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

Hood said:
Looks like even the missile designation system is broken now too.
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Skipping from MQM-178 to AIM-260 did suggest that might already be the case, to be fair. It was at least possible that there were 80-odd classified designations, if unlikely.

Notwithstanding silly designations, the USAF illustrations are interesting if accurate. They suggest that the missile may be installed in new, hot-launch siloes, with new launch control centres. That's a significant step away from Minuteman, and indicates substantially different missile capability and survivability.
 
RLBH said:
Hood said:
Looks like even the missile designation system is broken now too.
Click to expand...
Skipping from MQM-178 to AIM-260 did suggest that might already be the case, to be fair. It was at least possible that there were 80-odd classified designations, if unlikely.

Notwithstanding silly designations, the USAF illustrations are interesting if accurate. They suggest that the missile may be installed in new, hot-launch siloes, with new launch control centres. That's a significant step away from Minuteman, and indicates substantially different missile capability and survivability.
Click to expand...
Minutemen are in hot-launch silos. It's EXTREMELY unlikely GBSD will be anything but a small, hot-launch missile using existing silos. I'd be surprised if it weren't intentionally sized so as to only be able to carry a single Mk21 RV.
 
RLBH said:
Hood said:
Looks like even the missile designation system is broken now too.
Click to expand...
Skipping from MQM-178 to AIM-260 did suggest that might already be the case, to be fair. It was at least possible that there were 80-odd classified designations, if unlikely.

Notwithstanding silly designations, the USAF illustrations are interesting if accurate. They suggest that the missile may be installed in new, hot-launch siloes, with new launch control centres. That's a significant step away from Minuteman, and indicates substantially different missile capability and survivability.
Click to expand...
As far as I know existing silos and control centers are being renovated. I haven't seen hot launch confirmed but it seemed likely. The missile appears to be more MMIII in size and arrangement than the MX, which was cold launched from MM silos because it was too large for a hot launch in the existing infrastructure.

It doesn't look like the new missile is a dramatic change in capability or throw weight to me.
 
sferrin said:
Minutemen are in hot-launch silos. It's EXTREMELY unlikely GBSD will be anything but a small, hot-launch missile using existing silos. I'd be surprised if it weren't intentionally sized so as to only be able to carry a single Mk21 RV.
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Yeah, looking at the CGI again it does appear to closely match the Minuteman III silo; I'd mistakenly thought they had quite a different door configuration. The LCC does look to be a substantially new design, though - I'm sure I've seen assessments before that the LCCs are the least-hard part of the system, so that makes sense.

I'd agree wholeheartedly on the sizing; given that the Minuteman III is appreciably more capable than that, with older technology, I'd expect the new missile to be substantially smaller. Midgetman did a single Mk.21 in less than half the weight of a Minuteman thirty years ago, so that'd be my opening guess.
 
It looks to be MMIII sized, but hopefully with mildly improved throw weight. My concern is that it doesn't seem substantial wider, which will always limit the total number of RVs and/or size of the RVs.
 
Josh_TN said:
It looks to be MMIII sized, but hopefully with mildly improved throw weight. My concern is that it doesn't seem substantial wider, which will always limit the total number of RVs and/or size of the RVs.
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They really missed the ball here. I'm guessing they just wanted to check the box, so they could say they did, and weren't actually looking for useful capability.
 
I think it is fair to say they were looking for a 1:1 replacement with the least upgrades to infrastructure, yes. It probably maintains the ICBM force as a fallback deterrent were SSBNs suddenly to become vulnerable, so it "checks the box" without bringing nothing new to the table. That's probably adequate for the foreseeable future, particularly given the problems Russia is going to have maintaining its current posture. At some point it may prove inadequate vis-a-vis China, and result in some kind of crash development program for an MX like weapon to increase capability. Time will tell.
 
ICBMs are missile sponges, you do not need them to be MIRVed. Single warhead ICBMs are stabilizing while MIRVed ones are destabilizing. That said, I'd be surprised if GBSD can't be uploaded to 3 Mk12As. If GBSD can deliver a single Mk21 accurately and reliably, it will be doing its job. Its alot more important that the infrastructure is upgraded and made more survivable.
 
I'm well aware of the disposition of other nuclear powers. None of them have the number of SSBNs, sortie rates, tubes per SSBN, or RVs per SLBM of the United States. The US deterrent is largely sea based and as numerous as the nearest competitor, with the entire ICBM/SLBM force being capable of of more or less doubling in RV size if warheads in storage were uploaded to the existing missile base (if New START were ignored or expired). So while the Sentinal doesn't seem particularly impressive, it seems sufficient for the role ICBMs fill in the US nuclear triad: nuclear sponge and fallback position in the event SSBNs suddenly become less relevant.

As for mobile launchers, I wouldn't want to bet on that type of basing being safe in the medium to long term. The US Army is already experimenting with using AI to analyze commercial satellite imagery to identify targets for long range precision artillery. They have already tested this methodology in Project Convergence 2021 and apparently lowered engagement times to minutes or even seconds. It isn't that much of a leap for the same AI tech and satellite proliferation to be used to detect the uniquely massive mobile launchers used for ICBMs (along with the large security element that is necessary to deploy them in the field). I think getting into the mobile ICBM game now is too little too late; it is a deployment method that is going to face obsolescence as ISR becomes more low signature and more ubiquitous.
 
Josh_TN said:
I'm well aware of the disposition of other nuclear powers. None of them have the number of SSBNs, sortie rates, tubes per SSBN, or RVs per SLBM of the United States.
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1. Not yet. 2. All your eggs in what, 7 baskets? Tops. 3. Less deterrent value than ICBMs.

Josh_TN said:
The US deterrent is largely sea based and as numerous as the nearest competitor, with the entire ICBM/SLBM force being capable of of more or less doubling in RV size if warheads in storage were uploaded to the existing missile base (if New START were ignored or expired). So while the Sentinal doesn't seem particularly impressive, it seems sufficient for the role ICBMs fill in the US nuclear triad: nuclear sponge and fallback position in the event SSBNs suddenly become less relevant.
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A sunk SSBN is less likely to elicit the same response as the equivalent number of warheads nuked on US soil. Likely they could sink one and get away with it completely.

Josh_TN said:
As for mobile launchers, I wouldn't want to bet on that type of basing being safe in the medium to long term.
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Far safer than static silos. If you want to keep silos at least defend them.

Josh_TN said:
They have already tested this methodology in Project Convergence 2021 and apparently lowered engagement times to minutes or even seconds.
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LOL. Unless you have a megawatt class laser overhead there's no way "seconds" is even remotely on the table. And if you think AI is going to make it easier to detect mobile ICBMs, imagine how easily it would detect an attack. Russian/Chinese TELs would be empty by the time an attacking warhead got there.
 
Silo vs mobile: the mobile missiles are far more vulnerable to near hits. I was under the impression regiments still dispersed into batteries rather than individual launchers. In any case, a large detonation could knock out an unprotected launcher hundreds or even thousands of meters away from its impact point, so launcher separation would have to be quite distant to prevent multiple missiles from being engaged by a single aim point. The only security in mobile basing is the assumption that the deployment cannot be detected in real time. I don't think that will be the case by the end of the decade. Silo basing at least requires a certain amount of accuracy and/or warhead size to be countered and risks only one missile per aim point.

We'll agree to disagree on the relatively survivability of SSBNs; I consider a superior form of deployment to any land based scheme.
 
Josh_TN said:
Silo vs mobile: the mobile missiles are far more vulnerable to near hits.
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Depends on the TEL. Midgetman, while not as hard as a silo, was much harder than your average TEL. A silo is more likely to suffer a incapacitating hit as they know exactly where it is. The reason silos have deterrent value is because you actually have attack the other guy's homeland. An SSBN sunk at sea doesn't have the same impact on the headlines. Mobile ICBMs give you the best of both worlds, which is why everybody else is using them (and why the US intended to use them before the "Peace Dividend".

 
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Silo ICBMs require nukes to take out, mobile ICBMs do not, a conventional cruise missile can take them out. Also the Russian mobiles are not permanently deployed, only a handful of regiments are out at any one time. An entire mobile ICBM division can be taken out by just 1-3 warheads. Also the US has 400 silo targets, while Russia only has 150ish road-mobiles, less targets need less warheads.

If you want the best of road-mobiles, you need hardened individual shelters for the TELs with plenty of extra shelters to serve as decoys, and yes it will be alot more expensive than silos.

Don't forget, road-mobiles are Russians primary retaliatory means, land-based ICBMs are not the US primary nuclear force.
 
There will be a Minotaur II+ launch to support Sentinel development. This will be the first launch since 2008. No idea why it calls the Sentinel the LGM-35A as isn’t it the LGM-182?

This is the first test supporting the development of the Air Force's new Mk21A re-entry vehicle that will be used on the future LGM-35A Sentinel intercontinental ballistic missile, according to officials.

Both are being developed by the Air Force Nuclear Weapons Center.

The launch is intended to demonstrate "preliminary concepts and relevant payload technologies in operationally realistic environments," according to officials.
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keyt.com

Test rocket launch scheduled from Vandenberg Space Force Base Thursday morning

An unarmed test launch of a Minotaur II+ Rocket is planned to take off from Vandenberg Space Force Base sometime on Thursday morning.
keyt.com keyt.com
 
Flyaway said:
There will be a Minotaur II+ launch to support Sentinel development. This will be the first launch since 2008. No idea why it calls the Sentinel the LGM-35A as isn’t it the LGM-182?

This is the first test supporting the development of the Air Force's new Mk21A re-entry vehicle that will be used on the future LGM-35A Sentinel intercontinental ballistic missile, according to officials.

Both are being developed by the Air Force Nuclear Weapons Center.

The launch is intended to demonstrate "preliminary concepts and relevant payload technologies in operationally realistic environments," according to officials.
Click to expand...
keyt.com

Test rocket launch scheduled from Vandenberg Space Force Base Thursday morning

An unarmed test launch of a Minotaur II+ Rocket is planned to take off from Vandenberg Space Force Base sometime on Thursday morning.
keyt.com keyt.com
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https://twitter.com/x/status/1544957838161629185
View: https://twitter.com/ryankakiuchan/status/1544957838161629185
 
Obviously going to be a single warhead design how much RV upload will be available on Sentinel is still opaque.

IMHO Sentinel should be Minotaur V sized but I digress.
 
sferrin said:
Josh_TN said:
Silo vs mobile: the mobile missiles are far more vulnerable to near hits.
Click to expand...
Depends on the TEL. Midgetman, while not as hard as a silo, was much harder than your average TEL. A silo is more likely to suffer a incapacitating hit as they know exactly where it is. The reason silos have deterrent value is because you actually have attack the other guy's homeland. An SSBN sunk at sea doesn't have the same impact on the headlines. Mobile ICBMs give you the best of both worlds, which is why everybody else is using them (and why the US intended to use them before the "Peace Dividend".

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Believe this video was shot at Malmstrom Air Force Base... late 1980s?
 
Be a nice vehicle to carry two IRBMs in the European theater or in the Australian outback.

Yes I “get” that will never happen but a guy can dream ;)
 
Tangential: The 'Sentinel' design with but one (1) MIRV-type head... Call it the 'Skinny-man' ??
 
Nik said:
Tangential: The 'Sentinel' design with but one (1) MIRV-type head... Call it the 'Skinny-man' ??
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That's basically what it is. Think Midgetman-light. Will almost certainly be the least capable "ICBM" on the planet it when (if) it ever gets fielded. It'd almost be better to keep MM3.
 
sferrin said:
Nik said:
Tangential: The 'Sentinel' design with but one (1) MIRV-type head... Call it the 'Skinny-man' ??
Click to expand...
That's basically what it is. Think Midgetman-light. Will almost certainly be the least capable "ICBM" on the planet it when (if) it ever gets fielded. It'd almost be better to keep MM3.
Click to expand...

Have the requirements or dimensions ever been published? The documentation I’ve read quite explicitly threw out the idea of a “midget man” sized weapon. The conceptional art if anything seems to have a less tapered upper stage.
 
Josh_TN said:
sferrin said:
Nik said:
Tangential: The 'Sentinel' design with but one (1) MIRV-type head... Call it the 'Skinny-man' ??
Click to expand...
That's basically what it is. Think Midgetman-light. Will almost certainly be the least capable "ICBM" on the planet it when (if) it ever gets fielded. It'd almost be better to keep MM3.
Click to expand...

Have the requirements or dimensions ever been published? The documentation I’ve read quite explicitly threw out the idea of a “midget man” sized weapon. The conceptional art if anything seems to have a less tapered upper stage.
Click to expand...
There was a pic of either the 1st or 2nd stage being wound at it was TINY for an ICBM. I'd have thought it was more like an ATACMS or Iskander, if that.
 
sferrin said:
Josh_TN said:
sferrin said:
Nik said:
Tangential: The 'Sentinel' design with but one (1) MIRV-type head... Call it the 'Skinny-man' ??
Click to expand...
That's basically what it is. Think Midgetman-light. Will almost certainly be the least capable "ICBM" on the planet it when (if) it ever gets fielded. It'd almost be better to keep MM3.
Click to expand...

Have the requirements or dimensions ever been published? The documentation I’ve read quite explicitly threw out the idea of a “midget man” sized weapon. The conceptional art if anything seems to have a less tapered upper stage.
Click to expand...
There was a pic of either the 1st or 2nd stage being wound at it was TINY for an ICBM. I'd have thought it was more like an ATACMS or Iskander, if that.
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My Twitter connections still believe it will be MMIII size and payload comparable.

If it’s single warhead only in the age of Sarmat and DF-41s I’m gonna be pissed.
 
sferrin said:
That's basically what it is. Think Midgetman-light. Will almost certainly be the least capable "ICBM" on the planet it when (if) it ever gets fielded. It'd almost be better to keep MM3.
Click to expand...
I don't know, if they put a MaRV on it it would have some increased capability but I would have preferred an LGM-118-sized missile that warheads can be added to later after START inevitably gets scrapped.
 
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www.thedrive.com

Firing ICBMs From Lakes, Tunnels Considered Before Air Force Picked New Missile

An Air Force document shows multiple types of missiles, as well as firing them from places other than silos, were all on the table.
www.thedrive.com www.thedrive.com
“…Buying a land-based version of the U.S. Navy's Trident II submarine-launched ballistic missile, a new smaller missile with intercontinental range, or a design based at least in part on an existing commercial space launch rocket, as well as basing them in tunnels or at the bottom of deep lakes were all concepts that were examined….”
 
It appears the USAF has settled on a more or less MM3 sized system. Clearly infrastructure plays a role in this; the existing silos limit missile size for a hot launch. An MX style cold launch would be possible, but assuming that all the silos will be loaded with the new missile that would be a rather massive force given US investment in SLBMs. It’s worth noting the US has over a hundred more launch systems than Russia already even under New START which counts fifty silos as undeployed. China is expanding its neclear force but won’t approach parity until the end of the decade assuming the US doesn’t expand its force, which seems unlikely once New START expires.
 
Josh_TN said:
It’s worth noting the US has over a hundred more launch systems than Russia already even under New START
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It matters what's IN them however. One MM3 with a single warhead does not equate to one SS-18/SARMAT with 10-20.
 
sferrin said:
Josh_TN said:
It’s worth noting the US has over a hundred more launch systems than Russia already even under New START
Click to expand...
It matters what's IN them however. One MM3 with a single warhead does not equate to one SS-18/SARMAT with 10-20.
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Indeed, but the US does have parity warhead wise and a superior ability to upload its weapons precisely because it has more launchers not loaded to capacity. The US could nearly double its deployed warheads.
 
Josh_TN said:
sferrin said:
Josh_TN said:
It’s worth noting the US has over a hundred more launch systems than Russia already even under New START
Click to expand...
It matters what's IN them however. One MM3 with a single warhead does not equate to one SS-18/SARMAT with 10-20.
Click to expand...

Indeed, but the US does have parity warhead wise and a superior ability to upload its weapons precisely because it has more launchers not loaded to capacity. The US could nearly double its deployed warheads.
Click to expand...
With MM3. If GBSD is designed for single-warhead only then that is not a possibility. Also, by uploading MM3s. you lose range. So now you have to task something else to address targets previously handled by MM3. We should have modified all remaining silos for cold-launch. That way, if we wanted to, we could have something as capable as Peacekeeper. Russia already has, and plans to continue so, and China will have shortly (if it doesn't already) in the form of the 10 warhead DF-41. Which is mobile.
 
sferrin said:
Josh_TN said:
sferrin said:
Josh_TN said:
It’s worth noting the US has over a hundred more launch systems than Russia already even under New START
Click to expand...
It matters what's IN them however. One MM3 with a single warhead does not equate to one SS-18/SARMAT with 10-20.
Click to expand...

Indeed, but the US does have parity warhead wise and a superior ability to upload its weapons precisely because it has more launchers not loaded to capacity. The US could nearly double its deployed warheads.
Click to expand...
With MM3. If GBSD is designed for single-warhead only then that is not a possibility. Also, by uploading MM3s. you lose range. So now you have to task something else to address targets previously handled by MM3. We should have modified all remaining silos for cold-launch. That way, if we wanted to, we could have something as capable as Peacekeeper. Russia already has, and plans to continue so, and China will have shortly (if it doesn't already) in the form of the 10 warhead DF-41. Which is mobile.
Click to expand...
I have a hard time believing GBSD will be single warhead only. The paper with the list of options that was linked to above seemed to discount the idea of a "Migetman" type missile. As for range, that isn't really a problem for Russia - I don't think any of the country is more than 5500 miles from say, Minot. Targets in China might be harder to reach with fully loaded MM3s; hopefully GBSD also increases range/throw weight.

As for a cold launch large missile - I think the US was never going to spring for a full sized missile with ten warheads and cold launch in all 450 silos*, and I think the USAF has prioritized using all of those silos as a way of absorbing warhead counts from opposing forces. Most of the US force is and likely will continue to be the SLBMs. A MM3 sized replacement with a bit more accuracy and throw weight seems like an adequate hedge to the SSBNs fleet.


*ETA: I think a very large expensive missile system and silo mod might have threatened the program in Congress.
 
Josh_TN said:
sferrin said:
Josh_TN said:
sferrin said:
Josh_TN said:
It’s worth noting the US has over a hundred more launch systems than Russia already even under New START
Click to expand...
It matters what's IN them however. One MM3 with a single warhead does not equate to one SS-18/SARMAT with 10-20.
Click to expand...

Indeed, but the US does have parity warhead wise and a superior ability to upload its weapons precisely because it has more launchers not loaded to capacity. The US could nearly double its deployed warheads.
Click to expand...
With MM3. If GBSD is designed for single-warhead only then that is not a possibility. Also, by uploading MM3s. you lose range. So now you have to task something else to address targets previously handled by MM3. We should have modified all remaining silos for cold-launch. That way, if we wanted to, we could have something as capable as Peacekeeper. Russia already has, and plans to continue so, and China will have shortly (if it doesn't already) in the form of the 10 warhead DF-41. Which is mobile.
Click to expand...
I have a hard time believing GBSD will be single warhead only. The paper with the list of options that was linked to above seemed to discount the idea of a "Migetman" type missile. As for range, that isn't really a problem for Russia - I don't think any of the country is more than 5500 miles from say, Minot. Targets in China might be harder to reach with fully loaded MM3s; hopefully GBSD also increases range/throw weight.

As for a cold launch large missile - I think the US was never going to spring for a full sized missile with ten warheads and cold launch in all 450 silos*, and I think the USAF has prioritized using all of those silos as a way of absorbing warhead counts from opposing forces. Most of the US force is and likely will continue to be the SLBMs. A MM3 sized replacement with a bit more accuracy and throw weight seems like an adequate hedge to the SSBNs fleet.


*ETA: I think a very large expensive missile system and silo mod might have threatened the program in Congress.
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There's nothing that says you HAVE to put a Peacekeeper in it. Modify the silo for cold-launching a Peacekeeper-sized missile and if you want something smaller stuff a liner in it.
 
Forest Green said:
I would personally design GBSD to carry at least 4 warheads and put 1 in them until New START expires, then 4.
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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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