LGM-35A Sentinel - Ground-Based Strategic Deterrent (GBSD) program

On a likely related note, from today's Times:
Row over China-bound ship with nuclear cargo

Sri Lanka A ship found to be carrying uranium hexaflouride —
which can be enriched for use in nuclear weapons or power stations
— was ordered to leave Sri Lankan waters. The BBC Naples, registered
in Antigua, had arrived at Hambantota, a port on the south coast which
is run by China on a 99-year lease, from Rotterdam. It was bound for a
destination in China. (AFP)
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One air force general noted astutely that if the US removes ICBMs from inventory, a percentage of the bomber force will have to be put on permanent nuclear alert again, which would probably require a significantly larger force of aircraft than currently planned as well as increased maintenance and readiness costs associated with that.
 
sferrin said:
bobbymike said:
www.defensenews.com

Lawmakers, defense officials joust over next-gen ICBM plans

The war over a next-gen ICBM flared up at the U.S. Capitol on Wednesday.
www.defensenews.com www.defensenews.com
In the lead up to the Biden administration’s far-reaching nuclear posture review, left-leaning lawmakers say the Pentagon’s $1.2 trillion nuclear modernization plans are a money pit and question whether the United States could deter its rivals for less with only its bombers and submarines. Conservative lawmakers worried GBSD needs protection from cancellation are opposing further analysis by the Pentagon
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Why would a defense publication either intentionally, ignorantly or deceptively use the “$1.2 trillion modernization plan”? Firstly they always fail to mention that this cost is over the next 30 years and that the modernizing the Triad portion is around $350 billion the rest is maintaining the existing Triad as it is being modernized.
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"This is why we don't need ICBMS"
"Why is why we need ICBMS"

It's great :)
 
sferrin said:
In_A_Dream said:
"This is why we don't need ICBMS"
"Why is why we need ICBMS"

It's great :)
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The fact that it's even a question (in some circles) at this point is mind-boggling.
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I agree, it's kept us safe for this long. Why peel away that layer of protection while a much more technologically/economically competitive authoritarian opponent is rapidly modernizing their military.
 
Lets try and stay away from politics on this topic as much as possible. That means at the least restricting speculation on and anger about things that haven't happened yet.
 
If it’s hot fired, it probably has to roughly retain the diameter of the MMIII, though perhaps the upper stages wouldn’t taper. If it’s cold launched it could be as large as MX.
 
Josh_TN said:
If it’s hot fired, it probably has to roughly retain the diameter of the MMIII, though perhaps the upper stages wouldn’t taper. If it’s cold launched it could be as large as MX.
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Hoping for MX but reality says MMIII. Well really hoping for the “silo stuffer” proposal which if I recall was 90’ and 120” diameter :oops:
 
"The chairman of the House Armed Services Committee will not try to eliminate the controversial nuclear missile program"

Wow. That it even needs to be said is shocking. China and Russia must be laughing their a$$es off.
 
Minuteman and the entire concept of Silo based missiles is rapidly becoming obsolete. It made sense in the 1960s to protect against inaccurate RVs, but since the 1980s with increasingly accurate RVs and MaRVs, only institutional inertia is keeping them around.

A more "realistic" deployment would be to make GBSD as a road mobile/air mobile/ whatever mobile missile; and jointly deploy them as a split silo/mobile force -- i.e. 150 in Silos as a "protected" force (maybe with mini-SPRINT missiles to defend the Silos against super accurate RVs instead of trying to ultra-harden the silos) and the rest in mobile launchers similar to TOPOL-M.
 
Another point is -- Minuteman is the size it is (36,000~ kg) due to the technology at the time (1960s) and the need to carry either many RVs, or one single really big multimegaton warhead.

Midgetman has the same (or more range) and is only 13,600~ kg; in addition to being much smaller and easier to handle.

If we're not going to seriously deploy MIRVed missiles, why do we need to accept the weight/cost size limitations involved with MIRVed missiles?
 
RyanCrierie said:
Another point is -- Minuteman is the size it is (36,000~ kg) due to the technology at the time (1960s) and the need to carry either many RVs, or one single really big multimegaton warhead.

Midgetman has the same (or more range) and is only 13,600~ kg; in addition to being much smaller and easier to handle.

If we're not going to seriously deploy MIRVed missiles, why do we need to accept the weight/cost size limitations involved with MIRVed missiles?
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Future flexibility. MM3 is deMIRVd largely because of New START, but in addition to allowing for future MIRVs, the new ICBM should also allow for other potential payloads like hypersonic gliders or even pop up satellite launches to provide rapid attrition replacements. A system with significant diameter and throw weight offers a lot of future flexibility.
 
RyanCrierie said:
Another point is -- Minuteman is the size it is (36,000~ kg) due to the technology at the time (1960s) and the need to carry either many RVs, or one single really big multimegaton warhead.

Midgetman has the same (or more range) and is only 13,600~ kg; in addition to being much smaller and easier to handle.

If we're not going to seriously deploy MIRVed missiles, why do we need to accept the weight/cost size limitations involved with MIRVed missiles?
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Flexibility. You can always put a single/small warhead on a large missile then upload if you need to down the road. Can't do that with a missile optimized for a single, small traditional warhead. There's a reason both Russia and China are producing (or close to) large ICBMs capable of carrying 10+ MIRVs.
 
I think a lot of members on this forum would support a silo/mobile split BUT if anyone thinks in today’s America “a mobile nuke train or vehicle of DEATH” could be deployed is kidding themselves
 
It's funny that some mention siloed ICBMs as an obsolete strategic deterrent but forget how many ICBMs our adversaries (China & Russia) are forced to dedicate in order to target each silo.

Please read that again if it doesn't make sense.
 
Also the PRC is building new silos.

I think silo basing solves a lot of security problems while at the same time complicating targeting for competitors. The US has 450 MM3 positions; that’s a lot of nukes if you’re double tapping.

Edit to add: also silos are super low maintenance. For the most part, fifty missiles require five two man teams. Compared to an SSBN it is fantastically cheap. Mobile missiles drastically increase the manpower and equipment footprint, even if you have the controlled federal space to operate missile convoys.
 
Josh_TN said:
One air force general noted astutely that if the US removes ICBMs from inventory, a percentage of the bomber force will have to be put on permanent nuclear alert again, which would probably require a significantly larger force of aircraft than currently planned as well as increased maintenance and readiness costs associated with that.
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I'd like to correct the USAF general's statement.

If the USAF wants to retain the slice of the budgetary pie it has now in regards to nuclear forces if it retires the ICBM force, it will have to put most of the bomber force back on nuclear alert, in order to keep X number of nuclear warheads under USAF control, lest that money go somewhere else, like two more Columbia-class SSBNs.
 
In_A_Dream said:
It's funny that some mention siloed ICBMs as an obsolete strategic deterrent but forget how many ICBMs our adversaries (China & Russia) are forced to dedicate in order to target each silo.
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Going back in time 50+ years to the start of the ICBM force, the following data shakes out:

Per Glasstone 1977:
"Aircraft are damaged by blast effects at levels of peak overpressure as low as 1 to 2 pounds per square inch. Complete destruction or damage beyond economical repair may be expected at peak overpressures of 4 to 10 pounds per square inch."

So it seems reasonable to assume 3 PSI will mangle ballistic missiles in the open "on the pad".

Some of the data on Minuteman is from USAF Ballistic Missile Programs 1964-1966:

Thor Open Launch Site: 3 PSI

Atlas E Coffin = 25 PSI

Atlas F Silo = 100 PSI

Minuteman LCF: 300 PSI

Minuteman LCC: 1000 PSI

Minuteman LCC Emergency Generator (soft/300/1000)
Wing I to II were soft, Wing III to V were 300 PSI and Wing VI was 1000 PSI

Minuteman LCF Emergency Generator (soft/25/300)
Wing I to II were soft, Wing III to V were 25 PSI and Wing VI was 300 PSI

LINKY

At Wing I and II, the support equipment, air conditioning and the emergency power generator, was housed in the above ground structures of the Launch Control Facility, and Launch Support Building at the Launch Facility. In the event of an enemy attack, if the commercial power was disrupted and the emergency power generators were damaged, the LCC and LF only had approximately 6 hours to operate based on back up batteries built into the system.

Starting with Wing III, each subsequent missile wing was built by burying the Launch Control Equipment Room, LCER, (also referred to as the LCSB, Launch Control Support Building) underground alongside the Launch Control Center.

At Wing VI, as well as the final squadron that was built, the "Odd Squad" (the 564th SMS) at Malmstrom AFB, the Air Force took more extensive steps in ensuring that the Launch Support Building at the Launch Facilities were nuclear hardened by burying the LSB approximately 35 or more feet underground, adjacent to the Launch Facility.

The key thing to note is that while Minuteman missile silos may be hardened to 2,000 PSI, their ancillary supporting structures (LCFs and the Generators to run LCFs) aren't hardened as well -- it does no good if you have all the silos in a Wing linked together to fire from a single LCF if the lone surviving LCF's battery ran dead hours ago, since it's "soft" generator was destroyed in the opening strike, leaving it unable to transmit the wing launch order.

"Superhard" Silos

From a skim of concepts over the decades; superhard concepts have covered a wide range of values:

I've seen suggestions that it might be possible to mass produce silos for 1000 atm (14,695 PSI) -- or at least "mass production" compared to what it would take to build a silo capable of 6000 atm (88,175 PSI).

1986 GAO reports state "The Air Force is considering two basing modes using superhard silos which would be about 30 times harder than the current Minuteman III silos." which would put the silos themselves at around 30,000 or 60,000 PSI.

Public news articles state superhard silos for MX would be only 5,000 PSI.

Meanwhile, the Joint DOD/DOE Trident Mk4/Mk5 Reentry Body Alternate Warhead Phase 2 Feasibility Study Report (U) circa January 1994 stated:

"When the W88/Mk5 was developed, this was the assessed VNTK of the hardest Soviet silos. Although those SS-18 silos have since been assessed to be much harder than 7000 psi, the SPETWG considers 52L7 to be a significant figure of effectiveness for this system because of the history of its use."

So.... compromise around 10,000 PSI for superhard?

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Anyway...several years ago in 2017, I wrote a calculator for strategic bombardment to answer questions like this:

Strategic Bombardment Calculator

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If we assume we're using a Titan I from 1961 to attack enemy silos with:

3.75 MT warhead, 1280m CEP
system reliability of 75%
nuke reliability of 95%
PKill of 95% needed

we get the following numbers:

3 PSI: 5227m lethal radius, 3 missiles needed
25 PSI: 2578m lethal radius, 3 missiles needed
100 PSI: 1624m lethal radius, 5 missiles needed
1000 PSI: 754m lethal radius, 19 missiles needed
10,000 PSI: 350m lethal radius, 52 missiles needed

NOTE: The Titan I ICBM was originally rated as 50% reliable with the rating raised to 70% with the final Titan I squadrons. Overall, Titan I had a 77.61% Flight Reliability (52 successes, 15 failures).

================================================

If we assume we're using a Minuteman II from 1966 with the Mk 11C RV to attack enemy silos:

1.2 MT warhead, 550m CEP
system reliability of 95%
nuke reliability of 95%
PKill of 95% needed

we get the following numbers:

3 PSI: 3,575m lethal radius, 2 missiles needed
25 PSI: 1,763m lethal radius, 2 missiles needed
100 PSI: 1,111m lethal radius, 2 missiles needed
1000 PSI: 516m lethal radius, 6 missiles needed
10,000 PSI: 239m lethal radius, 17 missiles needed

NOTE: Minuteman over the years has achieved a 97.1% Flight Reliability (836 successes, 25 failures). It's also worth noting that in general public sources, the 17 October 1963 launch of a MINUTEMAN I was classified as a "success". This launch, classified CEDAR LAKE, was part of the Operational Test (OT) preceding induction of the Minuteman into SAC SIOP service and it actually missed the target by 24.26 nautical miles to the right and 781.37 nautical miles over.

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If we assume we're using a Minuteman III from 1970 with MIRVed warheads to attack enemy silos:

3 x 170 KT warheads, 185m CEP
system reliability of 95%
nuke reliability of 95%
PKill of 95% needed

we get the following numbers:

3 PSI: 1,864m lethal radius, 1 missile needed, 2 nukes needed, 1 spare nuke left over.
25 PSI: 919m lethal radius, 1 missile needed, 2 nukes needed, 1 spare nuke left over.
100 PSI: 579m lethal radius, 1 missile needed, 2 nukes needed, 1 spare nuke left over.
1000 PSI: 269m lethal radius, 1 missile needed, 3 nukes needed, no spare nukes.
10,000 PSI: 125m lethal radius, 3 missiles needed, 7 nukes needed, 2 spare nukes.

================================================

If we assume we're using a Trident II (D5) from 2000+ with MIRVed warheads to attack enemy silos:

4 x 90 KT warheads (New Start Limits)
14 x 90 KT Warheads (Maximum Throw Weight)
CEP is 70~ m (Trident II is claimed to have 50% improvement in CEP over Trident I's 90m CEP goal).
system reliability of 95%
nuke reliability of 95%
PKill of 95% needed

we get the following numbers:

For New START Loading:
1000 PSI: 217m lethal radius, 1 missile needed, 1 nuke needed, 3 spare nukes.
10,000 PSI: 101m lethal radius, 1 missile needed, 2 nukes needed, 2 spare nukes.

For Maximum Throw-Weight Loading:
1000 PSI: 217m lethal radius, 1 missile needed, 1 nuke needed, 13 spare nukes.
10,000 PSI: 101m lethal radius, 1 missile needed, 2 nukes needed, 12 spare nukes.

================================================

It's also worth noting that the bigger the missile - the bigger the silo needed; which is an issue once you get into superhardening.

There are also a whole bunch of other factors in play:

In 1966, it was really hard to get correctly geo-referenced data, unless you either sent out entire teams of surveyors or spent billions of dollars on spy satellites, both provenances of large nation states.

Now; a grad student working for an arms control think tank can buy public satellite images from imagery companies and "find" Chinese ICBM silos under construction.

Likewise, there are now multiple GPS constellations -- the US, EU, Russia, India, and China have, or will be putting their own ones up. You can get a pretty good "hack" of where you are now from the different GPS services; since I don't think the Russians selectively degrade GLONASS over US ICBM fields, unlike GPS. XD.

You can buy a laser-ring gyro for $3,500 to $10,000 off of Alibaba from Xi'an MH Electronics And Technology Co., Ltd. Just get in touch with Sales Engineer Sarah Du (sarah@mh-elec.com) and she'll give you a quote for your application!

Silos are also vulnerable to unconventional attack forces; per:

RDA-TR-4301-001
A SOVIET PARAMILITARY ATTACK ON U.S. NUCLEAR FORCES - A CONCEPT
NOVEMBER 1974
LINK

Detailed analyses show that Minuteman and Titan silo doors can be penetrated by a 40-pound shaped charge. Flammable fluids then poured through the breach caused by the shaped charge and ignited would assure catastrophic damage to the missile. Alternatively, a 75-pound shaped charge will penetrate the closure, the nose cone, and subtantially damage the missile warhead. Thus, the total amount of equipment required to destroy a Minuteman or a Titan is under 100 pounds and could be concealed and transported in the trunk of a small car.

Because the missile site has only one security fence and is otherwise unguarded, one man could destroy a missile within five minutes which is less than the response time of the base security guards, including those using helicopters, to arrive at all but a few silos. The response times for the more remote sites are potentially sufficient to allow an attacker to destroy several sites.

That was written in 1974.

With the prevalence of drones today, it wouldn't be too hard to design a drone that could be assembled from pieces carried in the trunk of a car, have a 20 mile range; and fly precisely into a missile silo door through image recognition and detonate a shaped charge in the drone's body to penetrate it.

A more overt cruise missile could be designed by a moderately advanced nation state to have intercontinental range; since the problems of long range navigation are solved now thanks to the tons of GPS networks.

Edit to add: also silos are super low maintenance. For the most part, fifty missiles require five two man teams. Compared to an SSBN it is fantastically cheap.
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Actually....no. You're falling into the classic trap here. You need to consider the entire weapons system, not just the weapon itself.

BLAND CORPORATION REPORT

For example:

A.) You'll need to launch three to four missiles a year to maintain reliability of the weapons system. That requires investment in Vandenberg AFB launch range and in Kwajalein target range.

B.) You'll need to fund a lot of things -- from 1992 to 2016, Minuteman III Total Annual Cost was $1.4B per year on average -- or about $2.8M per missile. Minuteman III is big enough you can spread the cost of $1.4B/yr for lots of things (helicopters, security force, etc) over a 500 to 400 missile force. Reducing the # of missiles bought will "frontload" a lot of this onto a smaller force.

C.) The entire ICBM force (3 wings of 450 missiles) in FY2010 had a total of 4,693 men; or 10.42 men per missile. It's hard to break down just exactly how many people would be needed, since there undoubtedly are positions which are needed, whether there are 400 missiles, or just 50.

D.) Because ICBM's are unrecallable and there's no movie "blow up in flight" code; a tremendous communications infrastructure must be built up to ensure positive control over the force; which "silent" spending which people don't consider.
 
Are you saying you believe siloed ICBMs are an obsolete strategic deterrent?
 
The infrastructure to maintain silo based missiles is still peanuts compared to SLBM costs on a per missile basis.
 
RyanCrierie said:
Josh_TN said:
One air force general noted astutely that if the US removes ICBMs from inventory, a percentage of the bomber force will have to be put on permanent nuclear alert again, which would probably require a significantly larger force of aircraft than currently planned as well as increased maintenance and readiness costs associated with that.
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I'd like to correct the USAF general's statement.

If the USAF wants to retain the slice of the budgetary pie it has now in regards to nuclear forces if it retires the ICBM force, it will have to put most of the bomber force back on nuclear alert, in order to keep X number of nuclear warheads under USAF control, lest that money go somewhere else, like two more Columbia-class SSBNs.
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The notion that getting rid of our ICBM for somehow makes us safe makes my head hurt. It absolutely, 100% DOES NOT MATTER, if they could drop a nuke right through the silo lid. What it does is raise the guaranteed cost to any potential adversary. In other words, it makes it LESS likely a war would even start.
 

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