread post07 Jan 2018, 05:54

arian wrote:And your calculations of the distance traveled by AIM-120 is based on a constant Mach 5 speed flight. I'm guessing the missile needs time to accelerate, and take into account the altitude it needs to raise at etc. AIM-120 doesn't even have that high of a max speed.


Yes, I ignored acceleration. I felt that was reasonable given how quickly AIM-120's accelerate away from F-35's. They move out sharply. And my distance calculation was based on an average velocity of Mach 4 (4 * 589 kts) which seems reasonable for 30,000+ ft. In addition, I specified that the F-35's would be at 30-50,000ft, preferably the latter, so the "altitude it needs to raise" is builtin. For back-of-the-napkin calculations, I feel my assumptions are reasonable and accurate.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post07 Jan 2018, 06:04

steve2267 wrote:
arian wrote:And your calculations of the distance traveled by AIM-120 is based on a constant Mach 5 speed flight. I'm guessing the missile needs time to accelerate, and take into account the altitude it needs to raise at etc. AIM-120 doesn't even have that high of a max speed.


Yes, I ignored acceleration. I felt that was reasonable given how quickly AIM-120's accelerate away from F-35's. They move out sharply. And my distance calculation was based on an average velocity of Mach 4 (4 * 589 kts) which seems reasonable for 30,000+ ft. In addition, I specified that the F-35's would be at 30-50,000ft, preferably the latter, so the "altitude it needs to raise" is builtin. For back-of-the-napkin calculations, I feel my assumptions are reasonable and accurate.


My back of the envelope calculation says that 45nm in 1 minute is Mach 5.1.

The biggest issue I think is that you're assuming the F-35 is at exactly the right position in exactly the right orientation and altitude and speed at exactly the second the missile is fired. Even if all the other factors you assume were correct (which I don't think they are as there's no way the F-35 would be able to react that fast), this one is very unlikely. I'm sure you would acknowledge that it is very unlikely that you'd be there at the right time.
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Unread post07 Jan 2018, 08:43

ok guys, maybe the PDF below will help all of you discussing this topic.

AIM-120C-5 Performance Assessment for Digital Combat Simulation Enhancement
http://www.zaretto.com/sites/zaretto.co ... t-rev2.pdf
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Unread post07 Jan 2018, 08:47

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Unread post07 Jan 2018, 18:16

arian wrote:My back of the envelope calculation says that 45nm in 1 minute is Mach 5.1.

D*mn napkin. I found my mistake. Embarrassing really.

49nm is covered at Mach 4.0 in 75 seconds. In my "example", I assumed AIM-120 launch at T+15sec, and intercept at T+75sec. So the AIM-120 only had 60sec to intercept. So knock 10nm off all my range numbers.

arin wrote:The biggest issue I think is that you're assuming the F-35 is at exactly the right position in exactly the right orientation and altitude and speed at exactly the second the missile is fired. Even if all the other factors you assume were correct (which I don't think they are as there's no way the F-35 would be able to react that fast), this one is very unlikely. I'm sure you would acknowledge that it is very unlikely that you'd be there at the right time.


Perhaps I did not write clearly enough. I thought I did. Technically, I believe an F-35 could intercept a liquid fueled ICBM within the first 90sec of flight. 90sec is pushing it. 75sec seems technically possible.

Is this practical? Is it tactical? No. Not hardly. For the reasons you point out as well as many others I had stated. I thought I had made that clear. I guess not.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post07 Jan 2018, 18:25

As our "Minuteman III" has a listed speed of 17,000 + speed at 700 miles, what is the acceleration rate of a "typical" ICBM? I'm no mathematician, but mach 23 at 700 miles looks quick, and that's vertically. that means that if not caught at launch, you'd be chasing an accelerating icbm vertically.
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Unread post07 Jan 2018, 18:37

tailgate wrote:As our "Minuteman III" has a listed speed of 17,000 + speed at 700 miles, what is the acceleration rate of a "typical" ICBM? I'm no mathematician, but mach 23 at 700 miles looks quick, and that's vertically. that means that if not caught at launch, you'd be chasing an accelerating icbm vertically.


I specifically restricted my napkin to liquid fueld ICBMs 1) to see if an intercept by an AIM-120 might be even possible at a "tactically significant" range. I started at 100nm, compared guestimated AIM-120 flight time to a Titan II trajectory (slow burn, and fast rise burn), and deduced that if an intercept does not occur within T+90sec, more like T+75sec, the missile will be too high (and travelling too fast) to make an intercept. It appeared (to me anyway) that an AIM-120 intercept might be possible within approx 65nm of an F-35 position, with the F-35 downrange of the launch site.

Solid fuel ICBMs get out right quick, esp. compared to a liquid fueled rocket, and if such an intercept is possible, I am swagging that it would have to occur very soon after launch -- within T+30sec? I don't have access to, nor did I search for, Minuteman III trajectory data. I was primarily looking for trajectory time vs. altitude data to judge whether an intercept might be possible.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post07 Jan 2018, 18:51

Greets, thanks for the info! I would dare say you would have to be right there at launch within your window to even have a chance I guess.......
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Unread post07 Jan 2018, 19:11

tailgate wrote:Greets, thanks for the info! I would dare say you would have to be right there at launch within your window to even have a chance I guess.......


I agree. It appears to NOT be tactically relevant. Add to the fact that trajectories targeting Los Angeles or Washington DC pretty much fly inland over China (PRC) and/or Russia, I don't think you could fly F-35's in international airspace with much chance at all (virtually nil, if even that) of making an intercept. That doesn't even account for how many aircraft you might need to put up a 24x7 missile CAP... tanker support etc.

If one were to consider putting $$ into such an early boost-phase air-to-air intercept concept, it would seem to me you need to put funding into:
  • high-altitude (60-70,000ft), long endurance, stealthy UAS airframe with an integrated DAS / LPI AESA radar (e.g. APG-81) + LPI datacomm link (e.g. MADL)
  • a new hypersonic, long range A2A missile

I wonder if the B-21 might fit the bill? But this thing has to be pretty much guaran-damn-teed radar invisible. Loitering such a vehicle over a sovereign nation's airspace probably would not go over very well with any nation.

Some have suggested some sort of long range, hypersonic booster for a CUDA-like endgame, hit-to-kill missile to conduct the actual intercept. I wonder if it might not be cheaper in this fantasyland to simply figure out how to carry and air launch an SM2-Blk3B missile? Maybe the booster motor could be cut down since you'd be launching at 60-70k' MSL rather than at sea level. Dunno. Someone probably has a contract somewhere to analyze this stuff.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post07 Jan 2018, 19:22

Agree, I think you have it right with the "flight paths" though. Another would just be the outright speed you are dealing with.

How fast can we detect a launch? can we even detect immediately from the launch pad, that would even moreso put into doubt an intercept.
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Unread post07 Jan 2018, 20:19

tailgate wrote: How fast can we detect a launch? can we even detect immediately from the launch pad, that would even moreso put into doubt an intercept.


That is a key question. In good air (e.g. no clouds / visible moisture), I would surmise DAS would detect a missile plume near instantaneously -- under a second, anyway. I have little training, knowledge, or experience (TKE) with IR detection. I know you have short, mid, and long-wave infrared detectors. I do not know off the top of my head what DAS consists of, nor do I know to what extent visible moisture (fog, clouds etc) affects them. Some wavelengths are more immune to visible moisture interference. But, say, from a 30-50k ft altitude, with no visible moisture, I would think DAS detection of a launch plume is near instantaneous. Ditto for a radar track via APG-81 if it is actively scanning and the missile is within the radar search window as I am not aware of any "stealth" ICBMs, certainly not in the boost phase. The bigger question is how long does it take for the F-35 fusion engine to pull together other sensor data, evaluate the different data streams, and then classify the ICBM track as a bogey, and also as a missile, as opposed to a ground or air vehicle.

Once identified as a threat missile (ICBM), some (as yet possibly unwritten) computer routine could determine if this F-35 has a firing solution on the ICBM, or if another F-35 within it's local "net" has a possible firing solution. All of this data and/or information, I imagine, would be shared with neighboring F-35s.

Perhaps the greatest advantage of the F-35 is in the SA it brings to the battlefield, not only to each individual pilot, but also the flight, and all neighboring units tied into its "net." As such, the ISR capabilities of the F-35 may be its most important feature in an anti-ICBM role. However, if you have several flights of F-35 in an area executing a mission, and one detects an ICBM launch, it may be possible that another F-35 could be in a (much better) position to execute an intercept with an AIM-120 (or maybe a Meteor or even an AIM-9X). So if you have F-35s conducting a strike mission, or are "Scud-hunting" ala the Gulf War, then while they are searching for ground targets or prosecuting known ground targets, if one detects a launch signature, and they are in position to take out the climbing ICBM, then I consider that a "bonus." Dilly dilly.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post07 Jan 2018, 20:25

And I have to ask.....would firing like from a silo or deep vally hide the signature long enough to thwart such an attempt. lol
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Unread post07 Jan 2018, 20:40

tailgate wrote:And I have to ask.....would firing like from a silo or deep vally hide the signature long enough to thwart such an attempt. lol


I have no idea. That would have to be accounted for in a trade study. My inclination is to say no, in the case of a liquid fueled booster. I am already discounting the possibility of intercepting a solid fueled ICBM. I suspect they just gain altitude too quickly.

In the case of a liquid fueled ICBM, and a silo, the exhaust plume from the rocket motor would be a significant, detectable IR event even before the missile emerges from the silo. Find a video of a Titan II launch (or even a Minuteman) -- you have a huge exhaust plume emerging from the silo vents before the missile appears.

In the case of a "deep valley"... how deep is the valley? Looking at the Titan II trajectory data to which I linked earlier... at T+10sec, the vehicle is somewhere between 2-400m altitude, so ~660-1320ft altitude, and it has taken on the order of 10sec detectability away from an intercept. So maybe that decreases an intercept attempt by some 7nm?

Something else to consider, in the case of NORK, I would be surprised if the US doesn't have NORK blanketed by older DSP or newer SIBR's satellites -- basically a huge IR staring eye-in-the-sky. The question I would ask is how long does it take for DSP/SIBRs to detect and classify a launch? How long to notify F-35's or other assets in the immediate vicinity of a launch threat and effect an intercept attempt? I suspect detection is on the order of seconds, confirmation is on the order of seconds - tens of seconds, and networked notification is on the order of tens of seconds to minutes. I suspect there is too much lag or "slop" in the internetworked comms to make this effective. But a proper system-of-systems trade study might reveal otherwise.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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