It seems from a logical perspective that if something can intercept a small, speedy object like a missile, it should only be even better at intercepting something comparatively larger and slower like a warplane. (I’m referring to interceptors like PAC-3, THAAD, Arrow 2, and SM-3)
I know I’ must be oversimplifying things, but how good are PAC-3, THAAD, Arrow 2 and SM-3 when it comes to intercepting warplanes?
For certain values of good…
From the wikipedia page on the Patriot PAC-3 missile:
But Arrow, THAAD and Standard SM-3 are dedicated anti-ballistic missiles; their radars, flight trajectories and launchers are geared toward intercepting that sort of target.
In the case of Standard SM-3, I suspect that most ships probably have a very few SM-3 missiles, and a shitload of SM-2 anti-aircraft missiles, so not such a big issue anyway.
I couldn’t say for sure but I would guess a ballistic missile doesn’t dodge as much as a fighter jet or a bomber.
You beat me to it. ICBMs don’t make evasive maneuvers. Bombers, fighters, and transports can.
Actually, yes they can. See MARV
OK, but if an enemy Su-27 appeared, and there was nothing to shoot it down with except THAAD/PAC-3, how well would that work?
The Patriot platform was originally intended to be an anti-aircraft system, but was overhauled in 1988 to add tactical ballistic defense functionality. The timing was good - 2 years later, we were desperate to keep Israel out of the Gulf War and they were sick of getting SCUDs launched at them, so we “loaned” them a crap-ton of Patriots.
That war would have gotten very messy had the Israeli’s pursued their right to self-defense… it turns out not all of their neighbors have warm fuzzies for the Chosen People, and it could have turned into a regional meltdown.
Anti-aircraft and ABMs are designed and optimized for specific engagement envelopes. In some cases an anti-aircraft missile may have some limited ability against tactical ballistic missiles. Here is a video of an old Hawk missile intercepting a tactical ballistic missile:
In the opposite case some ABMs like PAC-3 may have limited capability against aircraft.
However intercepting a target inside the atmosphere is very different than outside the atmosphere, and typically missiles use specific guidance and homing technologies optimized for each case. The basic decisions are radar vs IR homing, aerodynamic vs reaction jets vs thrust vectoring for maneuvering, and explosive fragmentation warhead vs hit-to-kill.
IR homing is typically used outside the atmosphere since the space backdrop is only 3 degrees Kelvin – nearly absolute zero. Older IR-seeking missiles like Sidewinder simply followed a hot point source and did not image the target. By contrast ABM interceptors use staring IR focal plane arrays and form a 2D image of the target. They may have image recognition capability to screen out decoys. Here is a IR seeker image downlinked from a SM-3 ABM of its target right before impact: http://www.defenseindustrydaily.com/images/ABM_Target_Viewed_From_SM-3_Seeker_lg.jpg
IR imaging becomes much more difficult within the atmosphere due to heating, rain, clouds, etc. Radar homing is generally used within the atmosphere since it is less affected atmospheric conditions. However it is also less precise and usually radar-guided missiles use fragmentation warheads. The PAC-3 is a short-range endo-atmospheric ABM, so it uses ground-based radar guidance for the initial fly-out then switches to an on-board millimeter-wave radar for terminal homing. It is mostly hit-to-kill but has a small “lethality enhancer” which launches low-speed fragments just before intercept to improve its effectiveness.
In some cases the ABM is so optimized it probably has little capability for an endoatmospheric intercept of an aircraft, much less a missile. E.g, the SM-3 uses a unitary “hit-to-kill” kinetic warhead and uses infrared imaging once outside the atmosphere and the kill vehicle is not designed for maneuvering within the atmosphere.
THAAD has both high-endo and exo-atmospheric capability but it is not really designed for intercepting aircraft.
The SM-6 is designed as a dual-purpose missile with both anti-aircraft and ABM capability but it is probably less effective at each than a single-purpose design: SM-6 Can Now Kill Both Cruise AND Ballistic Missiles - Breaking Defense
Even within ABMs, they are designed for specific engagement envelopes. Just because a PAC-3 can intercept tactical ballistic missiles does not mean it can intercept an ICBM, even if within range. The ABM task is so difficult that generally the radar, processing, guidance, terminal homing and warhead must be specifically designed for for a range of velocities and target types. THAAD probably has some capability against ICBMs but how much is not publically known.
Just like a space launch may have a very small “launch window”, an ABM intercept has extremely tight constraints on launch and available divert capability to hit the target. In some cases they may require “off-board cueing” or a datalink from a remote radar site to help calculate the exact launch moment and initial fly-out guidance. The engagement velocities, timing and intercept requirements are so severe there simply isn’t enough propellent to fly around looking for the target.
The function of a MaRV isn’t really actively dodging interceptors (the MaRV is surrounded by a plasma sheath through most of reentry and has no direct awareness of incoming interception) as being able to fly trajectories and hit targets that could not be hit with a purely ballistic conventional reentry vehicle. By flying a varied trajectory, a MaRV may have a passive ability to make interception more difficult, but most practical interception methods attempt to hit modern reentry vehicles (vice a unitary threats like the Scud-based threats in Iraq) focus on trying to hit the threat in the mid-course regime (before the RV separates from the carrier vehicle) or early in post-seperation terminal phase near apogee when the RV has the lowest vertical speed.
The issue with using ABM systems for anti-aircraft purposes is that most anti-missile interceptors is that they rely upon purely kinetic (so-called “hit-to-kill”) or enhanced kinetic (creating a debris field) interception where the relative speed of the vehicle and the associated kinetic energy contributes significantly to the resulting damage. Anti-aircraft intercpetion, on the other hand, generally uses a relatively large explosive warhead to perform structural damage to the airframe and/or create solid debris that is ingested into the engine, damaging propulsive function.
Stranger
The Patriots were magnificent as morale boosters for the country as a whole. Their other military effect was zero with zero.
In fact, as an addendum to the morale issue (their complete failure technologically was made known only a while after the war), although generally a positive, from personal anecdote I can tell you we eventually began to worry about the one-two punch of incoming Scud (no gas) and shortly thereafter incoming Patriot (ditto, but a sizable ballistic object).
ETA: on the side note of the war’s possible “messiness,” the lack of warm fuzzies for Israel is/was not new. What was new, and spectacularly bad for Israeli morale, was restraining from undertaking warfare in defense of itself–a first time in its history, and a bad precedent.
This has been widely discussed but I don’t think there is good data about the PAC-2’s effectiveness either way. There was no high quality field data acquisition equipment – either optical or telemetry. The early optimistic numbers were based on the operator radar symbology. IOW the system itself indicates whether it thinks a successful intercept happened, which then allows the operator to focus on other targets. It doesn’t mean the intercept actually happened, only the radar and processing system thought it was close enough to flag a “success” symbol to the operator.
PAC-2 was essentially command-guided from the ground using ground radar. The only real optimization was a passive seeker in the missile which downlinked its view to the ground, called “track via missile”. It is actually hard to believe any ABM using pure radar guidance could work very well since it essentially works by merging two radar blips. That is why all new ABM systems use some kind of electro-optical or active millimeter-radar seeker in the kill vehicle.
The PAC-2’s effectiveness was analyzed using standard-definition TV footage which was very limited. However typical engagement doctrine was fire four PAC-2 missiles at each incoming ABM target, so obviously 75% could miss and still have a successful intercept. This would produce a lot of video showing misses or sacrificial self-destructs, yet if 1 of 4 actually hit the target it would be a tactical success.
The same video analysis method has been used to evaluate Israel’s Iron Dome ABM system, and some of the same analysts claim that just like PAC-2, Iron Dome is only 5% effective: http://aviationweek.com/blog/iron-dome-are-critics-target
However some of the Iron Dome videos look much better than 5% effective (main part starts at about 00:25):
Back to the OP question, the Israeli Iron Dome and David's Sling ABM systems supposedly have some anti-aircraft capability: https://en.wikipedia.org/wiki/David%27s_SlingI might add that much of my initial contact with the Patriot-Scud analysis–and final contact, since I didn’t pursue it afterwards–was through work with Postol at MIT, who was neither the first nor last reputable scientist with an extraordinary political drive.
I also should qualify, I now think, my post above when I said “technological failure.” If only all such technologies pressed rapidly into service were such failures, revealing so much about the scope and complexity of the engineering.