Sentinel ICBM will need mostly new Silos...

[MKSheppard]

https://breakingdefense.com/2025/05/air ... new-silos/

Air Force now expects Sentinel ICBMs will ‘predominantly’ need new silos

“Part of the requirements, initially — ten years ago when this program was started — was to reuse the holes, the missile holes at the launch facilities,” said Air Force Gen. Thomas Bussiere. “Shockingly enough, if we look at it, that may not be the answer.”

By Michael Marrow on May 05, 2025 at 11:42 AM

WASHINGTON — The Air Force now believes its new nuclear intercontinental ballistic missiles will “predominantly” require digging fresh missile silos, a significant change of plans to reuse existing silos and a move the service has previously assessed will come with major costs.

To house the new Sentinel ICBM, officials previously planned to refurbish 450 existing silos currently used by the Sentinel’s predecessor, the aging Minuteman III (MMIII). But as the Pentagon works through a cost breach analysis for Sentinel after its price tag ballooned last year, officials now expect existing silos will largely not be reusable after all.

“The Air Force continues to assess its options and design concepts as part of doing good systems engineering. While no decision has been made, we expect Sentinel to use predominantly AF-owned real estate to build new missile silos instead of re-using MMIII silos,” an Air Force spokesperson told Breaking Defense.

The Sentinel’s prime contractor, Northrop Grumman, referred a request for comment to the Air Force.

When the Pentagon certified Sentinel to continue last year amid a cost breach known as Nunn-McCurdy, officials explained that they would adopt changes to launch facilities, which would make them “more cost-effective as well as less complex.” Yet digging new silos would represent a dramatic change, particularly because a previous analysis of alternatives conducted around the time of the program’s inception reportedly found that doing so would incur prohibitive costs. Defense Daily previously reported the potential silo switchup, citing dialogues Air Force leaders have held with local communities.

The Sentinel program aims to procure 634 missiles — along with an additional 25 for development and testing — and deploy 400 of them in silos spread across vast missile fields in the Great Plains, stretching from Colorado to North Dakota near the Canadian border. A need to dig new silos means hundreds may have to be built.

During remarks at the Advanced Nuclear Weapons Alliance Deterrence Center on April 30, Air Force Global Strike Command chief Gen. Thomas Bussiere explained reusing the MMIII silos may not be feasible.

“Part of the requirements, initially — ten years ago when this program was started — was to reuse the holes, the missile holes at the launch facilities. That was believed to be more efficient, more cost effective and quicker,” Bussiere said. “Shockingly enough, if we look at it [now], that may not be the answer.” A decision has not been made, the general emphasized.

Sentinel has four different segments, according to Bussiere: command and launch consisting of facilities like silos and command centers; the missile itself; the missile’s payload; and support equipment. Officials have said the launch facility segment, consisting of the large-scale silo construction work and attendant features like modern cabling and new buildings, is the chief source of a roughly 81 percent budget breach and a new price tag of $141 billion. The program’s woes have also pushed back initial operational capability several years beyond an original 2029 forecast.

Upgrading the ICBMs are part of a massive nuclear modernization effort that one government organization says will cost $946 billion over the next decade.

Bussiere explained that officials are currently exploring different paths forward under Nunn-McCurdy, where “part of this process … is to look at the viability of using the same landscape, but potentially looking at maybe doing a different hole for the weapon, versus reusing the current hole,” he said.

The general then stated that officials are “pretty seriously” considering a plan to “reus[e] federal lands” that are “within our current footprint in our missile wings.” Calling the land “green fields,” Bussiere said that some of that land still in possession of the federal government could be utilized to “potentially expand our sequential fielding.” (Part of Sentinel’s vast construction is expected to require the federal government to negotiate easements with private property owners.)

“As we transition from the Minuteman III to the Sentinel… we have to maintain our minimum numbers of ICBMs on alert for the nation,” Bussiere said. “And that’s going to be a graceful ballet between ops and maintenance, acquisition, you know, a bunch of partners that are part of this program to make sure we get this right.”

[MikeKozlowski]

....Somebody in a blue suit needs to tell me NOW why we can't use the existing holes. If the missile can't/won't fit, that's Boeing's problem. If the holes can't be used because of their condition then the entire USAF leadership from the CSAF down need to be held responsible.

Mike

[Kunkmiester]

Amen.

Gotta wonder though, I remember reading on here some silos were set up carefully so they would be shielded by geography from attack while allowing launch against the USSR, and some of those missiles couldn't be repurposed for other targets.

If they intend to have a more generally useful force, how many of those couldn't be used? Assuming that's not finger breaking territory.

[MikeKozlowski]

Amen.

Gotta wonder though, I remember reading on here some silos were set up carefully so they would be shielded by geography from attack while allowing launch against the USSR, and some of those missiles couldn't be repurposed for other targets.

If they intend to have a more generally useful force, how many of those couldn't be used? Assuming that's not finger breaking territory.

Kunk,

If that's true then I can understand not using those silos - they might be perfectly good for launching MMIII, but even if a Sentinel was absolutely compatible with it in physical terms it's going to fly differently. That makes sense at least, but there can't be that many of those holes.

Mike

[Johnnie Lyle]

....Somebody in a blue suit needs to tell me NOW why we can't use the existing holes. If the missile can't/won't fit, that's Boeing's problem. If the holes can't be used because of their condition then the entire USAF leadership from the CSAF down need to be held responsible.

Mike

Especially in light of the M10 cancellation for being too fat.

This smacks of bad project management and worse communication skills.

[James1978]

....Somebody in a blue suit needs to tell me NOW why we can't use the existing holes. If the missile can't/won't fit, that's Boeing's problem. If the holes can't be used because of their condition then the entire USAF leadership from the CSAF down need to be held responsible.

Mike

Mike,
From what I've picked up from the Sentinel thread over at Secret Projects, the missile isn't the problem. That part of the program seems to be on track, and the missile fits.

And the problem is less the silos themselves, than the LCCs. We're talking about underground sites that are 50+ years old . . . and all the cabling between the LCCs and the silos that has been underground for 50+ years. Apparently when they started to open up walls, get into the cabling, etc., things were in worse shape than expected. To the degree that refurbishing existing silos and LCCs may cost significantly more than just building new silos and LCCs.

[MFOM]

Is there anything saying they must all be silo based? Couldn't we look at road mobile for at least some portion, cause rebuilding every silo is going to be more expensive then whatever they say it's going to be

[James1978]

Article from September 2024.
Follow some of the links.

Basically, they hoped to reuse the communications infrastructure, but it's too old and lacks the necessary bandwidth for modern needs. It seems we're looking at 7,500 miles of cabling. Nobody realized just how bad a shape a lot of the underground stuff was when they costed the program.

USAF Going ‘Line by Line’ to Slash Sentinel’s Rocketing Costs
Sept. 5, 2024 | By Greg Hadley

Air Force officials are re-examining the infrastructure overhaul that sent costs soaring over plan for the next-generation Sentinel intercontinental ballistic missile upgrade.

USAF leaders have blamed the massive infrastructure overhaul for “critical” cost and schedule misses and now say they are going “line by line” through every requirement to simplify their plans and drive down runaway costs. Pentagon acquisition and sustainment chief William LaPlante had to certify the necessity to continue work on Sentinel after cost-overruns triggered a Nunn-McCurdy Act review.

In certifying Sentinel, however, LaPlante rescinded the program’s Milestone B decision, delaying it from going into engineering and manufacturing development. Instead, he ordered the Air Force to develop a restructuring plan.

Vice Chief of Staff Gen. James C. “Jim” Slife and Assistant Secretary of the Air Force for Acquisition, Technology and Logistics Andrew P. Hunter said at a Defense News conference Sept. 4 that they are making a thorough examination of Sentinel’s requirements.

“I just spent an afternoon going through requirements, line by line,” Slife said. “I mean, this is going to be going on for, you know, for months and months, but absolutely it is down to that level of detail. And it’s not just the top-level requirements. The top-level requirements are fairly easily understood. It’s the derived requirements that actually can become problematic.”

The need to modernize the aging land-based leg of the nuclear triad to provide a strategic deterrent to nuclear war is well understood; it’s the flow of choices that follow that pose the challenges where costs start to multiply, with the projected cost of the program having ballooned from $95.3 billion to $140.9 billion

Each decision builds on a prior one. One requirement choice means “you’re going to need a facility that is this big, and if you’re going to need a facility that big, here’s how much concrete it’s going to take,” Slife explained. “And if it’s going to take that much concrete, you’re going to have to have a workforce. It’s working it all the way down until you understand exactly where the cost drivers are in the program.”

Sentinel is meant to be a complete replacement for the Minuteman system—and while the Minuteman III missiles were first fielded in 1970, the launch centers, support facilities, cabling, and other infrastructure date back even further, to the early 1960s.

“The tendency is to focus on the missile,” Hunter said. “In fact, that was how we did the program initially—we focused on the missile. And we really neglected the complexity of the ground infrastructure.”

Retired Col. Jennifer Reeves, a former ICBM wing commander who is now a senior resident fellow at the Mitchell Institute for Aerospace Studies, said the Air Force only started doing depot-level maintenance on launch and launch control facilities in 2017—more than 50 years after they were first activated.

The failure to think more about ground facilities belies their importance, she said. “An airplane can just go fly in the air anywhere,” she said. “You don’t need the actual structure that the airplane lives in to fly the airplane, which is not the case with the missile. Without the silo, there’s no way to launch it. There’s no way to operate it. They are umbilically connected.”

Hunter said that was clear on a recent visit to Malmstrom Air Force Base, Mont., where he went with Undersecretary of the Air Force Melissa Dalton.

“When you look at the complexity of the current ground infrastructure, and you think about what we ask it to do, we don’t just have a missile,” Hunter said. “We have to have a deterrent. So we have to have a missile where we can respond instantly, at all times, without fail, and in the context of the highest of high-intensity conflicts. … We ask our ground infrastructure essentially to provide most of those capabilities. The missile itself is only a small piece of that puzzle. It’s a very challenging requirement, and it’s instantiated in this ground infrastructure.”

Hunter said the Air Force will bring “a lot of engineering focus” to the ground infrastructure and appeared hopeful that savings would be found.

“[We can] change our design for the ground infrastructure to be simpler, more affordable,” he said. “We’ll work closely together with the operational committee on the requirements to make sure we’re still doing what it takes to deliver nuclear deterrence, but in an affordable way.”

Slife offered an example of the tradeoffs: Security can be physical, or it can rely on manpower. One costs more up front, the other costs more over time. Officials have also previously said the Sentinel launch control facilities will be larger than the Minuteman ones, which could require more construction costs. And Reeves noted that the plan already was to move from five launch control centers per squadron to three, simplifying the overall system.

Still, there is a limit to how much can be simplified. Asked if the service still planned to replace the copper cable used for communications and connectivity with advanced fiber optic cables, Hunter quickly responded that “we do see that as part of the solution going forward.”

[MFOM]

Just like peacekeeper, with missiles ready to go and nowhere to put them

[MikeKozlowski]

....Somebody in a blue suit needs to tell me NOW why we can't use the existing holes. If the missile can't/won't fit, that's Boeing's problem. If the holes can't be used because of their condition then the entire USAF leadership from the CSAF down need to be held responsible.

Mike

Mike,
From what I've picked up from the Sentinel thread over at Secret Projects, the missile isn't the problem. That part of the program seems to be on track, and the missile fits.

And the problem is less the silos themselves, than the LCCs. We're talking about underground sites that are 50+ years old . . . and all the cabling between the LCCs and the silos that has been underground for 50+ years. Apparently when they started to open up walls, get into the cabling, etc., things were in worse shape than expected. To the degree that refurbishing existing silos and LCCs may cost significantly more than just building new silos and LCCs.

James,

Absolutely agree on the age of the holes; they go back to the beginning of the program. But in the mid 80s, the silos were pretty much completely rewired. I know, 40 years instead of 50 ain't much of an improvement. I think though that one of my points still stands - if the silos were in that bad a condition, that was something that should have been addressed long ago, probably starting about fifteen or so years ago. OTOH, fifteen years ago we were spending money on the GWOT and the strategic side of the house had been reduced to red-headed stepchild status....

Mike

[James1978]

Is there anything saying they must all be silo based? Couldn't we look at road mobile for at least some portion, cause rebuilding every silo is going to be more expensive then whatever they say it's going to be

Ten years ago I'd have said sure, let's go mobile.

Today? No. If we're not already there, we're rapidly approaching the point where satellite constellations will offer damn near 24/7/365 coverage of the whole world. And that's before we talk about drones.

Back in the 1980s, they were looking at deploying on tracts of DOD owned land. All well and good. But it rather narrows down where to look. Sure, in theory, they could deploy onto vast tracts of BLM owned land. But that land isn't actually empty.

Anybody ever look up what the traveling circus that accompanied a GLCM flight back in the 1980s looked like?
Now put that in the 2020s-2060s in the continental United States . . . with drones. And "peace protestors" who follow them around and broadcast their location for world peace.

The siting report from the MGM-134 program back in 1985 make for interesting reading. Mobile doesn't quite mean what you think it means.
* Executive Progress Report on Small ICBM Siting and Basing Options
* Small ICBM Area Narrowing Report. Volume 1. Hard Mobile Launcher in Random Movement Basing Mode
* Small ICBM Area Narrowing Report. Volume 2. Hard Mobile Launcher at Minuteman Facilities Basing Mode

[James1978]

FYI - Sentinel is a Northrup-Grumman program. Boeing dropped out of the competition in 2019.

For what it's worth, here is an earlier thread about the program started in November 2023
Strategic Weapons: Sentinel Replacing Minuteman...

And some links I've collected on the program if anyone is interested in recent program history.
US Minuteman III missile replacement breaks $96 billion budget, triggers Pentagon review (19 January 2024)
US Air Force tests third-stage rocket motor for next nuclear missile (20 March 2024)
Northrop says Air Force design changes drove higher Sentinel ICBM cost (28 March 2024)
Sentinel ICBM’s first flight test slips to 2026: Air Force (28 March 2024)
LaPlante: ‘Nunn-McCurdy Or Not,’ US Must Have ICBM Leg of Triad (15 May 2024)
As new ICBMs' cost soars, a few lawmakers are trying to rein it in (5 June 2024)
Lawmakers Want Briefing on Fund That Could Take Sentinel Off the Air Force Books (17 June 2024)
USAF Going ‘Line by Line’ to Slash Sentinel’s Rocketing Costs (5 September 2024)
ICBM cost overrun a ‘collective failure’ of USAF, Northrop, DOD: Air Force’s chief buyer (5 September 2024)

[Pdf27]

I have a theory. There were originally 1,000 Minuteman silos, of which 400 are currently in use. The most recent tranche of 50 silos were de-activated in 2015. I rather suspect that the plan was to do a shuffle whereby they refurbished 50 silos at a time and put new missiles in them before decommissioning and re-purposing the Minuteman silos freed up. If they found something nasty in those first 50 silos - and wiring is a very good candidate since otherwise it's just a big hole in the ground - then the whole schedule is in a mess and you look at digging new holes as a more cost-effective solution.

[Kunkmiester]

Wires or conduit? I can't imagine a modern system would use cables from the 80s (I would think it'd be based on modern Ethernet or fiber optic stuff), so I'd think it would be less the actual wiring as being able to actually replace it.

[Straker]

Wires or conduit? I can't imagine a modern system would use cables from the 80s (I would think it'd be based on modern Ethernet or fiber optic stuff), so I'd think it would be less the actual wiring as being able to actually replace it.

Probably something nasty used as wire insulation or fire/smoke proofing at cable entries. Like with most things e.g. Asbestos used as fire proofing at cable entries it is absolutely fine until you need to run a new cable then a massive pain. The solution for a lot of retrofits on buildings here is just to drill walls and run new conduit or trunking which I can imagine being infinitely harder underground.

Or it could be something as simple as lots of the cables being run in MICC or the US equivalent which is a massive pain to replace as it isn't really flexible and tends to break and drop oxide powder everywhere.

Even with the massive increase in construction costs compared to general inflation new builds can come in a lot cheaper through the life of the structure even with a higher up front cost although I doubt that is the question here.

[Calder]

I am starting to lean toward just getting rid of the land based ballistic missile leg of the Triad. 90% of its mission can be performed by the Ballistic missile submarines and they have capabilities that the land-based missiles don't have. Bombers can be the backup to the Navy, and bombers can perform non-nuclear missions that the other two can't.

I would rather spend the money on conventional forces.

[Demon Lord Razgriz]

I am starting to lean toward just getting rid of the land based ballistic missile leg of the Triad. 90% of its mission can be performed by the Ballistic missile submarines and they have capabilities that the land-based missiles don't have. Bombers can be the backup to the Navy, and bombers can perform non-nuclear missions that the other two can't.

I would rather spend the money on conventional forces.

I'd agree with this if the funding was shifted to maintenance for the Navy, get those ships out of the ditch they're in, but the USAF would do everything in their power to prevent that.

[Paul Nuttall]

Can they be air launched....asking for a friend....

[jemhouston]

Can they be air launched....asking for a friend....

Yes



https://www.youtube.com/watch?v=96A0wb1 ... vaksoldier

This would be a good time to wish the C-17 was still in production.

[Nik_SpeakerToCats]

Didn't the B-52 re-furb program run into similar ghastly issues with cabling?

And let's not forget Apollo#1, where each modification just had more and yet more wire run until it was literally being crammed in...