MX (Peacekeeper) deployment concepts.

[marauder2048]

The microsecond clock issues and time-on-target aspect wasn't that difficult to overcome for an attacker. You didn't need great
accuracy just big 25 Megaton warheads which the SS-18s could launch and microsecond accuracy clocks.

The big issue for Dense Pack is that was especially vulnerable to soft landers or earth penetrating warheads.

 

[bobbymike]

Try 40m.

That source is wrong or quoting the wrong number. I have seen a similar number in other sources, but never good ones. For instance:

https://apps.dtic.mil/dtic/tr/fulltext/u2/a451527.pdf - page 40, "...with CEP of 400 feet"
https://www.lasg.org/Modernization/Postol_Trident_2Feb1998.pdf - slide 43 "...supposed to have an overall CEP of 100 meters"
Appendix I Weapon Systemslink.springer.com › content › pdf › bbm:978-1-349-08505-7 › 1.pdf "... < 130m"

https://www.tandfonline.com/doi/abs/10.1080/09700167809421478?journalCode=rsan20

LGM-118 Peacekeeper (MX) | Missile Threat

The LGM-118 Peacekeeper (MX) was a solid-fueled intercontinental ballistic missile built by the United States designed to attack hardened military targets. Peacekeeper Development The Peacekeeper program began in 1971 as the missile experimental (MX) system as a way to increase the U.S...

missilethreat.csis.org

That, of course, assumes it worked at all. The AINS didn't exactly have a stellar record. I seem to recall parts being found in a dumpster by one of the news shows?

One USAF general back in the day described Peacekeeper's accuracy as, "absolutely eye-watering". And there isn't a program out there that doesn't have scrap.

Interesting timing as around Peacekeeper deployment I, at least, started to read more about the potential of conventionally armed ICBMs (I have a 1991 RAND study somewhere). It’s makes sense to contemplate if MX was hyper-accurate.

With modern material technology they should build super-hardened MMIII replacement silos IMHO.

 

[marauder2048]

With modern material technology they should build super-hardened MMIII replacement silos IMHO.

Super-hardened silos in the geometric shadow of some mountain would be really survivable.
Though, I gather that there's still a lot of uncertainty about super hardened silos in the nuclear weapons effects environment.

Short of the largest conventional explosion test ever deliberately undertaken by mankind, I don't think you
could resolve those uncertainties without a resumption in nuclear testing.

 

[Yellow Palace]

Short of the largest conventional explosion test ever deliberately undertaken by mankind, I don't think you
could resolve those uncertainties without a resumption in nuclear testing.

Oddly enough, that's exactly the reason (or one of them) for very large conventional tests like MINOR SCALE and MISTY PICTURE.

 

[marauder2048]

MISTY PICTURE.

Sounds like DTRA was getting test names from pr0n actresses.

 

[Archibald]

ROTFL

 

[Maury Markowitz]

One USAF general back in the day described Peacekeeper's accuracy as, "absolutely eye-watering".

110 m certainly fits that description, I see no reason to inflate its capabilities to ones that border on physically impossible.

And there isn't a program out there that doesn't have scrap.

I'm surprised anyone is attempting to apologies for Lockheed's part in the program, especially given that even the Air Force was so keen to dump them the instant they could.

In this particular case, Lockheed was found to be dumping *production examples* in the garbage. This is not a case of "waste", this is a case of basically handing your latest technology to anyone from the Soviet consulate who happens by.

And why were they doing this? Because it turns out they were faking the records, buying illegal parts, and then trashing it all. Meanwhile, the units that were actually installed in the missiles were known to not work.

A disaster end-to-end.

Super-hardened silos in the geometric shadow of some mountain would be really survivable.

Only for one particular approach path. This was the original plan for MX (when it was still Golden Arrow/AICBM) but with FOBS there is no shadow, and even with smaller missiles, as warhead weight dropped you could easily loft it above any reasonable approach angle. SLBMs, of course, render it useless.

 

[marauder2048]

110 m certainly fits that description, I see no reason to inflate its capabilities to ones that border on physically impossible.

IIRC, it was one of the first ICBMs with path-length fuzing.

Only for one particular approach path. This was the original plan for MX (when it was still Golden Arrow/AICBM) but with FOBS there is no shadow, and even with smaller missiles, as warhead weight dropped you could easily loft it above any reasonable approach angle. SLBMs, of course, render it useless.

FOBS generally had (has?) less accuracy than a conventional ballistic RV or MaRV.
SLBMs would have to be launched from southern patrol routes which, so the argument goes, would
render their host SSBNs more readily detected by ASW assets.

 

[Dilandu]

Super-hardened silos in the geometric shadow of some mountain would be really survivable.

Actually no, because USSR commissioned the orbital-capable ICBM - R-36orb (orbitalnaya) - as early as 1968. For them, the mountain shadow silos would not be much problem.

 

[Dilandu]

FOBS generally had (has?) less accuracy than a conventional ballistic RV or MaRV.

Well, R-36orb have 1100 meters CEP, with 2,3-megaton warhead in 1968. The average R-36 have CEP of about 1300 meters, and later (1975) R-36M have CEP of about 500 meters.

 

[marauder2048]

FOBS generally had (has?) less accuracy than a conventional ballistic RV or MaRV.

Well, R-36orb have 1100 meters CEP, with 2,3-megaton warhead in 1968. The average R-36 have CEP of about 1300 meters, and later (1975) R-36M have CEP of about 500 meters.

That's much less than that of contemporary RV.s.

Super-hardened silos in the geometric shadow of some mountain would be really survivable.

Actually no, because USSR commissioned the orbital-capable ICBM - R-36orb (orbitalnaya) - as early as 1968. For them, the mountain shadow silos would not be much problem.

FOBS generally had (has?) less accuracy than a conventional ballistic RV or MaRV.

Well, R-36orb have 1100 meters CEP, with 2,3-megaton warhead in 1968. The average R-36 have CEP of about 1300 meters, and later (1975) R-36M have CEP of about 500 meters.

None of these yield or accuracy combinations would combine for a Single Shot Probability of Kill (SSPK) against a 4000 psi target of > ~ 0.4,
Against a super hardened silo (say 50,000 ps) even the best yield/CEP would combine for a SSPK of less than 0.10.

So there was nothing to fear from FOBS that couldn't be addressed with improved hardening.

 

[Dilandu]

None of these yield or accuracy combinations would combine for a Single Shot Probability of Kill (SSPK) against a 4000 psi target of > ~ 0.4,
Against a super hardened silo (say 50,000 ps) even the best yield/CEP would combine for a SSPK of less than 0.10.

So there was nothing to fear from FOBS that couldn't be addressed with improved hardening.

Well, of course - but the problem was, that with improved hardening, the mountain shadow basing became redundant) Also, improved hardening was... costly. I'm not sure, was any prototype of super-hardened silo ever created?

 

[marauder2048]

None of these yield or accuracy combinations would combine for a Single Shot Probability of Kill (SSPK) against a 4000 psi target of > ~ 0.4,
Against a super hardened silo (say 50,000 ps) even the best yield/CEP would combine for a SSPK of less than 0.10.

So there was nothing to fear from FOBS that couldn't be addressed with improved hardening.

Well, of course - but the problem was, that with improved hardening, the mountain shadow basing became redundant) Also, improved hardening was... costly. I'm not sure, was any prototype of super-hardened silo ever created?

The point is: FOBS wasn't the solution for countering the the geometric shadow and hardened target problem.

Only very accurate SLBMs or ICBMs with MaRVs could quickly service that target set.

The former need to be well south of their typical patrol routes and have high accuracy
and the latter has to feature MaRVs with very accurate pull-up/pull-down and a comparatively large yield.

MX was $75 million for the missile; $180 million for the super hardened silo.
So that's $25 billion for 100 MX missiles which is a fraction of the $60 billion for 132 B-2s or (est.) $80 billion for Ohio/Trident D5.

Yes. Scale prototypes of super hardened silos were created. I don't think there was much doubt that super hardening was attainable.

The question was when could it countered with so-called "zero-CEP" RVs, soft-landers and real or
virtual (low alt. pure-fusion or high fusion fraction) earth penetrators.

The Russians being chased from the open oceans into bastions meant the only fast-time threat was
ICBMs with advanced MaRVs.

 

[Michel Van]

The point is: FOBS wasn't the solution for countering the the geometric shadow and hardened target problem.

FOBS has only the advance to attack from every direction from Orbit
But the Soviet still it face same problem with accuracy...

 

[Dilandu]

The point is: FOBS wasn't the solution for countering the the geometric shadow and hardened target problem.

No. It was a neutralizer for the first.

 

[marauder2048]

The point is: FOBS wasn't the solution for countering the the geometric shadow and hardened target problem.

No. It was a neutralizer for the first.

How? It wasn't a credible threat to contemporary silo hardness.

 

[uk 75]

Talking of R-36 envy, Hollywood had its own take on this in the film "Spies lik us"

Spies like them: How Dan Aykroyd & Chevy Chase nearly caused a war

Dan Aykroyd and Chevy Chase were almost at the center of a Cold War “incident” during the filming of Spies LIke Us. It all happened when they were in Norway, as Aykroyd explained to the Daily Telegraph: “We shot some of Spies Like Us in Norway, on the top of a mountain near Sognefjord , and we...

dangerousminds.net

The launcher used in the movie was based on a Grove all terrain crane. Perhaps Peacekeeper units could have done the same?

 

[Dilandu]

How? It wasn't a credible threat to contemporary silo hardness.

According to this, the Minuteman I/II silos were hardened up to 300 psi. 2,3 megaton of R-36orb created overpressure area of over 300 psi with the radius of about 1000 meters. Which is comparable with its CEP of 1100 meters, and rather modest improvement to R-36orb accuracy would solve the problem completely.

 

[Dilandu]

P.S. And I should point out, that R-36orb was based on the standard R-36, with added orbital stage. It was perfectly possible to put the orbital stage on the significantly more powerful R-36M, and thus solve the problem.

 

[marauder2048]

How? It wasn't a credible threat to contemporary silo hardness.

According to this, the Minuteman I/II silos were hardened up to 300 psi. 2,3 megaton of R-36orb created overpressure area of over 300 psi with the radius of about 1000 meters. Which is comparable with its CEP of 1100 meters, and rather modest improvement to R-36orb accuracy would solve the problem completely.

Even against a 300 psi silo, a 2.3 Megaton R-36 with a CEP of 1100m has a SSPK of ~ 0.4.

The SSPK formula has hardness and yield scaling with the same exponent so I look at it as:
it's always possible up to the 100,000 psi silos examined in the 80's to out-harden a
high-yield but comparatively inaccurate threat.

But accuracy increases SSPK at the square of CEP so the accurate threat is much harder to deal with.

For comparison, against a 4000 psi silo (max MM III), D5 with the 475 kt warhead and a CEP of 80m has a SSPK of ~ unity (0.998).

 

[Archibald]

This was the original plan for MX (when it was still Golden Arrow/AICBM)

Granite-mountain-basing ICBMs. Wow. The next best thing is Project Ice Worm: greenland-ice-cap-basing ICBMs.

Ah, 60's Cold War madness...

Where there ever serious plans to base ICBMs on the goddam Moon ? There are potentially immense underground cave in Oceanus Procellarum - the Marius Hills, exactly.

 

[marauder2048]

Granite-mountain-basing ICBMs. Wow. The next best thing is Project Ice Worm: greenland-ice-cap-basing ICBMs.

Ah, 60's Cold War madness...

What's mad about (granite) mountain basing? It was a notional basing mode in the GBSD RFI!

 

[sferrin]

Talking of R-36 envy, Hollywood had its own take on this in the film "Spies lik us"

Spies like them: How Dan Aykroyd & Chevy Chase nearly caused a war

Dan Aykroyd and Chevy Chase were almost at the center of a Cold War “incident” during the filming of Spies LIke Us. It all happened when they were in Norway, as Aykroyd explained to the Daily Telegraph: “We shot some of Spies Like Us in Norway, on the top of a mountain near Sognefjord , and we...

dangerousminds.net

The launcher used in the movie was based on a Grove all terrain crane. Perhaps Peacekeeper units could have done the same?

 

[Dilandu]

Even against a 300 psi silo, a 2.3 Megaton R-36 with a CEP of 1100m has a SSPK of ~ 0.4.

The SSPK formula has hardness and yield scaling with the same exponent so I look at it as:
it's always possible up to the 100,000 psi silos examined in the 80's to out-harden a
high-yield but comparatively inaccurate threat.

But accuracy increases SSPK at the square of CEP so the accurate threat is much harder to deal with.

For comparison, against a 4000 psi silo (max MM III), D5 with the 475 kt warhead and a CEP of 80m has a SSPK of ~ unity (0.998).

All that I pointed out, is that mountain shadow did not really add much to super-hardened silos as themselves.

 

[marauder2048]

Even against a 300 psi silo, a 2.3 Megaton R-36 with a CEP of 1100m has a SSPK of ~ 0.4.

The SSPK formula has hardness and yield scaling with the same exponent so I look at it as:
it's always possible up to the 100,000 psi silos examined in the 80's to out-harden a
high-yield but comparatively inaccurate threat.

But accuracy increases SSPK at the square of CEP so the accurate threat is much harder to deal with.

For comparison, against a 4000 psi silo (max MM III), D5 with the 475 kt warhead and a CEP of 80m has a SSPK of ~ unity (0.998).

All that I pointed out, is that mountain shadow did not really add much to super-hardened silos as themselves.

Silo hardening helps with the yield threat problem; mountain shadows help with the accurate threat problem.
FOBS was the former, not the latter.

But since fixed basing mode missiles have been subject to the combined threat since the late 70's...

 

[Dilandu]

Where there ever serious plans to base ICBMs on the goddam Moon ? There are potentially immense underground cave in Oceanus Procellarum - the Marius Hills, exactly.

Well, the Project Horizon military moonbase project of 1959 was hinted to be capable of being used as IPBM (Inter-Planetary Ballistic Missiles) position. The main advantages were:

* Distance, that made any sudden strike from Earth against Moon-based IPBM's impossible; the projectiles would took days to reach the Moon.
* Camouflage, that allowed missiles to be hidden in craters and crevices - so the opponent could not easily found them (contrary to, say, orbital basing, where missiles would be constantly on plain view)
* Some hardening, due to the ability to use lunar regolith to provide additional protection for missiles (again, much more practical than hauling such protection from Earth)
* Not actually made USSR nervous - since it would took days for IPBM's from Moon to reach Earth, USSR may not fear American sudden attack - so, politically it would make both sides trust each other a bit more.

Disadvantages are obvious - enormous cost of placing and maintaining the IPBM arsenal on Moon. The IPBM booster must be big enough to allow direct Moon-Earth flight. Which means, that it would be... bigger than Apollo Lunar Module, and harder to put in place. The last problem could be solved by using moon-produced fuel - like aluminum and oxygen, extracted from regolith - but it doesn't seems that there were much thoughts about that in 1950s (as far as I could say, the idea of using Lunar soil to produce aluminum based fuel was developed in USSR in 1960s).

 

[Dilandu]

Silo hardening helps with the yield threat problem; mountain shadows help with the accurate threat problem.
FOBS was the former, not the latter.

Again, it was NOT implausible or impossible to increase the accuracy of FOBS - for example, using stellar navigation, like Trident, on their de-orbiting stage - to improve accuracy to the point, when the difference between FOBS and ICBM would disappear. So the best that mountain shadow could achieve, is to force the opponent to spend more on orbital missiles. Would it be cost-effective?

 

[marauder2048]

Silo hardening helps with the yield threat problem; mountain shadows help with the accurate threat problem.
FOBS was the former, not the latter.

Again, it was NOT implausible or impossible to increase the accuracy of FOBS - for example, using stellar navigation, like Trident, on their de-orbiting stage - to improve accuracy to the point, when the difference between FOBS and ICBM would disappear. So the best that mountain shadow could achieve, is to force the opponent to spend more on orbital missiles. Would it be cost-effective?

I can't find any evidence to suggest that orbital bombardment would ever rival what you could do with sub-orbital weapons wrt accuracy.
Stellar sighting for D5 is used to resolve INS mis-orientation due to strategic navigator errors i.e. initial state errors.

 

[Dilandu]

I can't find any evidence to suggest that orbital bombardment would ever rival what you could do with sub-orbital weapons wrt accuracy.

I see the only one reason why it MAY not be possible to do - more flat re-entry trajectory of FOBS warheads, which increase the influence of atmospheric disturbances. Because frankly, there is no practical reason why upper stage, having a lot of time to correctly calculate its position and enough delta-V to make every micro-correction required to be even more precise than ICBM.

 

[marauder2048]

I can't find any evidence to suggest that orbital bombardment would ever rival what you could do with sub-orbital weapons wrt accuracy.

I see the only one reason why it MAY not be possible to do - more flat re-entry trajectory of FOBS warheads, which increase the influence of atmospheric disturbances. Because frankly, there is no practical reason why upper stage, having a lot of time to correctly calculate its position and enough delta-V to make every micro-correction required to be even more precise than ICBM.

A true orbit over the south pole (the only reason to have FOBS) is what nearly 2 hours? Winds over target, rain over target, all sorts of things can change in that time.
In addition to the basic observation that guidance errors accumulate over time.

Say FOBS achieved Trident D5 like accuracies: It's a not a fast-time threat to ICBMs and even Safeguard had no trouble knocking down FOBS.
And because FOBS is a huge payload, the defense is not faced with the saturation threat a la MiRV.

So FOBS quickly lost it sneak attack capability, its accuracy was challenged and it was vulnerable to ABM treaty compliant defenses.
You can see why it was retired.

 

[Dilandu]

A true orbit over the south pole (the only reason to have FOBS) is what nearly 2 hours? Winds over target, rain over target, all sorts of things can change in that time.
In addition to the basic observation that guidance errors accumulate over time.

Er, low-altitude orbit is about 90 minutes.

 

[marauder2048]

A true orbit over the south pole (the only reason to have FOBS) is what nearly 2 hours? Winds over target, rain over target, all sorts of things can change in that time.
In addition to the basic observation that guidance errors accumulate over time.

Er, low-altitude orbit is about 90 minutes.

Which doesn't substantially alter my point. That's still 4.5x the typical ICBM time of flight.
Even the most "hair trigger" anti-ICBM alarmists aren't worried about 90 minutes of decision time.

 

[Dilandu]

Which doesn't substantially alter my point. That's still 4.5x the typical ICBM time of flight.
Even the most "hair trigger" anti-ICBM alarmists aren't worried about 90 minutes of decision time.

Yeah, one problem) They are MUCH harder to detect) Firstly because the majority of early warning radars of US during cold war were not pointed into Southern direction) Secondly, because the trajectory of orbital missile is MUCH lower than the ballistic trajectory of ICBM. The ICBM climb as high as 2000 km. The FOBS - 150-200 at most. So, the curvature of the Earth efficiently hide the incoming orbital bombs from the radars that MIGHT be looking in their direction.

Essentially, only Defense Support Program satellites have realistic chances to notice attack. But problem was, that launches into the southern direction are not what it anticipated. So when no missiles would appear on BMEWS radars (because of low trajectory), the situation would became very confusing.

 

[marauder2048]

Which doesn't substantially alter my point. That's still 4.5x the typical ICBM time of flight.
Even the most "hair trigger" anti-ICBM alarmists aren't worried about 90 minutes of decision time.

Yeah, one problem) They are MUCH harder to detect) Firstly because the majority of early warning radars of US during cold war were not pointed into Southern direction) Secondly, because the trajectory of orbital missile is MUCH lower than the ballistic trajectory of ICBM. The ICBM climb as high as 2000 km. The FOBS - 150-200 at most. So, the curvature of the Earth efficiently hide the incoming orbital bombs from the radars that MIGHT be looking in their direction.

Essentially, only Defense Support Program satellites have realistic chances to notice attack. But problem was, that launches into the southern direction are not what it anticipated. So when no missiles would appear on BMEWS radars (because of low trajectory), the situation would became very confusing.

The US built the early warning infrastructure that could detect FOBS launches and track FOBS because it had to do so anyway for Soviet SSBNs
and to satisfy dual phenomenology requirements for launch under attack/warning.

The BMD system the US built was based on multi-faced phased arrays and two interceptors that could handle FOBS...

Meaning that, FOBS was a short-lived, expensive failure.

 

[Dilandu]

The US built the early warning infrastructure that could detect FOBS launches and track FOBS because it had to do so anyway for Soviet SSBNs
and to satisfy dual phenomenology requirements for launch under attack/warning.

Most of this system was based on radar detection of incoming warheads, and was not exactly very reliable against flat-trajectory missiles.

The BMD system the US built was based on multi-faced phased arrays and two interceptors that could handle FOBS...

Probably, because penetration aids of R-36orb were as good as of R-36. And considering how MUCH more the Safeguard/Sentinel system would cost to deploy... As you said, it -

was a short-lived, expensive failure.

P.S. The R-36orb wasn't actually expensive) It was just the new upper stage to the usual R-36 missile) Considering how many nerves its mere existence burned in Pentagon, it paid itself off several times)

 

[marauder2048]

The US built the early warning infrastructure that could detect FOBS launches and track FOBS because it had to do so anyway for Soviet SSBNs
and to satisfy dual phenomenology requirements for launch under attack/warning.

Most of this system was based on radar detection of incoming warheads, and was not exactly very reliable against flat-trajectory missiles.

The BMD system the US built was based on multi-faced phased arrays and two interceptors that could handle FOBS...

Probably, because penetration aids of R-36orb were as good as of R-36. And considering how MUCH more the Safeguard/Sentinel system would cost to deploy... As you said, it -

was a short-lived, expensive failure.

P.S. The R-36orb wasn't actually expensive) It was just the new upper stage to the usual R-36 missile) Considering how many nerves its mere existence burned in Pentagon, it paid itself off several times)

I can find no compelling evidence whatsoever that FOBS altered US force structure, procurement or doctrine; what the US built
that could detect, track and intercept FOBS is what it would have built anyway to handle the Soviet ICBM and SSBN threat
and satisfy a LUA/LOW posture.

The US was going to deploy Safeguard/Sentinel anyway; FOBS would have been an easy target since pen aids would not have been
able to credibly mask an RV of the R-36orb type and the "threat cloud" was small enough to be subsumed by a single Spartan detonation.

If FOBS had stayed around, then Safeguard/Sentinel would probably have stayed since FOBS greatly relaxes the time pressures for
securing a defensive nuclear weapons release authorization; that's what all of the US nuke-tipped ABM programs really fell-down on.

 

[Dilandu]

If FOBS had stayed around, then Safeguard/Sentinel would probably have stayed since FOBS greatly relaxes the time pressures for

And it would cost USA orders of magnitude more, than for USSR to just put new orbital upper stage on old R-36M (which were alredy slated to be replaced by new R-36M). So, clearly cost-effective, if it would provoke US into building cistly ABM's to protect missile bases.

 

[marauder2048]

If FOBS had stayed around, then Safeguard/Sentinel would probably have stayed since FOBS greatly relaxes the time pressures for

And it would cost USA orders of magnitude more, than for USSR to just put new orbital upper stage on old R-36M (which were alredy slated to be replaced by new R-36M). So, clearly cost-effective, if it would provoke US into building cistly ABM's to protect missile bases.

The US just would have reactivated the ABM installations it had already built and was already going to build FOBS or no FOBS.
Not a big deal.

That was obvious to even the most myopically pedantic Russian which I'm sure played a part in why FOBS was abandoned.

 

[Dilandu]

The US just would have reactivated the ABM installations it had already built and was already going to build FOBS or no FOBS.
Not a big deal.

Installation. There was only one complete, able to cover just one base. And it cost a fortune to run, while FOBS missile cost as much as usual ICBM.

That was obvious to even the most myopically pedantic Russian which I'm sure played a part in why FOBS was abandoned.

I would really appreciate if you restrain yourself for making such provocative comments on a brink on personal attack.

FOBS stayed in service from 1968 till 1983. It wasn't expensive to maintain. It was decommissioned specifically because USA insisted on forbidding FOBS-type missiles in 1979 strategic weapons reduction treaty. That's how "it wasn't a big dealt", yeah. US administration obviously thought it was, since forbidding such systems was their initiative.

 

[marauder2048]

Installation. There was only one complete, able to cover just one base. And it cost a fortune to run, while FOBS missile cost as much as usual ICBM.

That's fine. How many FOBS RVs were there? 18? I like those odds.

And of course, we've established that the FOBS the Russians had through this period was not a credible threat against
Minuteman I through Minuteman III silos.

There's no evidence ABM cost a fortune to run; radar manning isn't all that expensive.
And SRM ensiloed/encanistered missiles are about the cheapest weapons system wrt O&S.

The US would have run it had the threat been there. It would have had utility against other RVs as well.

FOBS stayed in service from 1968 till 1983. It wasn't expensive to maintain. It was decommissioned specifically because USA insisted on forbidding FOBS-type missiles in 1979 strategic weapons reduction treaty. That's how "it wasn't a big dealt", yeah. US administration obviously thought it was, since forbidding such systems was their initiative.

It was expensive to develop and test and hypergolic-fueled big ICBMs aren't exactly noted for being wooden rounds.

And the Russians quickly agreed to the terms because their expensive investment had no utility.

It's no different from the fact that the Russians agreed to ABM because the initial Moscow System had hit
major development problems and was looking non-credible against what the US could toss at it in the near-term.