Speed and Low-Observability trade-off on ASM survivability and lethality

[Maro.Kyo]

On last year's Naval News article about POLARIS 21, I've been intrigued about certain assessments of the MN as a result of the exercise. One of which was as follows :

“The cooperation with the British has so far been hampered by divergent military-technical analyses and industrial interests. Simulations carried out by the Navy and the DGA in the field of anti-surface warfare show that stealth, so much vaunted by the British, cannot by itself make a real difference in naval combat. The stealthy anti-ship missile is indeed detectable as soon as it passes the horizon, even low over the water. High speed and maneuverability, on the other hand, are far more credible factors for operational superiority and lethality.”

Feedback on French Navy High Intensity Exercise POLARIS - Naval News

Review of the French Navy (Marine Nationale)'s feedback on the high-intensity exercise 'POLARIS' conducted from November 18 to December 3, 2021.

www.navalnews.com

Which got me very interested as this seemed to be completely opposite of what the other navies around the world have decided for. For instance DARPA have abandoned LRASM-B in favor of the -A earlier in the program. Even more recently the NGSC was envisioned as a LO subsonic stand-off munition(s). Norwegians went with a stealthy NSM which is a popular choice nowadays and the Japanese are developing two new long-range, stealthy anti-surface missiles despite the improved ASM-3 and the development of Hypersonic ASM/land-attack cruise missile dubbed the "Hypersonic Missile". Also according to the Swedish FOI I've seen elsewhere, they also seems to put heavier emphasis on low-observability than outright speed. On this regard, the French assessment seems to be more akin to the Russian approach to the ASM than the Western one.

I wonder which threat assessment and simulated scenario the MN and DGA used that have led to such conclusions they came up with. Maybe some French members (@Archibald @Deltafan and others) of the forum have some background information behind such assessment? More than anything, it is true that, given both the subsonic and supersonic munitions sea skim at a very low altitude these days and that the fleet defence ships are equipped with very long range, precise and high rate of scan radars, by the time an ASM reaches the radar horizon of an air defence ship (usually ~40km), it is almost a given that the air-defence ship will be able to detect it. Though, obviously there's a whole different picture to be considered when NCW capabilities and airborne surveillance and fire control comes into picture. I suspect that the MN and DGA didn't anticipate a hostile threat with OTH detection and fire control capability like the E-2 and CEC. Apart from that, I think the French are quite assured that a naval integrated surveillance and fire-control capabilities could deter any sub-sonic LO threats since they are developing and implementing VCN already.

On the other hand, the following article makes it seems like such arguments might be stemming from program work-share concerns. Well it's a question of if the chicken comes first or an egg, as in if such French assessment stems from the work-share problem or the work-share problem stems from different assessments. I wasn't able to find an answer on that matter as well.

This decision is regarding a new propulsion solution for a “subsonic, low observable missile” which is said to be the favored option of the Royal Navy. The French Navy is said to be in favor of a ramjet-powered, supersonic anti-ship missile with “high penetration capacity”. According to our information, MBDA along with UK’s DE&S and France’s DGA are still working on both missile concepts (subsonic and supersonic). A source with knowledge of the matter told Naval News that the FC/ASW program is currently in a 36 months-long assessment phase. The program is set to reach a so-called “decision point” next summer (2023). In all likelihood, MBDA and both the UK and France will continue to develop and eventually produce both type of missiles because they are complementary. The subsonic missile will feature a majority of British content but its propulsion will be Franco-British. Likewise the supersonic missile will be French for the most part but will feature some British content, especially in its seeker.

Rolls-Royce and Safran Team Up for FC/ASW Next Gen Missile - Naval News

Rolls-Royce and Safran Power Units have jointly signed an Assessment Phase contract with MBDA, as part of the Franco-British Future Cruise / Anti-Ship Weapon (FC/ASW) programme.

www.navalnews.com

 

[Maro.Kyo]

Similar discussion has been there a few years ago on the forum as well, but a definitive superiority of one aspect compared to the other was not determined.

Further material of interest in AsHM design.

Naval Engineers Journal Volume 109 Issue 1 1997 J. F. McEachron - Subsonic and Supersonic Antiship Missiles - An Effectiveness and Utility Comparison | PDF | Surface To Air Missile | Mach Number

Naval Engineers Journal. This edition describes design and measure of effectiveness of subsonic and supersonic anti ship missiles. More or less this describes the US approach toward anti ship missiles .

www.scribd.com

So basically if one wish for small AsHM with standoff distance and difficult to detect, subsonic options seems to be technically more appealing. If one wish for AsHM that difficult to engage with missile or CIWS gun and no size constraints plus engaging Time critical fast target..Supersonic and hypersonic approach got the merit.

 

[red admiral]

On the other hand, the following article makes it seems like such arguments might be stemming from program work-share concerns. Well it's a question of if the chicken comes first or an egg, as in if such French assessment stems from the work-share problem or the work-share problem stems from different assessments.

It does seem odd that unspecified French assessments lead to the solution favoured by MBDA France, to the contrary of every other programme

 

[TomS]

On the other hand, the following article makes it seems like such arguments might be stemming from program work-share concerns. Well it's a question of if the chicken comes first or an egg, as in if such French assessment stems from the work-share problem or the work-share problem stems from different assessments.

It does seem odd that unspecified French assessments lead to the solution favoured by MBDA France, to the contrary of every other programme

I was going to point out that the NEJ article favoring stealthy subsonic missiles came from an McDonnell Douglas engineer working on JASSM.

Also, I have an earlier copy of that paper, dated December 1994, apparently circulated by McDonnell Douglas directly and approved for release by what was then the Program Executive Office for Cruise Missiles and Unmanned Aerial Vehicles (PEO [CU]). Text appears to be almost identical, aside from a couple of tweaks to remove the company name from the NEJ text. It would be interesting to see what motivated this release -- I can't think of a program for a supersonic AShM in this timeframe. Maybe the MA-31 targets?

 

[red admiral]

It would be interesting to see what motivated this release -- I can't think of a program for a supersonic AShM in this timeframe. Maybe the MA-31 targets?

ASALM / SLAT follow on pitch from MM?

 

[TomS]

It would be interesting to see what motivated this release -- I can't think of a program for a supersonic AShM in this timeframe. Maybe the MA-31 targets?

ASALM / SLAT follow on pitch from MM?

The timing seems off. MM definitely pitched ASALM/SLAT as an AShM in the late 1980s (Friedman mentions this in his 1989 Naval Weapons Systems as a 1987 proposal called Harpoon II) but by the early 1990s, SLAT was an absolute train wreck and no one was talking about anything but better versions of Harpoon. ANS was falling apart at the same time. This feels like a shot against a weapon system that was already a non-starter for the West, if only from a budget perspective.

Possibly it was just intended as a reassurance that Harpoon was "good enough" and should continue.

 

[H_K]

It does seem odd that unspecified French assessments lead to the solution favoured by MBDA France, to the contrary of every other programme

Might be worth expanding your horizons beyond the borders of US & Europe because “every other programme” elsewhere most definitely favors supersonic anti-ship missiles.

South Korea, Japan, Taiwan, India, China, Russia are all going supersonic.

In fact the French & Germans had their own supersonic ASM program in the 80s/90s, which was only abandoned for financial reasons post-Cold War. Seems like the US, UK and Norwegians are the odd ones out on this one.

 

[timmymagic]

It does seem odd that unspecified French assessments lead to the solution favoured by MBDA France, to the contrary of every other programme

Might be worth expanding your horizons beyond the borders of US & Europe because “every other programme” elsewhere most definitely favors supersonic anti-ship missiles.

South Korea, Japan, Taiwan, India, China, Russia are all going supersonic.

In fact the French & Germans had their own supersonic ASM program in the 80s/90s, which was only abandoned for financial reasons post-Cold War. Seems like the US, UK and Swedes are the odd ones out on this one.

I think you've stumbled on the real reason for the French direction of travel....

FCASW is/was supposed to be a single munition that covers a lot of bases. Storm Shadow/SCALP EG replacement from combat aircraft and Exocet/Harpoon replacement.

The Storm Shadow/SCALP EG angle clearly requires a long ranged, subsonic, stealthy munition...hence the UK's insistence on that type of weapon....and I rather suspect the Armee de l'Air would agree if left to its own devices...

Meanwhile MBDA France's biggest seller of the last few decades, Exocet, is currently doing very little business....some nations are developing their own weapons.....others have purchased more modern weapons like Gabriel V, RBS15 mk3 and 4....but in general NSM is sweeping the board when it comes to Anti-Ship missile sales (a subsonic, stealthy weapon no less), with a new customer announced seemingly every week....with LRASM lurking for those with really big appetites, Mk.41 VLS and budgets to match......and all the while MBDA France is watching its future revenues vanishing in front of its eyes...

If you look at MBDA France's product line up, the future isn't looking great....

1. Exocet - Practically unsaleable now...
2. MdCN - Hugely expensive, no-one but France will buy it...limited production run
3. Aster -Fairly niche, very expensive and anyone who is going to buy it has...there will be some upgrade works to get on with and new variants but its not going to suddenly sell to lots of countries...or in large quantities.
4. Akeron - Akeron MP formerly called MMP. Hasn't exactly set the world alight...no doubt its a good missile (I wish the UK would buy it personally) but in 5 years its managed to get into service with 1 user...France (with Sweden on the way). Even the Ukraine war hasn't spurred sales with France missing the opportunity to send some over...meanwhile Javelin with its new LWCLU is racking up sales...and Spike has most of the European market cornered. Akeron LP has yet to exist and could be good, but will be trying to get established in a market dominated by Hellfire....and will be integrated on Tiger....a dying platform, one of whose users (if they remain) has their own MBDA missile (Germany), the other user (Spain) uses the Spike-LR.
5. MICA - Has actually sold well in terms of numbers of users over the years. But tends to sell to countries who are excluded from other weapons and who don't purchase vast numbers. Will need a costly upgrade to remain competitive however...and will suffer from increased competition from CAMM, Barak 8, Spyder etc. Won't get integrated on the majority of air platforms either in the future...Mirage 2000 is on the way out as well...
6. SmartGlider - Has appeared at lots of trade shows but has yet to enter the real world....by the time it arrives SDB2 and Spear will have the market pretty much sewn up. Doesn't really offer much in comparison to be honest...won't be integrated on most platforms, so the market is very limited.
7. Mistral - Will continue to do similar business as MICA, slow and steady in comparatively small numbers. Has had a recent upgrade so should see some sales post-Ukraine. Again, however, its a crowded market place these days....with around 30 countries making MANPADS..
8. Meteor - Bit part player...very small share of the operation
9. Sea Venom - Will sell, but they're not the lead and will never do huge sales
10. BANG - No....tiny sales. Everyone will continue to buy Paveway, SDB1 or JDAM variants...

The French missile industry has traditionally been strong in sales in 3 areas...

1. Anti-shipping (Exocet the big seller)
2. Anti-Armour (SS11, MILAN and HOT)
3. Surface to Air (Crotale, Roland)

As of now, the future for 2 of those segments looks pretty bleak....with anti-air potentially ticking along, but not really setting the world alight...

I suspect the desire for a very sexy supersonic missile is to try and fill the gap that Exocet is leaving. Customers smart enough to buy subsonic, stealthy anti-ship missiles have already made their move for the next 30+years...but there is still a market for those who could be seduced by speed...(side look at the Middle East...)

Meanwhile the UK, despite having 7 different varieties of heavyweight anti ship missiles over the years (Martel, Ship launched Exocet, Ground launched Exocet, Ship launched Harpoon, Sub launched Harpoon, Air launched Harpoon and Sea Eagle), has never actually managed to fire one in combat and has recently chosen NSM for its surface fleet....so is rather more concerned about replacing a missile it (and the French) have actually used in combat on several occasions (Storm Shadow)....for long ranged land attack...if it gets a real heavyweight anti-ship missile out of it its a side benefit. If it gets a replacement for Tomahawk and a sub launched version even better...

The problem with the French position is that a medium ranged supersonic missile can clearly not replace Storm Shadow. Either for the UK or France. It's increasingly looking like they've wanted 2 missile types from day 1 with the hope the UK co-funds their Exocet replacement....hopefully the UK negotiators have realised this and use it to their advantage...

 

[H_K]

FCASW is/was supposed to be a single munition that covers a lot of bases. Storm Shadow/SCALP EG replacement from combat aircraft and Exocet/Harpoon replacement.

No. FCASW always left the door open for 2 different vectors. That was the whole point of the concept study phase, to evaluate whether the 2 requirements were best served by one weapon or a family of weapons or 2 distinct weapons with some commonality. But the requirement clearly spelled out 2 separate capabilities for a reason (FASW - Future Anti Ship Weapon and FCM - Future Cruise Missile).

NSM is sweeping the board when it comes to Anti-Ship missile sales (a subsonic, stealthy weapon no less)
If you look at MBDA France's product line up, the future isn't looking great....

1. Exocet - Practically unsaleable now

Not really. Exocet while long in the tooth is still selling nicely to its established user base. That goes beyond just French-built ships as Damen, Fincantieri, TKMS, Navantia etc have all exported a lot more ships in recent years with Exocet than NSM (e.g. Meko A200 for Egypt, Sigma 10514 for Indonesia & Columbia, Avante 2200 for Saudi Arabia, Falaj class for UAE, Doha class for Qatar...).

What NSM has going for it is a lock on the Harpoon replacement market for the big NATO navies. That still leaves space for Exocet as the #2 solution in the global market (far ahead of others like Gabriel V, RBS-15 Mk4, Teseo EVO etc) and probably still #1 for export markets outside the West.

Likewise Mica is still outselling CAAM/Asraam in ground, naval and air launched applications, having been recently modernised. So MBDA FR has a healthy business for the foreseeable future.

 

[Maro.Kyo]

FCASW is/was supposed to be a single munition that covers a lot of bases. Storm Shadow/SCALP EG replacement from combat aircraft and Exocet/Harpoon replacement.

The Storm Shadow/SCALP EG angle clearly requires a long ranged, subsonic, stealthy munition...hence the UK's insistence on that type of weapon....and I rather suspect the Armee de l'Air would agree if left to its own devices...

Meanwhile the UK, despite having 7 different varieties of heavyweight anti ship missiles over the years (Martel, Ship launched Exocet, Ground launched Exocet, Ship launched Harpoon, Sub launched Harpoon, Air launched Harpoon and Sea Eagle), has never actually managed to fire one in combat and has recently chosen NSM for its surface fleet....so is rather more concerned about replacing a missile it (and the French) have actually used in combat on several occasions (Storm Shadow)....for long ranged land attack...if it gets a real heavyweight anti-ship missile out of it its a side benefit. If it gets a replacement for Tomahawk and a sub launched version even better...

The article seems to make it sound like the Briitish assessment doesn't only account for Shadow/SCALP replacement but a general ASuW applications against ships and I don't think the way you see it is really representative of the whole picture. There clearly seems to be a different approach to ASuW (anti-ship) between the two countries.

To reiterate, my question and the whole purpose of this thread is to answer : "Why the French thinks that stealth alone doesn't suffice for ASM lethality/survivability? Why does the British (and the US and the Norwegians) think otherwise?".

 

[Maro.Kyo]

Might be worth expanding your horizons beyond the borders of US & Europe because “every other programme” elsewhere most definitely favors supersonic anti-ship missiles.

South Korea, Japan, Taiwan, India, China, Russia are all going supersonic.

In fact the French & Germans had their own supersonic ASM program in the 80s/90s, which was only abandoned for financial reasons post-Cold War. Seems like the US, UK and Norwegians are the odd ones out on this one.

Like I've said, Japan is developing two new stealth ASM despite the predating ASM-3 and its improved variants under development as well as a hypersonic ASM/land attack cruise missile.

Korea is also considering an ASM variant of a LRAGM-II which is also a stealth munition and they still haven't decided on how to replace their primary workhorse ASM, the C-STAR.

Taiwan is operating HF-2 and -3 simultaneously.

Besides, one thing I know about the LRASM is that it requires a vast and deep supporting database from ESMs for it to be able to operate efficiently at its intended range; basically relies on a database only the US could accumulate and construct. Stelath ASMs generally requires EMCON which means terminal phase target acquisition is always a headache and maybe the Eastern Bloc doctrine sees it as an unnecessary hurdle/stealth not as worth in exchange to accurate target acquisition. France might be agreeing with such views as well.

 

[Josh_TN]

I think different countries using different firing platforms against different levels of defense drives different solutions. As the post from a previous thread quoted above noted, subsonic is going to favor smaller weapons that can get by with a simple turbojet. Ships with dedicated AShM tubes (say, Slava) or bomber sized aircraft can use large supersonic weapons. A key point someone else brought up is whether you are firing at a defense system with airborne radar coverage or not. Sans any OTH sensors, a supersonic weapon can close with a surface target at low altitude and stealth is pointless. Against targets under an AWACs platform, a low RCS makes a lot more sense. I'd say the trend now amongst countries is the mix and match flight profiles; anyone who can afford to has both types.

 

[Maro.Kyo]

Sans any OTH sensors, a supersonic weapon can close with a surface target at low altitude and stealth is pointless. Against targets under an AWACs platform, a low RCS makes a lot more sense. I'd say the trend now amongst countries is the mix and match flight profiles; anyone who can afford to has both types.

Which is the reason I'm curious of which situation the DGA has employed for simulation and assessment. If their simulated thread was the
Chinese navy, it would be very wrong to assume that they wouldn't be able to possess OTH search and track capabilities as well as integrated surveillance and fire control capabilities since a.) they already have their E-2 equivalents and b.) they've been working on their own CEC equivalent for quite a while. On the other hand, if their accounted threat are the Russians, they will not possess any of those capabilities at least for the mid-term. Same applies if they consider other kind of high-intensity naval conflict, for example a conflict in Eastern Mediterranean/Aegean region.

 

[H_K]

Sans any OTH sensors, a supersonic weapon can close with a surface target at low altitude and stealth is pointless. Against targets under an AWACs platform, a low RCS makes a lot more sense

I think there are a lot of assumptions baked into this statement that may be wrong.

My understanding is a big part of subsonic “stealth” is the lower sea skimming altitude of a subsonic missile, which enables it to hide better in sea clutter and reduces the radar detection horizon. The lower radiated heat also makes it less visible to ship-based IR sensors.

However, while this works against ship based sensors, I’m not sure the same applies against an AWACS. The 5-10m altitude difference may not meaningfully change the background clutter problem for a look-down radar with Doppler filtering. So radar detection ranges may be similar. As for long-distance IR detection, it can be challenging in look-down mode through clouds and tropical haze (China Sea scenario).

There are other signature reduction techniques like shaping and passive homing, however these aren’t exclusive to a subsonic missile and could also be applied to a supersonic missile (see MBDA Perseus concept).

So as to whether subsonic or supersonic missiles are more detectable by AWACS I think we really don’t know…

 

[Hood]

I think there is an element of pragmatism going on regarding size and launchers. Any navy wedded to box-containers is stuck with subsonic.
Voltzz's recent Bayern Chemie ducted ramjet finds loosely based on Meteor perhaps show the smallest hypersonic SSM that could be fielded. But sticking a booster on the back of the Meteor brings it the length to that better handled in a VLS.

But its being really optimistic that they can penetrate CIWS defences - and if they can then it says little good about current Western CIWS systems.

 

[Ainen]

I think there is an element of pragmatism going on regarding size and launchers. Any navy wedded to box-containers is stuck with subsonic.

Chinese (both) and now Pakistani beg to differ.

But its being really optimistic that they can penetrate CIWS defences - and if they can then it says little good about current Western CIWS systems.

Modern ships don't really have a lot of CIWS, nor they're something exceptionally exceptional.

We live in a weird age, where literally everything seems to work, one way or another - with unique sets of pros and cons, of course.
From slower-than-car swarming Iranian scooters to hypersonic ASCMs and ASBMs.

 

[H_K]

Any navy wedded to box-containers is stuck with subsonic.

Box launchers have 2 major advantages:

1) Easier installation - you can drop them in on almost any open deck and they weigh a lot less than a VLS with major structural reinforcements around it, and

2) The launch is much less visible due to the low angle and lower altitude reached by the missile. The latter is a significant advantage when trying to stay under the radar horizon.

And box launchers don’t care whether a missile is subsonic or supersonic so long as the deck space is big enough.