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

[NMaude]

I wonder if you have seen official renderings and patches?

I have seen the official renderings however I understand that isn't the definitive appearance so that's why I'm asking as there doesn't appear to be much information available concerning the rocket-motors that will be used in the booster-stack.

 

[flateric]

What makes you think that this is not a 'definitive appearance'?

 

[NMaude]

What makes you think that this is not a 'definitive appearance'?

If it was its' definitive appearance wouldn't there be scale-models produced and photographs of ground tests of the rocket-motors?

 

[flateric]

I don't see any connection. It's like "B-21 official rendering was released in 2015, but I haven't seen any official scale models or ground engine runs vids, so it's not defenitive" in mid-2022.
More, NG has published SRM tests photos.

 

[NMaude]

More, NG has published SRM tests photos.

Thanks, I wasn't aware of those photos.

As for the drawing it's something that resembles a Minuteman I/II and doesn't seem definitive to me.

Edit: That photograph doesn't really show any details of the actual rocket-motor as it's obscured by the test-stand's structure.

 

[Scott Kenny]

It seems particularly foolish to step the rocket like that. Puts a very sharp limit on the bulk of what you can launch, regardless of the weight of the items.

For example, I doubt that a GBSD could carry more than 1 strategic HGV, while something like Trident could probably carry 3 or 4.

It also means that GBSD will never pack more than ~3x MIRVs/MaRVs.

 

[NMaude]

It seems particularly foolish to step the rocket like that. Puts a very sharp limit on the bulk of what you can launch, regardless of the weight of the items.

The other thing with having a constant diameter booster-stack is that it's aerodynamically cleaner and structurally more efficient.

 

[Scott Kenny]

The other thing with having a constant diameter booster-stack is that it's aerodynamically cleaner and structurally more efficient.

And, assuming the same total range/thrust per stage, shorter in overall length.

 

[bobbymike]

I prefer the silo stuffer myself

 

[A Tentative Fleet Plan]

Wouldn't be surprised if they reduced it to cut corners costs.

Given the accuracy of modern ICBMs, hardening the silos to the thousands or tens of thousands psi range is pointless and an entirely wasted expense. Hard Rock Silos were deemed a wasted investment with limited future viability even during the latter half of the Cold War.

 

[sferrin]

Given the accuracy of modern ICBMs, hardening the silos to the thousands or tens of thousands psi range is pointless and an entirely wasted expense. Hard Rock Silos were deemed a wasted investment with limited future viability even during the latter half of the Cold War.

Most ICBMs still aren't using terminally guided warheads so that's not necessarily true at all. And why make it easy for them? If you're so worried about it make them mobile. Oh, right, there's some physical law of the universe that says mobile ICBMs don't work in the US, unlike well, everywhere else on the planet that has ICBMs.

 

[A Tentative Fleet Plan]

Most ICBMs still aren't using terminally guided warheads so that's not necessarily true at all. And why make it easy for them? If you're so worried about it make them mobile. Oh, right, there's some physical law of the universe that says mobile ICBMs don't work in the US, unlike well, everywhere else on the planet that has ICBMs.

I'd happily build something like MX MPS across most of the Midwest.

 

[NMaude]

Given the massive budget blowout in the Sentinel programme it might make sense for the USAF to carve out the actual missile part of the programme, the LGM-35A itself, and segregate the funds so it isn't effected by it.

 

[sferrin]

Given the massive budget blowout in the Sentinel programme it might make sense for the USAF to carve out the actual missile part of the programme, the LGM-35A itself, and segregate the funds so it isn't effected by it.

Would be interesting to know if the .gov was wagging its finger at NG for infrastructure issues. (Are they even over that? Thought that was BAE.)

 

[NMaude]

Alex Hollings from Sandboxx has put out a video to do with the problems in fielding the MMIII replacement:

If replacing America's Minuteman III nuclear ICBMs was supposed to be the budget-friendly solution, it appears to have backfired, with the effort now projected to go at least 2 years behind schedule and at least 81% over budget.

But despite these historic cost overruns, the Pentagon has re-certified the new Sentinel ICBM program to continue, calling the effort essential to American national security.

So, let's talk about where these budget-busting costs are coming from, and the plan to overcome these challenges.

 

[Scott Kenny]

Most ICBMs still aren't using terminally guided warheads so that's not necessarily true at all. And why make it easy for them? If you're so worried about it make them mobile. Oh, right, there's some physical law of the universe that says mobile ICBMs don't work in the US, unlike well, everywhere else on the planet that has ICBMs.

Yeah, it's called people not wanting nukes in their backyard or traveling through their states.

I'm thinking the US is its own worst enemy.

Parts of it sure are.

 

[bobbymike]

A game plan for dealing with the costly Sentinel missile and future nuclear challenges

Enormous cost overruns have raised questions about how or if to go forward with the Sentinel, a new US intercontinental ballistic missile. The authors see five potential paths that might reduce costs. But to make the best military and financial choice, the United States will also have to...

thebulletin.org

 

[NMaude]

I'm looking forward to the first test-flight of the LGM-35.

 

[sferrin]

I'm looking forward to the first test-flight of the LGM-35.

I hope it has better luck than our hypersonics programs.

 

[Scott Kenny]

I hope it has better luck than our hypersonics programs.

I suspect it will work tolerably well. I mean, it's a solid rocket ICBM, we've been building the things for over 60 years now, and have been building composite wrapped solids since the 1980s with Trident 2.

The place I do have concerns is the business end. New warhead, new RBA, new guidance system.

 

[zjz]

How Northrop Is Working To Meet Solid Rocket Motor Demand​

How Northrop Is Working To Meet Solid Rocket Motor Demand | Aviation Week Network

The company is tripling its capacity at Maryland and West Virginia production facilities.

aviationweek.com

 

[bobbymike]

Air Force Looks to Cut Down on Sentinel Infrastructure Costs

Air Force officials say they are studying requirements for the Sentinel ICBM to possibly drive down infrastructure costs.

www.airandspaceforces.com

 

[sferrin]

Air Force Looks to Cut Down on Sentinel Infrastructure Costs

Air Force officials say they are studying requirements for the Sentinel ICBM to possibly drive down infrastructure costs.

www.airandspaceforces.com

This is just pathetic. They originally built the missiles AND the silos and now they can't manage upgrade the existing ones? They should hire China to do it. They don't have any difficulty there.

 

[Scott Kenny]

This is just pathetic. They originally built the missiles AND the silos and now that can't manage upgrade the existing ones? They should hire China to do it. They don't have any difficulty there.

Because the repairs needed exceed the cost of new construction.

 

[bobbymike]

This is just pathetic. They originally built the missiles AND the silos and now that can't manage upgrade the existing ones? They should hire China to do it. They don't have any difficulty there.

Look at from 1945 to 1965 when we built, for the first time (so many new technologies), a massive nuclear infrastructure with 35,000 warheads on dozens of platforms across strategic and tactical systems numbered in the thousands.

 

[A Tentative Fleet Plan]

Defence spending was between 7-10% of GDP over that period (aside from brief period after the Second World War, where the nuclear enterprise was run down). Said systems were also very technically immature with numerous teething problems, which was fine as the Soviet nuclear program was if anything, in an even worse position.

Of course I think GBSD should be cancelled and the money spent of buying more B-21s and putting NGAD into service, conventional general purpose forces are far more important, if the US needs Strategic Nuclear Forces it has the Navy for that.

 

[sferrin]

Of course I think GBSD should be cancelled and the money spent of buying more B-21s and putting NGAD into service, conventional general purpose forces are far more important, if the US needs Strategic Nuclear Forces it has the Navy for that.

That nicely torpedoes any credibility you had.

 

[bobbymike]

ICBM cost overrun a ‘collective failure’ of USAF, Northrop, DOD: Air Force’s chief buyer

Sentinel probably would’ve still blown its budget if Boeing hadn’t dropped out of competition, Hunter says.

www.defenseone.com

 

[A Tentative Fleet Plan]

That nicely torpedoes any credibility you had.

There are financial resource constraints, and conventional capabilities will be far more important for an US-China war over Taiwan (or indeed any proxy war between US forces and a Chinese-backed opponent, given the propensity for such conflicts in a Cold War), and given the need to conduct survivable conventional strike on the cheap with easily stockpiled munitions like JDAMs and Quickstrike Mines, I think the US needs much more than 100-200 B-21s, and needs large numbers NGADs to support them in the face of opposing 5th generation fighters.

Better to devote financial resources to that, than a system that solely seems to exist due to inter-service parochialism. I will outright state that I do not think GBSD will work as a warhead sink, it is unlikely that the Russians will target empty silos when they can hit more valuable cities, and the Chinese strategic nuclear forces have always had a counter-value role from the beginning, so aren't going to be targeting the silos in the first place. SSBNs seem to be relatively invulnerable, even with recent advances in blue-green lasers, especially given the amount of sea room they have to operate in. The position of ICBM silos and mobile ICBM garrisons and deployment areas will be known at all times, and the number of ancillary units (including command vehicles, support vehicles, mobile kitchens for the crew and security vehicles, see Stalking the Secure Second Strike: Intelligence, Counterforce, and Nuclear Strategy) required for mobile ICBMs, combined with associated electronic signatures mean they are far more vulnerable to being tracked than SSBNs, whose autonomy and active transmissions are minimal, not to mention the current US acoustic advantage over Chinese SSNs and limited quantity of high-quality Russian submarines. In terms of delivery systems SLBMs are as accurate and responsive as ICBMs, and in the US context, higher throw-weight, so there is no justification for ICBMs along those lines.

 

[sferrin]

There are financial resource constraints, and conventional capabilities will be far more important for an US-China war over Taiwan (or indeed any proxy war between US forces and a Chinese-backed opponent, given the propensity for such conflicts in a Cold War), and given the need to conduct survivable conventional strike on the cheap with easily stockpiled munitions like JDAMs and Quickstrike Mines, I think the US needs much more than 100-200 B-21s, and needs large numbers NGADs to support them in the face of opposing 5th generation fighters.

Better to devote financial resources to that, than a system that solely seems to exist due to inter-service parochialism. I will outright state that I do not think GBSD will work as a warhead sink, it is unlikely that the Russians will target empty silos when they can hit more valuable cities, and the Chinese strategic nuclear forces have always had a counter-value role from the beginning, so aren't going to be targeting the silos in the first place. SSBNs seem to be relatively invulnerable, even with recent advances in blue-green lasers, especially given the amount of sea room they have to operate in. The position of ICBM silos and mobile ICBM garrisons and deployment areas will be known at all times, and the number of ancillary units (including command vehicles, support vehicles, mobile kitchens for the crew and security vehicles, see Stalking the Secure Second Strike: Intelligence, Counterforce, and Nuclear Strategy) required for mobile ICBMs, combined with associated electronic signatures mean they are far more vulnerable to being tracked than SSBNs, whose autonomy and active transmissions are minimal, not to mention the current US acoustic advantage over Chinese SSNs and limited quantity of high-quality Russian submarines. In terms of delivery systems SLBMs are as accurate and responsive as ICBMs, and in the US context, higher throw-weight, so there is no justification for ICBMs along those lines.

Nice wall of text. ICBMs REQUIRE an enemy to attack your homeland, guaranteeing a response, and raising the threshold for an attack as high as possible. It's not about, "warhead sink" at all. I'd prefer they were mobile but we know how certain parties would get their panties in a bunch if we had those in the US. (Never mind that every other country on the planet, who has ICBMs, has them mobile.) And the notion that SSBNs will be impossible to detect, ever, is laughable.

 

[Forest Green]

That nicely torpedoes any credibility you had.

'Torpedoes' is absolutely correct, those submarines get torpedoed and that's your deterrent done if you have no ICBMs. With future plans for only 12 SSBNs, that's just too few eggs and too few baskets.

 

[A Tentative Fleet Plan]

SSBNs are not impossible to detect, but they much harder to detect than any other basing mode, assuming 1980s levels of silencing or better.

Other countries have mobile ICBMs to compensate for their low-quality SSBN forces and bad geography. The US has immediate access to the Atlantic and Pacific, it doesn't have to worry about the bad sonar conditions of the Barents Sea and South China Sea, nor the close proximity to hostile naval forces and air forces operating from Norway, Japan, the Philippines or Vietnam.

As for attacking the homeland, they will do that in a strategic exchange regardless, they're just going to devote their warheads to cities rather than silos.

 

[A Tentative Fleet Plan]

'Torpedoes' is absolutely correct, those submarines get torpedoed and that's your deterrent done if you have no ICBMs. With future plans for only 12 SSBNs, that's just too few eggs and too few baskets.

Anybody planning to do strategic ASW as a damage limitation strategy is also going to target the ICBM force and bomber bases.

This isn't putting all of your eggs in one basket, given the number of SSBNs and warheads they carry, even one surviving boat will cause unacceptable damage.

Given the acoustic advantages of US boats, it's likely that zero SSBNs will be killed, given how hard it is to track them.

 

[Forest Green]

Anybody planning to do strategic ASW as a damage limitation strategy is also going to target the ICBM force and bomber bases.

Takes a long time for missiles to reach 450 separate ICBM silos on CONUS and with warning aplenty - i.e. they'll be long gone by then.

This isn't putting all of your eggs in one basket, given the number of SSBNs and warheads they carry, even one surviving boat will cause unacceptable damage.

Given the acoustic advantages of US boats, it's likely that zero SSBNs will be killed, given how hard it is to track them.

I would hope that they are difficult to track but you can never be too sure about these things. What if a crew member is a second generation Russian illegal and decides to make it easier for instance?

 

[A Tentative Fleet Plan]

Takes a long time for missiles to reach 450 separate ICBM silos on CONUS and with warning aplenty - i.e. they'll be long gone by then.

Requires launch-on-warning though, which can be very dangerous in a crisis.

I would hope that they are difficult to track but you can never be too sure about these things. What it a crew member is a second generation Russian illegal and decides to make it easier for instance?

You could apply the same logic to the crewman of an ICBM TEL making a call on an unsecured mobile for the same reason.

Missile Silo crewman wouldn't have to worry about that though, as their position is already known.

SSBNs do have self-noise monitoring hydrophones, plus a large crew who do not share the saboteurs sympathies, so any technical means of trying to make the submarines sonar signature larger would be spotted very quickly. This is also likely going to be on one boat, not the entire force. Main problem would be a disgruntled individual within an office who hands over a bunch of classified documents covering patrol areas, but that could also apply to Mobile ICBMs or bomber dispersal.

 

[sferrin]

Requires launch-on-warning though, which can be very dangerous in a crisis.


You could apply the same logic to the crewman of an ICBM TEL making a call on an unsecured mobile for the same reason.

Missile Silo crewman wouldn't have to worry about that though, as their position is already known.

SSBNs do have self-noise monitoring hydrophones, plus a large crew who do not share the saboteurs sympathies, so any technical means of trying to make the submarines sonar signature larger would be spotted very quickly. This is also likely going to be on one boat, not the entire force. Main problem would be a disgruntled individual within an office who hands over a bunch of classified documents covering patrol areas, but that could also apply to Mobile ICBMs or bomber dispersal.

Why do launch on warning when you can do launch on confirmation of attack? I would not be surprised at all if we have the ability to image a launching missile. No more mistaking a forest fire for a launch. No more mistaking a sounding rocket for an ICBM. Does not matter one bit if the other guy knows the location of your silo to the millimeter. Do you think they would attack knowing they would get nuked in response? The same cannot be said for sinking an SSBN.

 

[Forest Green]

Requires launch-on-warning though, which can be very dangerous in a crisis.

There's a whole half hour from launch to strike.

You could apply the same logic to the crewman of an ICBM TEL making a call on an unsecured mobile for the same reason.

Except there's much less crew to vet and far more TELs.

Missile Silo crewman wouldn't have to worry about that though, as their position is already known.

But 30 minutes away from the enemy, and there are 450 active silos.

SSBNs do have self-noise monitoring hydrophones, plus a large crew who do not share the saboteurs sympathies, so any technical means of trying to make the submarines sonar signature larger would be spotted very quickly. This is also likely going to be on one boat, not the entire force. Main problem would be a disgruntled individual within an office who hands over a bunch of classified documents covering patrol areas, but that could also apply to Mobile ICBMs or bomber dispersal.

There's 12 boats and 150 crew. A single person sets something to make a delayed noise, moves on to somewhere else and repeats. It's not impossible to have one twat on nearly every boat.

Bottom line you need ICBMs and SSBNs... and some bombers for telling people you're annoyed.

 

[Grey Havoc]

I would hope that they are difficult to track but you can never be too sure about these things. What if a crew member is a second generation Russian illegal and decides to make it easier for instance?

Not to mention things like logic bombs in the most unexpected of places. Though to be fair, the ICBMs and the bombers may be vulnerable to such attacks as well, given the amount of corner-cutting and outright corruption in the 30 years or so.

 

[Grey Havoc]

Air Force going ‘line by line’ to bring down nuclear missile costs

The Air Force "neglected" the complexity of the LGM-35A Sentinel's ground infrastructure, officials said, and is now looking to bring down costs.

www.defensenews.com

 

[Dreamfighter]

Of course I think GBSD should be cancelled and the money spent of buying more B-21s and putting NGAD into service, conventional general purpose forces are far more important, if the US needs Strategic Nuclear Forces it has the Navy for that.

Maybe just double the planned SSBNs to be build and give the extra ones to the USAF so they can put those on land where the old ICBM silos are located. Everybody happy.