Help me understand why BMD is so hard, assuming you’ve already built hypersonic missiles, which apparently the Russians have done. I’m not arguing it wouldn’t be expensive, but it seems like a solvable problem, assuming you have the technical resources to build it.
If it takes 20 minutes for inbound missiles to reach you that gives you time to use your satellites to determine the trajectory of the missile before it leaves space and heads back to earth. What’s the really hard part here?
Pretty much everything.
BMD ends up with Reagan’s SDI aka Star Wars. Just the software is hopeless. Back in the 80’s Dave Parnas took it on himself to point out to everyone just how bad it was. (He even visited my department on the other side of the planet giving his talk.)
Nothing has changed here. Even point 6, whilst written in the mid-80’s remains true. Any idea that we have the capability to actually get even a modern take on SDI working is very naive.
I presume Russia faces the exact same issues we face, which I guess is the only good news.
@Francis_Vaughan has address the incredibly complexity and reliability of the software (and implicitly, the command, control, & integration aspects of such a system) but there are also hardware and physical limitations. Although earlier systems like Safeguard used nuclear armed interceptors these proved politically infeasible as well as likely doing as much damage as the incoming weapon (and therefore only useful for assuring retaliatory capability, not in providing the ‘protective shield’ that Reagan et al promoted), modern interceptors use kinetic ‘hit to kill’ interceptors that require extremely precise targeting. The physical act of interception has been demonstrated with a degree of reliability but the problem is that in order to perform this there needs to be a sensor (‘seeker’) on the interceptor. This is an infrared sensor because this band of radiation that stands out distinctly against the space background but that means that the seeker has to be cooled or else the sensor gives false images which is something the EKV has had a lot of problems with (in addition to being fooled by direct or reflected sunlight).
@Francis_Vaughan’s link also mentioned decoys as a problem of software discrimination but it is even worse than that; it is possible to make decoys that are light and easy to deploy but are literally indistinguishable in IR and radar cross section from the actual reentry vehicle. This makes spoofing an interceptor with multiple decoys almost trivial, as if the kill vehicle didn’t have enough problems just trying to discriminate the target from natural phenomena. And the issue of response time to a real threat means that human-in-the-loop just isn’t feasible; this has to be an automated system. How many complex, fully autonomous systems dealing with critical defense applications do you trust?
There is also a more fundamental problem with strategic ballistic missile defense in general that, while not applicable to GMD because it isn’t really ‘strategic’ in the true sense of the term, is applicable to any hypothetical defensive shield; that is, that missile defense is inherently destabilizing. If you have a system that you truly believe to be invulnerable against an opponent, the deterrent effect of their arsenal is therefore lessened and you have an incentive to strike them before they improve their penetration capabilities against your system. Conversely, if an opponent believes that you are implementing an impenetrable shield, they are highly motivated to strike before it is active and they lose the ability to retaliate against a disarming first strike. Of course, invulnerable missile shields are purely a hypothetical that don’t exist in the real world, and deterrence theory is more faith than fact, but the reality is that preventing an opponent from destroying you with their arsenal of hundreds of ICBMs carrying thousands of RVs is predicated on preventing them from ever issuing a launch order because even if just a small fraction of those weapons make it through your defenses you are still going to have a really terrible next century.
So, in answer to the question, “What’s the really hard part here?”: it’s all hard, every part of it, and even if it worked well it would not be adequate to protect against a concerted strategic attack. We struggle to field a system that demonstrates enough reliability even in orchestrated tests to be considered adequate against a single threat.
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@Stranger_On_A_Train @LSLGuy how do you think THAAD would do against an attack like this one from Iran in 2020, when something like one or two dozen missiles were fired en salvo. (THAAD either wasn’t used since it wasn’t deployed or the US had been warned before so they didn’t bother, sources differ).
My own observations have been.
THAAD, PAC-3 and Russian and Chinese systems like the S-400 and HQ-9B seem to have been designed to tackle something like Iraqi Scud attacks in 1991, which were very limited compared to the modern era. About 40 or so missiles launched in three weeks. Iran and others will launch multiple salvo’s of dozens each, and unlike the 1991 Scuds, will have at least some penetration aids, which seems tp be a completely different problem (at least to my layman eyes).
(Plus the PAC hasn’t been much ore than OK versus Iraqi in 2003 and Houthi missiles later, engagements which are much more like 1991 than the modern day).
As far as I could tell, the Ukraine war has confirmed that non-nuclear BM with a range longer than a few hundred KM are just extremely expensive one shot Artillery pieces. You only really want to use them if you don’t think your Air Force is of any use (which admittedly is true for Iran and was the case with China vis-via the US until a decade or so ago.)
Anything I have to say is speculation.
I had not read of the details of that attack before your wiki cite today. And what details we have are of course fuzzy with both sides claiming different details. The overall rate of missile launch was about 1 per minute according to the Iranians, and more like 1 every 5 minutes according to the Americans.
In any case, that relatively low incoming rate would certainly improve the ability of any defense to handle the C3 and targeting problems. Had all 15-ish missiles arrived within just a minute or 3 the defense would have faced a VERY different and much more difficult problem. Given the low rate, the limiting factor on any defense would have been magazine size and/or how quickly they can reload the launchers from their matching reload trucks.
So Iranian tactics, for whatever reason, were a gigantic gift to the defense, had there been any. If the Iranians knew the US had no effective ABM defense, then the slow pace could easily have been deliberate so as to keep the first responders’ heads down for an extended period while the fires and injuries from the initial warheads would have worked unabated. Certainly military buildings & people are better at self-managed aid and DIY damage/fire control than are civilian cities. But at the same time, bases also have fire brigades, ambulances, and clinics / hospitals for a reason - the damage and casualty control advantages they confer. By dribbling ordnance on target over a span of hours, the Iranians may have slowed those more powerful damage limitation responses.
Here I’m on real weak ground. Other than the long public litany of failed tests, there’s almost no unclassified info on the as-deployed THAAD. Is it reliable or broken a lot? Are the crews skilled or mostly stumblebums? Does the employment doctrine really match the threat profile? How hair-trigger ready are they really on a random Wednesday at 1am? etc.
Those are the hard questions much more than “Is the published intercept altitudes, speeds, and target detection / discrimination greater than the specs of the adversary weapons?”
The good news is a full-up loaded THAAD battery has 48 missiles on the rails and a bunch more on trucks. So if THAAD had been there that day magazine depth and reload time would not have been a factor even had all 20-ish inbound missiles arrived simultaneously.
Is it possible to interfere effectively with the electronics on missiles after they are launched? In a “we are about to get destroyed” scenario, can an electromagnetic pulse (EMP) be set off that would cause launched missiles to fail (i.e., fall but not detonate or detonate somewhere besides their target)?
In a word, no.
Any well designed system is going to be robust against EMP or other interference; the LGM-30G ‘Minuteman III’ and LGM-118A ‘Peacekeeper’ are actually designed to fly out through a nuclear near-miss detonation to minimize the likelihood of a disarming first strike. Once the booster phase is over, the interceptor is well above the mesosphere and the region where high altitude electromagnetic pulses (HEMP) occur. In theory a directed energy weapon (laser or proton beam) could weaken the structure of the booster or ‘blind’ the post-boost vehicle astrogation sensors (for those that use stellar sighting—most just use purely inertial guidance) but the reality is that development of those weapons at strategic ranges is even less mature than kinetic interception. In the reentry phase, the RV is a purely ballistic object, or for a maneuvering reentry vehicle (MaRV) using internal mass redistribution and wave-gliding to alter its course without any kind of interaction and good luck getting even a powerful EMP to penetrate the dense sheath of ionized and compressed atmospheric gas around it, notwithstanding that the weapon arming and firing electronics are extremely robust and not subject to external interference.
Stranger
Plus, even aside from “hardening”, nukes aren’t particularly dependent on sensitive electronics to begin with. Oh, there are probably systems with electronics in them, but there would be backup systems that do the job nearly as well without them (for instance, IIRC most nukes have three independent “triggers” of different sorts).
That isn’t really true. There are numerous different “links” in the arming and firing chain (divided into “strong” and “weak” links, the former providing affirmative commanded FIRE/SAFE condition and the latter assuring that there are no environments or conditions that exist in which the weapon should not fire) but the system is designed so all of the links have to be intact for the weapon to successfully work under the thesis that you’d rather have a weapon fail to fire (or at least fizzle) than have one unintentionally detonate. There is only one successful firing chain.
The ‘physics package’ in the RV (or bomb for an plane-dropped device) is very robust and well-protected against external interference because of both the conditions it has to operate in and to assure that it cannot be readily disabled by any external condition or weapon, but aside from standard redundancies in firing squibs there are not independent “triggers”.
Some information on nuclear weapon safety systems from Sandia National Labs:
Stranger
I’m surprised so much information–like that you’ve shared–is public. I’m assuming you’ve not stolen this information :). I would think it would be hard for other nations to gather all these details or confirm them. No?
You might be surprised what you can find online:
http://nuclearweaponarchive.org/
Stranger
I’m not talking about the links in the firing chain; I’m talking about the triggers. IIRC, there’s a time trigger, an altitude trigger, and an impact trigger. The first two are both set to detonate the bomb when it’s at optimal height (you generally get more destruction out of an air burst than a ground burst), so if one fails, the other will still set it off. If both of those fail, then the impact trigger should still set it off when it hits the ground (for a less-effective ground burst, but that’s a lot more than nothing).
Without going deep into technical details, this is not correct. In terms of nuclear weapon design, the ‘trigger’ is the actual mechanism that starts the fission chain reaction; for a gun-type weapon that is the slug that is propelled through the core; for a boosted fission or thermonuclear fusion device it is the linear implosion ‘pit’ that is compressed by conventional explosives to forma a ‘critical mass’. What you are referring to is the ARM/FIRE device (AFD) that receives commands to enable (ARM) the weapon, removing the physical and electrical barriers from the initiation chain, and the initiation signal (FIRE) that sends the electrical impulse to the detonators that start the implosion event which results in nuclear detonation. Depending on the type of weapon and how it is use there may be multiple conditions that have to be satisfied with some combination of AND/OR logic but the actual initiation chain is common regardless of the conditions. This AFD is quite resilient and reliable, and there are redundant AFDs just in case some unlikely defect causes one to malfunction but there are not independent ‘triggers’ either in the initiation chain or the initial fission reaction.
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