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

Josh_TN said:
Well preferably I'd have an SSN do the sinking if at all practical, but I think we're giving Poseidon a lot of capabilities that haven't been ascribed to it in open source. It now has an active sonar system, enough AI to ID a particular target and follow it, and then has a torpedo it can fire at the target when it can sense its death...or perhaps simply detonates its nuke, because putting AI in charge of those decisions is a good idea...
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Not today but you're banking on SSBNs carrying the load for the next 30 - 50 years. A hell of a lot can change in that time.
 
Calphor said:
bobbymike said:
Calphor said:
Forest Green said:
Josh_TN said:
I'm hoping for four warheads as well; the artist rendering they've released show much less taper than MM3.

New START will expire Feb 2026 before Sentinel enters service. There is no mechanism to renew it and I think it will be the last strategic arms reduction treaty to exist for a long time given that any future agreement would likely have to involve China, which will complicate things at best and seems more likely to just be a non starter.
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I'm finding it difficult to get an accurate base diameter for Minuteman III, some sources say 1.68m, some 1.85m. If it's the latter with no taper for Sentinel, then it could hold 6 warheads.
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Considering that the US Air Force publishes MMIII diameter at 5.5 ft (1.67m), I would go with that. Sentinel will look very similar to MMIII. Think MMIII scaled up. It will not be uniform diameter like Peacekeeper or Trident C4/D5.
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If it’s a “new” MMIII what a waste and lost opportunity. If Russia builds more Sarmats than we expect and those 300 new Chinese silos hold 10 warhead Df-41s (not even including the mobile 10 warhead version) we have no ability to upload to any great degree the land based leg of the Triad.
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Not a “new” MMIII, it just resembles it from the outside. I don’t know what the load out will be, but it will be significantly more capable than MMIII. Not as capable as PK, but that is a given based on the tapered diameters of the stages. Remember that MMIII carried 3 MRVs/MIRVs for much of its deployed history. It was downloaded due to treaty obligations.

Based on the awarded contract, there will be a one to one replacement of Sentinel for current deployed MMIIIs.
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But those were SMALL warheads. You could never use a MM3 to launch an HTV-2 or Avangard for example, or even a multimegaton warhead.
 
sferrin said:
But those were SMALL warheads. You could never use a MM3 to launch an HTV-2 or Avangard for example, or even a multimegaton warhead.
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Not sure about the latter, the smaller MM2 had a 1.2MT warhead. Could you put a 2+MT warhead on the larger MM3 if your really wanted? Probably. On something slightly larger than a MM3? Definitely.

W78 weighed 320-360kg, so 1,000+ kg total for 3. Could you make a 1,000kg 2MT warhead? Very likely. In fact the W56 + RV only weighed 377kg and that was 1.2MT. Given how the achievable yield/mass ratio increases with size, with 1,000-1,100kg you'd be looking at 4-5MT.
 
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Forest Green said:
sferrin said:
But those were SMALL warheads. You could never use a MM3 to launch an HTV-2 or Avangard for example, or even a multimegaton warhead.
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Not sure about the latter, the smaller MM2 had a 1.2MT warhead. Could you put a 2+MT warhead on the larger MM3 if your really wanted? Probably. On something slightly larger than a MM3? Definitely.

W78 weighed 320-360kg, so 1,000+ kg total for 3. Could you make a 1,000kg 2MT warhead? Very likely. In fact the W56 + RV only weighed 377kg and that was 1.2MT. Given how the achievable yield/mass ratio increases with size, with 1,000-1,100kg you'd be looking at 4-5MT.
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There were two alternative Peacekeeper warheads, the Munster and Calmendro, yield of 800 & 600Kt respectively that were very similar in weight to the original W87. Although I haven’t been able to independently verify other than the Pk could carry ten of either.
 
Forest Green said:
sferrin said:
But those were SMALL warheads. You could never use a MM3 to launch an HTV-2 or Avangard for example, or even a multimegaton warhead.
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Not sure about the latter, the smaller MM2 had a 1.2MT warhead. Could you put a 2+MT warhead on the larger MM3 if your really wanted? Probably. On something slightly larger than a MM3? Definitely.

W78 weighed 320-360kg, so 1,000+ kg total for 3. Could you make a 1,000kg 2MT warhead? Very likely. In fact the W56 + RV only weighed 377kg and that was 1.2MT. Given how the achievable yield/mass ratio increases with size, with 1,000-1,100kg you'd be looking at 4-5MT.
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Could you fit a W53? Nope.
 
I don't particularly see the point in such large yield weapons - what specifically would be the target set?

In any case, should such a weapon become necessary presumably the US could weaponize Falcon 9 and dig out some new large silos for it as a sort of western Sarmat. That would carry any warhead you desired.
 
sferrin said:
Could you fit a W53? Nope.
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Doesn't need to to be multi-megaton. The W53 was an old design and was primarily dedicated to bunker busting, so it was more geared towards earth penetration than yield. The B41 was only 20% heavier (4800kg vs 4000kg) and packed almost 3 times the yield at 25MT vs 9MT.
 
Josh_TN said:
I don't particularly see the point in such large yield weapons - what specifically would be the target set?

In any case, should such a weapon become necessary presumably the US could weaponize Falcon 9 and dig out some new large silos for it as a sort of western Sarmat. That would carry any warhead you desired.
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Fission-fusion-quark fusion device. One hit and done.
 
Josh_TN said:
I don't particularly see the point in such large yield weapons - what specifically would be the target set?

In any case, should such a weapon become necessary presumably the US could weaponize Falcon 9 and dig out some new large silos for it as a sort of western Sarmat. That would carry any warhead you desired.
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Sure. That's like saying we don't need the NGAD and if we did we could just repaint a Gulfstream. They're just alike after all.
 
Forest Green said:
sferrin said:
Could you fit a W53? Nope.
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Doesn't need to to be multi-megaton. The W53 was an old design and was primarily dedicated to bunker busting, so it was more geared towards earth penetration than yield. The B41 was only 20% heavier (4800kg vs 4000kg) and packed almost 3 times the yield at 25MT vs 9MT.
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Yeah, you're missing the point. I DGAF about the W53. I used it as an example of a milti-megaton warhead. You could add a 3rd-stagre to the B83 and stuff that in an RV.
 
We need a few 100+Mt yield warheads for the Sentin…. I mean the asteroid deflect mission
 
bobbymike said:
We need a few 100+Mt yield warheads for the Sentin…. I mean the asteroid deflect mission
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Unless you make a really efficient quark fusion device that would be impossible without using anti-matter, which is extremely difficult to make and even more difficult to store.
 
sferrin said:
Yeah, you're missing the point. I DGAF about the W53. I used it as an example of a milti-megaton warhead. You could add a 3rd-stagre to the B83 and stuff that in an RV.
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I thought the point was a multi-megaton warhead. The difference in fatalities between a 4MT warhead and a 25MT on a certain foreign city of interest is only about 40%. What would the purpose of a larger warhead be?

nuclearsecrecy.com

NUKEMAP by Alex Wellerstein

NUKEMAP is a website for visualizing the effects of nuclear detonations.
nuclearsecrecy.com nuclearsecrecy.com
 
A 4MT warhead would allow you to miss by twice as far as a 500kT warhead but probably weighs more than 6 500kT warheads.

As regards double/triple-digit MT warheads, only something like NORAD would required that.
 
bobbymike said:
These are “advanced/modernized” versions of what is on the MMIII so it appears Sentinel will be a clone. What a wasted opportunity.
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Is our rocket industry, sans SpaceX, even capable of producing a clean sheet design?

What would a new design accomplish? Increased range or throw-weight?
 
isayyo2 said:
bobbymike said:
These are “advanced/modernized” versions of what is on the MMIII so it appears Sentinel will be a clone. What a wasted opportunity.
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Is our rocket industry, sans SpaceX, even capable of producing a clean sheet design?

What would a new design accomplish? Increased range or throw-weight?
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Yes.
 
Multi-megaton warheads are from an age when missiles couldn't hit shit. If you can do as much with a much smaller warhead you go with the smaller warhead, its as simple as that. The US did it, Russia is doing it, and China is in the process of doing it. Countries like to hold onto obsolete stuff for a long time but multi-megaton warheads are going the way of the dodo. Throwing billions of dollars into an expensive ICBM that can do an obsolete mission is the surest way to get stuck with MMIII for another 100 years.

As for Sarmat, Russia has no money, at this point its more likely they get less than they want than more.
 
All I can say is that Wikipedia doesn't know shit.

North Korea has how many deployed ICBMs? Testing is all fine and dandy buy deploying a big and expensive system like the Sarmat is another beast entirely.
 
Forest Green said:
Avangard is touted as 2MT on wiki.

en.wikipedia.org

Avangard (hypersonic glide vehicle) - Wikipedia

en.wikipedia.org en.wikipedia.org
web.archive.org

Шахты "Авангарда". Почему гиперзвуковые блоки решили ставить на Урале

РИА Новости, 18.12.2018
web.archive.org web.archive.org

It's also stated to travel faster than orbital velocity though... so there is that.
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Wiki's source for Avangard's speed is the title (Could Russia's Hypersonic Avangard ICBM Really Travel At 20-Times The Speed Of Sound?) of a National Interest piece, written by Kris Osborn ([...] has a Masters Degree in Comparative Literature from Columbia University), with the text of his piece offering exactly nothing to back up said figure. Clickbait title, possibly the product of an over-eager National Interest editor.

'No´ usually being the most likely answer to questions posed in clickbait titles.
 
Josh_TN said:
sferrin said:
bobbymike said:
These are “advanced/modernized” versions of what is on the MMIII so it appears Sentinel will be a clone. What a wasted opportunity.

rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
rocket.com rocket.com
www.rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
www.rocket.com www.rocket.com
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We all knew it would be. Apparently we're not allowed to say so. :rolleyes:
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You're saying it here, so apparently it is allowed. We'll bookmark this post and see if it gets taken down.
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They removed my previous reply to you. :rolleyes: I say "they" but I'd bet good money it was GTX.
 
sferrin said:
Josh_TN said:
sferrin said:
bobbymike said:
These are “advanced/modernized” versions of what is on the MMIII so it appears Sentinel will be a clone. What a wasted opportunity.

rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
rocket.com rocket.com
www.rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
www.rocket.com www.rocket.com
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We all knew it would be. Apparently we're not allowed to say so. :rolleyes:
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You're saying it here, so apparently it is allowed. We'll bookmark this post and see if it gets taken down.
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They removed my previous reply to you. :rolleyes: I say "they" but I'd bet good money it was GTX.
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The moderation of the posts was done by a moderator, with appropriate reasons given. The way to protest a moderator decision is by appealing to the site administrator, not throwing shade at moderators.
 
bobbymike said:
These are “advanced/modernized” versions of what is on the MMIII so it appears Sentinel will be a clone. What a wasted opportunity.

rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
rocket.com rocket.com
www.rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
www.rocket.com www.rocket.com
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Just because there were tests of “advanced/modernized” versions of MMIII stages does not mean that is what will be in Sentinel. Those motors were derived from a program that was looking at “drop-in” replacements for MMIII stages in the event that it was determined that MMIII would have the propulsions stages replaced again. The decision was made to go clean sheet and Sentinel was the result. It will be larger and more capable than MMIII. It will not, however, be as capable as Peacekeeper.
 
Calphor said:
bobbymike said:
These are “advanced/modernized” versions of what is on the MMIII so it appears Sentinel will be a clone. What a wasted opportunity.

rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
rocket.com rocket.com
www.rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
www.rocket.com www.rocket.com
Click to expand...
Just because there were tests of “advanced/modernized” versions of MMIII stages does not mean that is what will be in Sentinel. Those motors were derived from a program that was looking at “drop-in” replacements for MMIII stages in the event that it was determined that MMIII would have the propulsions stages replaced again. The decision was made to go clean sheet and Sentinel was the result. It will be larger and more capable than MMIII. It will not, however, be as capable as Peacekeeper.
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Sure it’s possible but every graphic depicts the exterior lines of the MMIII (even on the Air Force’s official website) plus with first test flight in 2023 what they are testing today seems relevant with the absence of them testing anything else.

Plus your statement seems quite definitive so if you have links or other information you can share the forum would appreciate it I’m sure.
 

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bobbymike said:
Calphor said:
bobbymike said:
These are “advanced/modernized” versions of what is on the MMIII so it appears Sentinel will be a clone. What a wasted opportunity.

rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
rocket.com rocket.com
www.rocket.com

Aerojet Rocketdyne

Aerojet Rocketdyne
www.rocket.com www.rocket.com
Click to expand...
Just because there were tests of “advanced/modernized” versions of MMIII stages does not mean that is what will be in Sentinel. Those motors were derived from a program that was looking at “drop-in” replacements for MMIII stages in the event that it was determined that MMIII would have the propulsions stages replaced again. The decision was made to go clean sheet and Sentinel was the result. It will be larger and more capable than MMIII. It will not, however, be as capable as Peacekeeper.
Click to expand...
Sure it’s possible but every graphic depicts the exterior lines of the MMIII (even on the Air Force’s official website) plus with first test flight in 2023 what they are testing today seems relevant with the absence of them testing anything else.

Plus your statement seems quite definitive so if you have links or other information you can share the forum would appreciate it I’m sure.
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While I would love to give you links with chapter and verse on the current specs for Sentinel, I cannot. I work for one of the GBSD subcontractors, so I do have definitive information, but I cannot share it because there has not been any official public descriptions of the missile stages. The first static test of a Sentinel stage (1st stage) is supposed to happen in early 2023 which should have some additional public release information on specs.

If you dig into the news release about the Aerojet test, it talks about an MCAT program which was a tech demonstration effort that followed a previous MCS3 (Medium Class Stage 3) program designed to test the limits of what new technologies could be inserted into a motor that fit the outer mold line of the MMIII 3rd stage.
 

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