Source Docs at My Site Now
USAF Ballistic Missiles [Programs] 1958-1959
USAF Ballistic Missile Programs 1962-1964
USAF Ballistic Missile Programs 1964-1966
USAF Ballistic Missile Programs 1967-1968
USAF Ballistic Missile Programs 1969-1970
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So anyway; you know the whole concept of "pindown"; where you blind an ABM site by continously detonating nukes over it?
Turns out it's
far more applicable to ICBM launch sites than to ABM sites.
The '67-68 document has some interesting information:
To counter the threat posed to inflight missiles by radiation, the Air Force had directed installation of zircalloy shielding to prevent hot X-rays from penetrating the LGM-30F's guidance and control mechanism and burning out its electronic components. By the summer of 1966, however, tests showed that tantalum shielding offered the "best compromise for effectiveness and weight. " Air Force officials estimated 170,000 pounds of tantalum sheet, roughly 0.025 inches thick, would be required to protect the guidance and control units of all F missiles, replacing zircalloy where necessary.31
Besides providing protection for the guidance and control package from X-rays, the Air Force approved the installation of radiation shielding elsewhere in the missile. Certain nozzle components, for example, were vulnerable to X-rays. Also, the angular accelerometer and related electronic guidance circuitry had to be kept secure from neutron bombardment.32
The second nuclear phenomenon that menaced missiles in flight was electromagnetic pulse. Tests conducted during summer and fall of 1966 disclosed that safeguards previously installed against this nuclear effect were inadequate. In the LGM-30F, for example, existing grounding and shielding did not protect antennas and inductive loops that were especially vulnerable to electrical overload. Modifications to provide additional protection were undertaken, while experiments continued to verify the adequacy of the changes and to determine if other alterations were needed.33
The effect of nuclear detonations on missiles during powered flight opened the way for a new tactic. As has been indicated, an attacker, by detonating warheads some 300,000 feet above the silo that protected the Minuteman force, could create a radiation barrier--X-rays, gamma rays, and neutrons—through which U. S. missiles could not safely pass. This tactic was called "pindown" because it would force SAC to delay launching the retaliatory force until after the radiation had dispersed.
It's taken a bit further in the '69-70 document:
The Air Force pursued other projects to complement its missile hardness modifications. One, a high altitude radiation detection system (HARDS), sensed and reported a nuclear-charged environment. In January 1968 HARDS had been installed in five airborne launch control center aircraft and at one launch control facility in each Minuteman wing. By the end. of 1968 all post attack command control system (PACCS) aircraft carried HARDS. Furthermore, in October 1968 OSD expanded the ground-based network--the electromagnetic pulse sensor system (EMPSS)--to 20 Minuteman and six Titan II launch control centers; installation was completed in early 1970. OSD also approved incorporation of cancel launch in process (CLIP) devices in all Minuteman II and Modernized Minuteman control centers.
[CLIP enabled launch crews to override a valid firing order once pindown was detected.]
So...how is this a threat?
Well, you know how you can't launch a ballistic missile until you are
absolutely sure that NUDETS are going to be occuring on US soil, etc, because it can't be recalled or blown up in flight?
This means that if say, the Soviet Union decided on a first strike aimed at our bomber airfields and missile fields; while the bombers could disperse on warning of the missiles in the air -- our missiles would largely be caught in their silos.
Now; we would probably begin to issue definite salvo fire orders to our ICBM Wings several minutes before the first RV impacts on CONUS -- because by that point we would have multiple confirmations of enemy attack from multiple sources (OTH radar, satellites looking over soviet ICBM fields; radar confirmation from the big radars we have) and you would begin to see the first streaks of re-entry about 30-40 seconds before initation.
The thing is; the big Soviet Missile fields would have nearly an hour to launch their missiles at us (30 minutes to begin firing our own missiles; then a 35~ minute flight time to Soviet Russia); before targets in Russia begin to feel the wrath of US retaliation.
Now, you're asking me -- What about forward deployed missiles and fighter bombers in Europe/Japan/Etc?
It goes to that point earlier -- once you've ignited the blue touch paper and launched a nuclear weapon; there's no going back.
So our tactical forces would be dispersing into airborne alert, moving away from bases, and on carriers, the nuclear weapons would be in the process of being assembled in the special weapons magazines. But they can't nuke away until we're absolutely sure that CONUS is about to be hit with many many nuclear weapons.
So this means that we probably get at least a wing or two (150 to 300 Minutemen) off the ground before the nukes hit and scattered launches from the other Wings including maybe a couple Titan IIs.
In fact; it's almost likely to be Wing I and Wing II which fire mostly -- because as built, they only had enough supplies to last six hours on alert once cut off from commercial power; and the emergency generators on the silos were soft.
Yes, you heard me right. The missile silos on the first 300 Minuteman launchers we built were rated at 300 PSI, and the command centers 1,000 PSI; but the emergency generators for the launch control center and launchers weren't even hardened at all, and they only had enough diesel to last for six hours!!!
We eventually did do a modernization program for those two wings to bring them somewhat up to the standards of the other wings; but that was late-ish in the program; and those wings can never really be trusted to be as damage resistant as the newer ones. So those missiles fly first, because in any case they are going to be destroyed/rendered inoperable by virtually any attack.
It's also because of this that the majority of SAC HQ/Higher Command attention is going to be focused on those two wings to get their missiles off.
Why? Because SAC launch crews aren't automations -- a significant fraction are going to need convincing from higher ups that this is for real, yes, it's for real -- launch your missile!
It may ultimately take an override command from higher up HQs or the ALCCs to launch the missile - and that wastes time.
The remainder of the Minuteman Force -- Wings III, IV, V, and VI, have emergency facilities hardened to varying degrees (25 to 1,000 PSI), but all have enough diesel to last nine weeks on alert once cut off from commercial power; so there isn't as much pressure to use them.
So we've gotten off a couple hundred missiles before impact -- but the remainder of our force -- the other 700 to 850 Minutemen and 50~ Titan II are caught sitting on the ground and have to ride out the attack.
For the purposes of this calculation; we'll assume that we're attacking minuteman silos with 500 kiloton warheads with a CEP of 1,000m (0.53nm) We also won't consider warhead reliability, missile reliability; or the effect of bias on CEP.
Rough SWAGs for damage radiuses give 315m (0.17nm) for 300 PSI -- remember that while the launch control center of the latest Minutemen are hardened to 1,000 PSI -- the silo itself and the diesel generator complex are not as well hardened.
SSPKs with such a weapon would be about 6.9% -- and if we wanted a kill probability of about 50% on that silo (remember; we just need to damage it enough so it can't launch) it would take about seven warheads. Since each Wing has 150 launchers, that's a thousand groundbursts occuring over an area about 10,000 square miles -- the size of roughly Massachusetts....
at minimum.
That's a lot of hard radiation and fallout that's going to be blanketing the launch fields -- and since the Soviet RVs will be arriving over a fairly longish period (for nuclear war) to avoid fratricide; it's entirely possible that our surviving missiles will be held down by a prolonged nuclear barriage that lasts for an hour or more; plus whatever time it takes for the radioactive clouds from the groundbursts nearby to dissipate enough to make launches feasible.
By the time we can once again launch reliably, the Soviets could have reduced our ICBM force to a level where it can't counterforce what Soviet silos are left unfired or counterindustry Soviet cities enough to attain Assured Destruction.
When you combine this with the increasing soviet air defense forces and the increasing age of our bomber fleet; it seems that really, the Soviets had checkmated virtually all of our triad except the SSBN force.
And even the survival/effectiveness of our SSBN force is a bit questionable.
Why?
Due to the range of Poiseidon (2,500 nm); our boats have to stay in the North Atlantic about 600-700 nautical miles west of Ireland in order to hit Western Russia; and for our Pacific Poiseidon/Polaris boats, they can pretty much blow away Siberia; but that's it.
If you wanted to hit the Urals region of Central Russia; then your SSBNs would have to brave the G-I-UK Gap or the Okhotsk Sea; and that's a fairly dangerous thing in an era where Soviet ASW forces, both Surface and Subsurface are substantially improving, making life very dangerous for SSBNs.
Why? To give you an example; the Soviet YANKEE SSBN has sixteen missile tubes; and they are fired in four salvos of four missiles.
To prepare for launch takes eight minutes; and a full salvo of four missiles takes 32 seconds. Then you have to spend three minutes after each salvo correcting your depth. After the second salvo; it seems that you then have to spend about a half an hour correcting your trim; because you've fired off a hundred plus tons of missiles; and taken on at least that much amount of water as the missile tubes fill post-launch.
Oh; did I mention the fact that firing an SLBM is very noisy? First you have the hatches opening, KA WUNK KA WUNK; then the huge gas bubble and noise from each launch.
Ideal conditions for a enemy SSN to detect you and then drop a SS-N-15 or SUBROC on your launch point. They won't be able to stop your first salvo; but they can prevent you from firing your full complement.