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

Kat Tsun said:
They're accurate enough to hit targets inside cities without needing MIRVs and high yield enough to destroy them completely with one warhead now. Poseidon and the firecracker W68 warhead was a long time ago.

MIRVs also encourage concentration of missiles and their delivery systems, which is bad in the age of stealth bombers and orbital surveillance, because they can be attacked immediately. You want to distribute these things. Since land-based weapons can't hide underground they have to hide amongst vehicle traffic instead. Finally, they make missiles heavy, and heavy missiles are expensive. They need specialized trucks to move while Midgetman is about at the tail end of the commercial GVWR for the U.S. DOT, which is good, because differentiating between two commercial trailers (according to space based observers) without also making visual identification is hard.

The alternative is that you divest land based weapons and go entirely based on strategic bombers (first strike) and submarines (second strike). I have a pretty good idea of which one of these the USA will actually pick, but if you want to keep a land based missile force you need to make them move and blend in with commercial traffic, or else you simply won't have a land based missile force.
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Do the Russians and Chinese choose to field MIRVs because they are not capable of target accuracy?
 
Kat Tsun said:
They're accurate enough to hit targets inside cities without needing MIRVs and high yield enough to destroy them completely with one warhead now. Poseidon and the firecracker W68 warhead was a long time ago.
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You're confusing Multiple Reentry Vehicles with Multiple Independently-targetable Reentry Vehicles. MRVs all hit the same target, MIRVs can hit multiple targets.

In_A_Dream said:
Do the Russians and Chinese choose to field MIRVs because they are not capable of target accuracy?
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While Russian and Chinese nukes have a larger yield than American warheads, it's been assumed that is because they don't have the same level of accuracy.

But that's not why they've been fielding MIRVs.
 
Kat Tsun said:
They're accurate enough to hit targets inside cities without needing MIRVs and high yield enough to destroy them completely with one warhead now. Poseidon and the firecracker W68 warhead was a long time ago.
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Okay, as it was stated above, you are confusing MRV with MIRV.

The MRV (Multiple Reentry Vehicles) system is essentially a cluster nuclear warheads. After missile is set on trajectory, the warheads detach from upper stage & spread, to cover larger area. They are all aiming for one target, just spreading away to provide better coverage.

The MIRV (Multiple Independently-targetable Reentry Vehicles) system have an additional stage named "bus", which put each single warhead on a trajectory aimed at specific target. Each of MIRV warheads is precisely aimed on separate target alongside missile trajectory path. They aren't all falling on one target (unless such attack is chosen); they are aiming toward individual targets.
 
Here’s a great example of a MRV

The subject of our paper was multiple warhead delivery systems. The title of our paper was “CLAW”, which stood for “Clustered Atomic Warheads”. We delivered this paper at a top secret restricted session of AMRAC at the secure Naval Station in San Diego in 1962. It was the first paper of its type advocating multiple warhead payloads. MIRV hadn’t been invented yet. The capability for Multiple Independently Targeted Re-entry Vehicles didn’t exist in 1962. Our system could deliver multiple warheads, but only on a single target in a circular or elliptical pattern. This was an advance in the state of the art at that time.

[snip]

“Following the success of our AMRAC paper, I was promoted to Project Engineer for the design of a heavy payload system, 39,000 pounds on top of a Titan III missile. The mission was to negate the Leningrad SAM defense system to allow our B 52′s access to the target. My liaison officer was a U.S.A.F. major, who was a B 52 pilot. His idea was that when we softened up the target with our nuclear barrage, he would fly in and finish it off.

“Me and my team designed a three tiered payload with 13 one megaton Mark 11 RV’s in each tier (39 total) which would be spun out in space and impact the Leningrad defenses in three concentric elliptical rings. Our liaison officer was ecstatic, his bomb run would be unopposed. What he didn’t seem to realize was that there would be nothing left to bomb after we laid down a barrage equal to 2000 times the weapon that destroyed Hiroshima.
 
Scott Kenny said:
You're confusing Multiple Reentry Vehicles with Multiple Independently-targetable Reentry Vehicles. MRVs all hit the same target, MIRVs can hit multiple targets.
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Dilandu said:
The MRV (Multiple Reentry Vehicles) system is essentially a cluster nuclear warheads. After missile is set on trajectory, the warheads detach from upper stage & spread, to cover larger area. They are all aiming for one target, just spreading away to provide better coverage.
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bobbymike said:
The subject of our paper was multiple warhead delivery systems. The title of our paper was “CLAW”, which stood for “Clustered Atomic Warheads”. We delivered this paper at a top secret restricted session of AMRAC at the secure Naval Station in San Diego in 1962. It was the first paper of its type advocating multiple warhead payloads. MIRV hadn’t been invented yet. The capability for Multiple Independently Targeted Re-entry Vehicles didn’t exist in 1962. Our system could deliver multiple warheads, but only on a single target in a circular or elliptical pattern. This was an advance in the state of the art at that time.
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The MRV as described by the CLAW concept was implemented on the UGM-27C Polaris A3 using three Mk-2 RVs each caring a 200KT W58 warhead to bracket its' target instead of single 600KT W47Y1 or 1.2MT W47Y2 in a Mk-1 RV.

bobbymike said:
“Me and my team designed a three tiered payload with 13 one megaton Mark 11 RV’s in each tier (39 total) which would be spun out in space and impact the Leningrad defenses in three concentric elliptical rings. Our liaison officer was ecstatic, his bomb run would be unopposed. What he didn’t seem to realize was that there would be nothing left to bomb after we laid down a barrage equal to 2000 times the weapon that destroyed Hiroshima.
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If implemented and WWIII happened not only would Leningrad have been obliterated but also a sizeable chunk of its' surrounding hinterland too.
 
if I'm not mistaken, I believe the current Sentinel design can accommodate a MIRV configuration. Would be interested to see what that looks like if they choose to field it.
 
Absolutely unacceptable. I don’t want to blanket condemn everyone and everything in the MIC/DOD/DC but, sorry, it’s like we’ve given up.

What was the one Minuteman I & II plan, 5000 missiles in silos on trains and mobile launchers in less than a decade?
 
LouderThanBombs2 said:
breakingdefense.com

Sentinel ICBM first flight date now in flux, Air Force says - Breaking Defense

The troubled ICBM program was supposed to fly for the first time in 2026, but now the Air Force says that the date is unknown.
breakingdefense.com breakingdefense.com
It appears that the first flight has been delayed 2 more years to March 2028(Page 80 on the GAO pdf).
Curious what the "critical technology undergoing design changes" is.
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At this point it could be, "we forgot how to make solid propellant". And without a herculean effort, it will only get worse as those who know how to do stuff retire.
 
Sferrin said:
At this point it could be, "we forgot how to make solid propellant".
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Can't be that, we're constantly making Trident IIs in small numbers. And each stage is made differently, so the knowledge of how to make big solid rockets isn't dead.



Sferrin said:
And without a herculean effort, it will only get worse as those who know how to do stuff retire.
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But yes, this part is absolutely true.
 
Sferrin said:
At this point it could be, "we forgot how to make solid propellant". And without a herculean effort, it will only get worse as those who know how to do stuff retire.
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It’s not the rocket motors, it’s the rest of the system, including the launch complex/silo and the avionics. The original plan was to perform the first launches out of a Sentinel spec silo at Vandenberg. With the silo issues, that has obviously had an impact on first flight.
 
Calphor said:
It’s not the rocket motors, it’s the rest of the system, including the launch complex/silo and the avionics. The original plan was to perform the first launches out of a Sentinel spec silo at Vandenberg. With the silo issues, that has obviously had an impact on first flight.
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That's actually worse.
 
I was just looking around on the designation systems website seeing what missile got the "-182" and I found the LGM-142 which turns out to be the LGM-35, so I'm wondering why was the missile given an out of sequence designation?

The "-35" had been previously assigned to the Northrop AQM-35.
 
NMaude said:
I was just looking around on the designation systems website seeing what missile got the "-182" and I found the LGM-142 which turns out to be the LGM-35, so I'm wondering why was the missile given an out of sequence designation?

The "-35" had been previously assigned to the Northrop AQM-35.
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Because the USAF is smoking crack.
 
NMaude said:
I was just looking around on the designation systems website seeing what missile got the "-182" and I found the LGM-142 which turns out to be the LGM-35, so I'm wondering why was the missile given an out of sequence designation?

The "-35" had been previously assigned to the Northrop AQM-35.
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Pure speculation here, but: Titan was LGM-25, and Minuteman is LGM-30. Incrementing by another 5 for the next ICBM almost makes sense.

Provided you ignore the fact that Atlas, Peacekeeper and Midgetman don't fit the putative 'sequence'. Or that it's a fundamentally silly way to apply a designation system. But it's at least an explanation.
 
Yellow Palace said:
Pure speculation here, but: Titan was LGM-25, and Minuteman is LGM-30. Incrementing by another 5 for the next ICBM almost makes sense.

Provided you ignore the fact that Atlas, Peacekeeper and Midgetman don't fit the putative 'sequence'. Or that it's a fundamentally silly way to apply a designation system. But it's at least an explanation.
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Yellow Palace said:
well, it's more sensible than 22, 35, 47.
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By 22 I assume you're referring to the F-22, it is in sequence as the aircraft before it is the Israeli F-21 Kfir and that is preceded by the unfortunately stillborn Northrop F-20 Tigershark.
 
Grey Havoc said:
www.defensenews.com

US Air Force uses leftover ICBM funds to revamp Qatar plane

“This looks like one of the bigger wastes of money inside your budget," Sen. Chris Murphy, D-Conn., said of plans to turn a Qatari jet into Air Force One.
www.defensenews.com www.defensenews.com
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The Air Force plans to use leftover funds from the LGM-35A Sentinel nuclear missile program to help pay for refurbishing a Qatari-donated plane into a new Air Force One presidential transport aircraft.

Air Force Secretary Troy Meink said in a June 26 hearing that the reallocated Sentinel money was “excess to need in [20]24,” and stressed the program to build new intercontinental ballistic missiles and launching infrastructure would not suffer or see further delays from moving funds around.

“Let me be very clear, the Sentinel program is fully funded [and has] all the resources it needs to execute as quickly as possible,” Meink told the Senate Appropriations defense subcommittee.
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Why do I think this is a classic case of 'Famous last words'?
 
The legislation authorizes $848.2 billion for the military, including at least $211.3 billion for the Air Force and Space Force. It looks to save the Air Force’s plan to buy two E-7 Wedgetail airborne target-tracking jet prototypes from cancellation, block retirement of the A-10 Thunderbolt II attack planes, and boost funding for the new Sentinel ground-based nuclear missiles to over $3 billion, among myriad other spending tweaks and oversight provisions.
 
Grey Havoc said:
Why do I think this is a classic case of 'Famous last words'?
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A former coworker of mine was working for a supplier on the Commanche program. Colonel came around for a dog and pony show, telling them how awesome the Commanche was going to be for the US Army. Less than a week later it was cancelled.

And how can they possibly have, "leftover funds"? If nothing else, use it to buy long-lead items for future production.
 
GeorgeA said:
2027-28 per the article.
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Since the first-stage has already been tested twice they could do an earlier test-flight using just a live first-stage with inert second and third stages using a simple autopilot to control the stack following a simple pitch-and-roll programme.
 
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NMaude said:
Since the first-stage has already been tested twice they could an earlier test-flight using just a live first-stage with inert second and third stages using a simple autopilot to control stack following a simple pitch-and-roll programme.
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I wouldn't be surprised if the first test is that exactly.
 
NMaude said:
Since the first-stage has already been tested twice they could do an earlier test-flight using just a live first-stage with inert second and third stages using a simple autopilot to control the stack following a simple pitch-and-roll programme.
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By this logic, you might as well include a live second stage since they have tested two of those as well.
 
Calphor said:
By this logic, you might as well include a live second stage since they have tested two of those as well.
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There is all-up testing, yes, but on the other hand if the test-programme is being a bit more conservative in their testing then that would be the approach used.
 
Didn’t see this sorry if it’s a repost

theaviationist.com

Sentinel ICBM Likely to Require New Silos, Pushing Costs Even Higher

The troubled LGM-35 Sentinel ICBM program hit another hurdle as new assessments reveal a previous plan to re-use LGM-30 Minuteman III missile silos may
theaviationist.com theaviationist.com

“It will be larger, though lighter, than the Minuteman, owing to modern construction materials and techniques. Each missile, under current nuclear doctrine, will carry just one nuclear warhead, although the missile’s payload capacity would almost certainly allow for this number to be increased if policies changed. Additionally, the extra capacity can be used to carry decoy payloads to either passively or actively disrupt hostile interception efforts.”
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That should allow more than three RVs?
 
bobbymike said:
Didn’t see this sorry if it’s a repost

theaviationist.com

Sentinel ICBM Likely to Require New Silos, Pushing Costs Even Higher

The troubled LGM-35 Sentinel ICBM program hit another hurdle as new assessments reveal a previous plan to re-use LGM-30 Minuteman III missile silos may
theaviationist.com theaviationist.com

“It will be larger, though lighter, than the Minuteman, owing to modern construction materials and techniques. Each missile, under current nuclear doctrine, will carry just one nuclear warhead, although the missile’s payload capacity would almost certainly allow for this number to be increased if policies changed. Additionally, the extra capacity can be used to carry decoy payloads to either passively or actively disrupt hostile interception efforts.”
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That should allow more than three RVs?
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I'm expecting that it's either 1x RV plus penaids or 3x RVs

Unless someone decides to turn Sentinel into Trident.
 

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