AGM-158 JASSM

All the JASSM variants are AGM-158. The C model is the LRASM.
 
Moose said:
All the JASSM variants are AGM-158. The C model is the LRASM.
That's correct. The LRASM is very similar to the JAASM (AGM-158A) and JASM-ER (AGM-158B). -SP
 
Steve Pace said:
Moose said:
All the JASSM variants are AGM-158. The C model is the LRASM.
That's correct. The LRASM is very similar to the JAASM (AGM-58A) and JASM-ER (AGM-58B). -SP

Except you didn't say "LRASM". Was wondering what this 3rd variant of "JASSM" was.

Moose said:
All the JASSM variants are AGM-158. The C model is the LRASM.

Not surprising other than I didn't think LRASM was considered mature enough to get an official designation. It's still a DARPA program after all.
 
sferrin said:
Steve Pace said:
Moose said:
All the JASSM variants are AGM-158. The C model is the LRASM.
That's correct. The LRASM is very similar to the JAASM (AGM-58A) and JASM-ER (AGM-58B). -SP

Except you didn't say "LRASM". Was wondering what this 3rd variant of "JASSM" was.
Excusemwaaaaah... I don't claim to be perfect. -SP
 
Steve Pace said:
sferrin said:
Steve Pace said:
Moose said:
All the JASSM variants are AGM-158. The C model is the LRASM.
That's correct. The LRASM is very similar to the JAASM (AGM-58A) and JASM-ER (AGM-58B). -SP

Except you didn't say "LRASM". Was wondering what this 3rd variant of "JASSM" was.
Excusemwaaaaah... I don't claim to be perfect. -SP

Yeah, it was probably nit-picking. (I was pretty sure what you meant but you never know. Maybe it was some other variant revealed or something.)
 
sferrin said:
Steve Pace said:
sferrin said:
Steve Pace said:
Moose said:
All the JASSM variants are AGM-158. The C model is the LRASM.
That's correct. The LRASM is very similar to the JAASM (AGM-58A) and JASM-ER (AGM-58B). -SP

Except you didn't say "LRASM". Was wondering what this 3rd variant of "JASSM" was.
Excusemwaaaaah... I don't claim to be perfect. -SP

Yeah, it was probably nit-picking. (I was pretty sure what you meant but you never know. Maybe it was some other variant revealed or something.)
Here's the release in part from USN site:
Contacted by Navy Recognition, a Lockheed Martin spokesperson said "we learned over the weekend that LRASM's official designation will be AGM-158C". AGM-158C is the designation for the air-launched LRASM missile only. There is no surface-launch LRASM program of record yet. The Department of the Navy, Naval Air Warfare Center, gave the official designation.
 
Question that came up in the CSIS Taiwan study: does AGM-158B have any capability against moving ships? I was inclined to say "no", but they seem to assign it some kind of conditional ability to do so. IMO, their reasoning is extremely thin:

"The variables of study must therefore both be uncertain and likely to have a high impact on the outcome. For example, in this project it became clear that the effectiveness of the Joint Air-to-Surface Standoff Missile (JASSM) against moving ships was a critical factor in the outcome of the game after playing several iterations. A close review of the literature showed that this effectiveness was unclear. The project team therefore decided that the effectiveness of the JASSM was an important variable to test."

"Publicly available information about the capabilities of the JASSM-ER is unclear. There are hints that
it could have some anti-ship capability. In its FY 2022 budget request, the Navy introduced the AGM158B JASSM-ER to “enhance long range strike and existing OASuW [offensive anti-surface warfare] capability.”226 The document suggests that it will be possible to “convert JASSM-ER software to a C++ software baseline, similar to LRASM, and focus on combining JASSM-ER strike capability and LRASM
OASuW capability into a merged Navy JASSM baseline. Future efforts will expand both Navy strike and OASuW capabilities within Navy JASSM.”227 The Air Force also continues to upgrade variants of the JASSM-ER. Depending on the adjustments required to make the missile capable of anti-ship operations, it is possible that the capability could be retrofitted onto existing systems. "

 
If JASSM could hit moving ships they wouldn't need LRASM. Also, I thought LRASM got a bunch of ESM gear/antenna to help it avoid defenses.
 
If JASSM could hit moving ships they wouldn't need LRASM. Also, I thought LRASM got a bunch of ESM gear/antenna to help it avoid defenses.

I assume their argument is that the IIR seeker can be used to acquire a ship type target the same as a building or land target, so long as it’s close enough and the target drift and angle viewpoint changes don’t throw the seeker off. I don’t know how reasonable of an assumption that is - does LRASM use the same IIR seeker as the rest of JASSM family or is it customized?

LRASM still has the advantage of passive RF target detection, identification, and geo location/guidance. The same ability likely allows it to avoid air defense threats, assuming the threat emitter isn’t on its target list. If the AGM-158B seeker could be programmed to engage a ship target, then the only problem would be accurately placing the targets inside its seeker envelope. So precise location, course, and speed of target are necessary, plus large course changes by the target at high speed during flight time might evade. LRASM wouldn’t have those limitations against an emitting target that it was capable of receiving (no idea what frequency range or other limitations of LRASMs RF receivers might be).

AGM-158B as a ship killer would still be extremely significant given the inventory and number of launch platforms. It would also explain the incredibly small LRASM buys by both services.
 
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Circling back to this, it looks like JASSM was going to have a datalink going back quite some time that would allow for retargeting or target updates in flight. This article explicitly states that maritime targets were a goal:

"The datalink flight trials are a key element of plans to field a maritime-mode version of JASSM in 2010-11. Lockheed and the US Air Force are discussing the formal launch of a JASSM maritime interdiction advanced concept technology demonstration to start in 2007, with full-scale development activities to follow from late 2008. Lockheed says it demonstrated an initial maritime strike capability last April using a Block II Lot 3 missile with GPS guidance to attack a barge anchored in the Gulf of Mexico."


It isn't clear if the L3 datalink was added to AGM-158B though.

EDIT: it appears that the datalink is one way only back to the firing platform for BDA, but that the B2/D variants will be retargetable in flight:

"The current weapons sport a one-way datalink, but it seems like the AGM-158B-2 will feature the updated two-way WDL of the AGM-158D JASSM-ER (the missile formerly known as JASSM-XR)."



What it does seem to be able to do is recognize targets from different approach angles, as it apparently stores a 3D model of the target:

"The missile is guided by INS/GPS unit developed for the JDAM and JSOW bombs, and also a IR seeker for terminal guidance. It also incorporates three-dimensional targeting models of the intended targets, of which eight can be stored in each missile."

 
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What I'd like to know is how does the missile control its pitch and roll axes? It clearly has a moveable tail fin yet where you'd expect the elevators to be there are what appear to be fixed tabs.
 
What I'd like to know is how does the missile control its pitch and roll axes? It clearly has a moveable tail fin yet where you'd expect the elevators to be there are what appear to be fixed tabs.

There are ailerons in the wings. I suspect they have pitch authority as well if they are deflected together rather than opposite for roll.
 
What I'd like to know is how does the missile control its pitch and roll axes? It clearly has a moveable tail fin yet where you'd expect the elevators to be there are what appear to be fixed tabs.

There are ailerons in the wings. I suspect they have pitch authority as well if they are deflected together rather than opposite for roll.
Missiles like JASSM, Regulus, Snark, etc have always baffled me. Presumably they act similar to delta-wings but with a different planform?
 
What I'd like to know is how does the missile control its pitch and roll axes? It clearly has a moveable tail fin yet where you'd expect the elevators to be there are what appear to be fixed tabs.
JASSM uses "elevons", combine elevator + aileron

A lot of details of the JASSM can be found here :

 
As a taxpayer it blows my mind / infuriates me that this stuff is out there.
 
As a taxpayer it blows my mind / infuriates me that this stuff is out there.

It's basically a consequence of the absolutely shitty service intranets. People don't have anywhere to store the docs they need access to for their promotion exams, so they throw it up on Scribd, etc. Add the fact that this stuff is not properly marked -- at bare minimum, this doc should be For Official Use Only.
 
The question that needs to be asked does the JASSM manual have any confidential, secret or top-secret material in it?
 
So AGM-158D will use a satellite datalink, a revised wing arrangement for more range, and M code? Is it to have the new external coating as well? Was a range figure released?
 
The question that needs to be asked does the JASSM manual have any confidential, secret or top-secret material in it?
Not one that matters here, but in general the stuff we are interested in, assuming it was classified at all, would likely be the lowest classifications. The higher the classification, the more into the weeds about something you get. I remember one worksheet that was C, but TS when filled in.
 
Any idea what is the NiMH & Li-Ion battery for? This is the first time I see such batteries mentioned for missile use.
To power the seeker I imagine and possibly a Tx for communicating back to base or maybe an ECM unit of some kind. Don't know why it needs a Nickel Metal Hydride battery though, that's generally used for rechargeable applications, which would seem kind of pointless here. The way it uses the terms JASSM-ER and AGM-158D separately is also kind of confusing. They're the same missile AFAIK.
 
Any idea what is the NiMH & Li-Ion battery for? This is the first time I see such batteries mentioned for missile use.
To power the seeker I imagine and possibly a Tx for communicating back to base or maybe an ECM unit of some kind. Don't know why it needs a Nickel Metal Hydride battery though, that's generally used for rechargeable applications, which would seem kind of pointless here. The way it uses the terms JASSM-ER and AGM-158D separately is also kind of confusing. They're the same missile AFAIK.
If you end up not firing the missile you'd want to be able to recharge your batteries instead of replacing them.
 
AGM-158B = JASSM ER

After that the nomenclature gets confusing. I’ve heard the terms AGM-158B2/B3/C3/D and JASSM XR thrown around with various new features like wing alteration, weapon datalink, new coating, and large range increase said to be the changes but with no clear map between those two sets and no indication what is coming off the line when.
 
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AGM-158B = JASSM ER

After that the nomenclature gets confusing. I’ve heard the terms AGM-158B2/B3/C3/D and JASSM XR thrown around with various new features like wing alteration, weapon datalink, new coating, and large range increase said to be the changes but with no clear map between those two sets and no indication what is coming off the line when.
I meant to say that the AGM-158D is the JASSM-XR AFAIK, at least according to wiki. That seems to have been renamed AGM-158B-2 now though. Who the hell numbers these things? Seems it was renamed twice:


In March 2016, Lockheed Martin began analysis on an enhanced wing design to further increase range.[53] In September 2018, the corporation was awarded a contract to develop an "Extreme Range" variant of the AGM-158. The weapon would weigh about 5,000 lb (2,300 kg) and deliver a 2,000 lb (910 kg) warhead out to a range of 1,900 km (1,200 mi; 1,000 nmi).[54][55] Originally called the JASSM-XR and later designated the AGM-158D, it features a new missile control unit, changes to the wings, a different paint coating, an Electronic Safe and Arm Fuze, secure GPS receiver, and program protection requirements at a unit cost of $1.5 million. Low-rate initial production began in 2021 as part of Lot 19 with deliveries beginning in January 2024 at a rate of five per month for the first 40 missiles.[56] The designation was later changed again to the AGM-158B-2.[57][58]
 
I meant to say that the AGM-158D is the JASSM-XR AFAIK, at least according to wiki. That seems to have been renamed AGM-158B-2 now though. Who the hell numbers these things? Seems it was renamed twice:

There was a rumor that the "XR" was going to be a version with extremely long range extension - like, Tomahawk range. Some accounts of this indicated it was going to involve a stretch of the airframe (presumably becoming more AGM-86 sized). I haven't heard any mention of this ever since. The other way you might get that range extension is by cutting the warhead in half - you could use the AGM-84H as an off the shelf solution (EDIT: actually WDU-40 isn’t much lighter; maybe JSMs warhead). But again, not heard anything about this in a couple years.

I've seen mentions of the other changes fairly frequently and seen them variously associated with the other letter designations - B2 (range extension?), B3 (two way datalink added?), C3 (whatever the hell the USN is buying...2 way datalink but sans the RF seeker of the "real" LRASM), and D (all of the previous changes plus a new external coating?). Somewhere in there you can throw in the M code upgrade as well; I've no idea where. But in all cases I've seen exactly one document that mentions the change and the designation and in some cases they contradict each other, so no idea. It does seem to be the case that regular production line items will get the weapon datalink and M code update in the next couple years (or rather prep for receiving M code, as GPSIII's ground segment seems to have been a shit show).

The million dollar question for me would be which versions of the weapon have any capability, even a limited one, against ship targets. I found a news clip that mentioned a 2way datalink being tested back in 2012 and implying this was all that was necessary. That might have just been the LRASM. But again, who knows: it almost seems like the USAF is deliberately muddying the waters at this point.
 
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When I worked at Williams, there was a lot of chatter about the JASSM XR using an uprated F107 variant. That being said, the missile is likely is using a smaller more efficient warhead to make room for more fuel.
 
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There was a rumor that the "XR" was going to be a version with extremely long range extension - like, Tomahawk range. Some accounts of this indicated it was going to involve a stretch of the airframe (presumably becoming more AGM-86 sized). I haven't heard any mention of this ever since. The other way you might get that range extension is by cutting the warhead in half - you could use the AGM-84H as an off the shelf solution (EDIT: actually WDU-40 isn’t much lighter; maybe JSMs warhead). But again, not heard anything about this in a couple years.

I've seen mentions of the other changes fairly frequently and seen them variously associated with the other letter designations - B2 (range extension?), B3 (two way datalink added?), C3 (whatever the hell the USN is buying...2 way datalink but sans the RF seeker of the "real" LRASM), and D (all of the previous changes plus a new external coating?). Somewhere in there you can throw in the M code upgrade as well; I've no idea where. But in all cases I've seen exactly one document that mentions the change and the designation and in some cases they contradict each other, so no idea. It does seem to be the case that regular production line items will get the weapon datalink and M code update in the next couple years (or rather prep for receiving M code, as GPSIII's ground segment seems to have been a shit show).

The million dollar question for me would be which versions of the weapon have any capability, even a limited one, against ship targets. I found a news clip that mentioned a 2way datalink being tested back in 2012 and implying this was all that was necessary. That might have just been the LRASM. But again, who knows: it almost seems like the USAF is deliberately muddying the waters at this point.
Yes, I understood JASSM-XR to be the AGM-86 CALCM replacement, with a separate LRSO missile for the nuclear option.
 
Found this doc:


There's a table inside of it that has a line item "LRASM-ER (AGM-158C-3)"

Wasn't there a budget doc that described the 158C3 as ditching the RF guidance system but retaining the other features? I seem to recall something to that effect. If so, it seems the reason that is being undertaken is not to save money or even increase productivity - it is to increase endurance. Purchase numbers are still anemic though.

The AGM-158C1 (what I guess you would call the baseline) is projected to be purchased at a hundred a year for five years - still seems awfully low.
 
Found this doc:


There's a table inside of it that has a line item "LRASM-ER (AGM-158C-3)"

Wasn't there a budget doc that described the 158C3 as ditching the RF guidance system but retaining the other features? I seem to recall something to that effect. If so, it seems the reason that is being undertaken is not to save money or even increase productivity - it is to increase endurance. Purchase numbers are still anemic though.

The AGM-158C1 (what I guess you would call the baseline) is projected to be purchased at a hundred a year for five years - still seems awfully low.
AGM-158C-2 has been described as a Navy JASSM, with parts related to LRASM but no RF seeker.


Seems like C-3 is probably an extended-range version with the RF seeker (hence LRASM, not JASSM)
 
AGM-158C-2 has been described as a Navy JASSM, with parts related to LRASM but no RF seeker.


Seems like C-3 is probably an extended-range version with the RF seeker (hence LRASM, not JASSM)

Thanks. I cannot keep up with the AGM-158 designations. So it *seems* like C3 is probably an effort to miniaturize electronics and add on any changes to the B3 model that extend range, where as C2 just deletes equipment to gain range as a short term solution.
 

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