Geoff FordenMissile Development Consortiums

At left, is an Iranian numerically controlled lathe milling machine forming cooling channels in a rocket engine.

It is impossible to tell the scale of this engine — and therefore impossible to uniquely link it to the Safir second stage.

However, machining these channels, as opposed to using a corrugated insert, is a major technological change from SCUD technology.


David Wright and Ted Postol have done a really first rate job of analyzing the U’nha-2 and Safir development programs, as exemplified by their excellent article on the U’nha-2. But I think it is important to at least consider an alternative: these missiles represent a much larger portion of indigenous production than just assembling components. This is not to say that Wright and Postol are wrong in their conclusions, only to consider the question.

An International Missile Development Consortium?

North Korea is widely viewed as not testing their missiles enough before they sell them to “client” states. The Nodong missile, which forms the basis for the Shahab-3 and its variants, was tested successfully just once before “being sold to Iran and Pakistan.” This is an unreasonable flight test program and has led many to conjecture that North Korea is either buying complete missiles from Russia, missiles already engineered and developed, or missile components. That could, of course, be very possible and has unfortunate implications for the West’s relationship with Russia. Another alternative of this basic idea, just a small variant really, is that North Korea bought the production line for an obsolete or canceled missile system and modified it to fit its own special circumstances. With this head start, it then formed an international “consortium” with Iran and possibly Pakistan to continue the development. Moving its development program into other countries would have significant advantages for North Korea. For one, while Iranian missile launches are controversial, they do not appear as controversial as the DPRK’s missile tests. This is even more true for Pakistan where any controversy is mainly a regional one.

Such a development consortium would not be the first one ever created. The one I am most familiar with is the Badr 2000/Condor II development program where Iraq, in essence, funded the development of the missile by several other nations. Iraq received a number of contributory production plants that increased their capabilities considerably while failing to produce the desired missile. If North Korea bought the equipment for an obsolete or canceled production line, this would undoubtedly violate many of the rules of the MTCR but might not be as suspicious a violation, especially in a country suffering from the economic catastrophe that was Russia in the 1990s, as selling missile components. After all, most of the equipment could be considered dual use and could appear in separate manifests etc. All the subterfuges proliferation profiteers have used in the past. Importantly, it is much, much easier to reverse engineer a production line than it is to reverse engineer a missile component. After all, once you know the production line components, it is quite easy to buy similar or even exactly the same production equipment else where. The difficulty in reverse engineering is to infer the production scheme.

Too Advanced for Purchasing Production Lines?

An Iranian welding the Shahab engine injection head.
This illustrates the shop-floor know-how that is so
important — and so hard to acquire.

If this happened for the Nodong missile, is it possible it could also happen for an SS-N-6? In fact, it seems even more likely to me that it would happen for these more advanced missile components. The world is full of SA-2 engines, as Iraq showed by purchasing these engines in late 2002 ( see UNMOVIC’s Compendium, volume IV, p. 581.) The closer they get to strategic weapons, the more they come under the control of various treaties. (I’m not sure if SS-N-6 missiles ever came under any of the START etc. treaties, do any of you wonk-readers know?) It is possible that makes them harder to illicitly dispose of. It makes their production lines, however, that much more valuable.

( See my posting on estimating the costs of just the know-how associated with the Badr-2000. That alone was worth $75 million.)

What Proliferators Want

Proliferators, just as would-be producers of civilian products, want access to the technology and they are very seldom satisfied with just components. In fact, the financial inducements needed to entice developing countries into foregoing civilian technology transfer have to be considerable. It seems unreasonable that both Iran and North Korea would voluntarily put themselves into the situation David and Ted suggest, that they only have a finite number of components, and make themselves susceptible to the types of international restrictions that would eventually shut off their missile programs.


  1. Robot Economist (History)

    You are correct — SS-N-6 is included in the SLBM definition of the START Treaty.

  2. Azr@el (History)

    Dr. Postel’s and Dr. Wright’s article does not so much illuminate any aspect of the Unha-2 as it does shed light upon their collectively lack of equality to the challenge of analyzing Missile Designs in any serious manner. I’m aware of both of their competencies, neither of which is rocket design, this is made glaringly obvious when they assume that the SS-N-6 could be used as a high altitude 2nd stage. This assertion blatantly ignores that the Isayev OKB 4D10 and it’s variants are designed for sea launch; this would be the last engine one would place in an upper stage. Rather any nation possessing such an advanced closed-cycle engine would forgo inferior rocket engines such as No-Dong and utilize this high performance engine in the primary stage.

    There seems to be this “Lego” philosophy in vogue these days; where it is assumed that rocket stages across different families of designs are interchangeble blocks to be stacked and unstacked as fancy will take. I believe history suggest this not to be the case and rocket science not quite yet so trivial. I find the diameter of the Unha-2 second stage to be intriguing but I find the conclusion that because it’s roughly ~1.5m and thus must be the SS-N-6 to be an extreme case of dicto simpliciter.

  3. Pat Flannery (History)

    “It is impossible to tell the scale of this engine”?
    Actually, it’s pretty easy to tell the scale of this engine by looking at the crank handle on the machine holding it and the stream of water. The engine is pretty small, around eight to ten inches in diameter.

  4. Andrew Tubbiolo (History)

    Here’s what I see in that picture of the engine throat being machined. It’s a CNC manufacturing center maybe, but not a lathe. I think that is a rotary 4th stage on a CNC mill or a CNC manufacturing center. It looks small, maybe even like a hobby table top machine. Comparing the size of the shank in comparison with the coolant nipple makes me think that’s a 1/4” shank, 3/8th max. Which means that collet is only ~ 1 inch. Again, hints of a small machine. The handle on the tailstock might be a good source for a dimension. Most clamping handles are standard. Check the link for candidate lengths.

    Is there a link to the orig video? If I can get a look at more of the machine I can get a better idea of what class machine this is on and then size the engine. From what I see so far this looks small maybe less than 5” in diameter. 3rd stage engine, or one of many for a second stage?

  5. Geoff Forden (History)

    Unfortunately, the link that I had for the video has broken. (Perhaps other wonk-readers know where it is duplicated?) But it was a montage of very short clips that showed little, if any, additional parts of the milling machine (thanks for correcting me) or manufacturing center.

  6. Andrew Tubbiolo (History)

    Geoff, I hope this is not a problem. But the world’s CNC wonks are now reviewing the pic to ID the machine for you.

    What was the context for your web search? Perhaps we can find it elsewhere.

  7. Geoff Forden (History)

    A wonk-reader named Vic posted the link in an April 7th comment as

    Vic, are you there? Do you know where the file is today? I have a copy but its way too big to post here on ACW.

    I’m amazed that there are CNC wonks. What a great asset for ACW. More information is never a problem!

  8. Geoff Forden (History)

    I was wrong that the video did not show more of the milling machine. (I must have been focusing on the channels and not the machine.) Here is the widest field of view

  9. Andrew Tubbiolo (History)

    OKAY! Now that’s meaty! The machine is not small, we were not seeing the rest of the collet. The spindle is substantial. Let me chew on that tonight and post it as well. I’m sure we’ll get an answer within a few days.

  10. Andrew Tubbiolo (History)

    Looks like the rotary table is made by a high end machinery company from Ohio called Troyke ( I think it might be a DL-10-B series. Typical. Iranians love American equipment. Iran reminds me of pre WWI Germany when they lamented that the English would not let the Germans love them. A lot of Iranians I met in school lamented the same about the USA. Either way, another clue to throw out.

  11. Jochen Schischka (History)

    The picture obviously shows us a chamber of the Safir upper-stage – the approximate size and the type of technology (milled cooling channels in copper -> Isayev ZhRD 4D10) would match.

    But please keep in mind that the article shown in the video does not neccessarily have to be of sufficient quality to work properly. This could perhaps be only a non-functional dummy or the (unsuccessful?) result of a reverse-engineering experiment!

    P.S.: For once, i agree with Azr@el: i also don’t think the second stage of the Eunha was a (more or less unmodified) SS-N-6; But i explicitly do not exclude the possibility of SS-N-6-components (especially considering production equipment – the similarity in diameter is too intriguing) being used. I just think it’s more likely that a different engine (modified NoDong?) and TVC-concept (jet vanes?) were applied, but that is only speculation.
    I’d also caution against blindly assuming identical “common upper blocks” on Safir IRILV and Eunha (i see possible inconsistencies considering the delta-v-capability of the upper stages of both launchers; although the outer dimensions may be somewhat similar, that does neither mean they are in fact identically-sized nor that they are identically arranged internally).
    More details of the Eunha upper stages (especially considering the engines – but tank-volume-ratios or radar-tracking-data would also help) are desperately needed before we can dare to make any substantiated assessments!

  12. Jochen Schischka (History)

    A little afterthought on the Eunha’s second stage engine: Another possibility may be that the DPRK acquired one of the many, many russian-designed high-efficiency upper-stage engines via the same channels as all the other ancient/obsolete russian stuff…

  13. John Field (History)

    >>> “I’m amazed that there are CNC wonks.”
    Actually, Geoff, I have a 10 hp 4-axis CNC in my garage for making climbing gear.

    I concur with Andrew generally. This is a vertical CNC mill with a 4th axis rotary table. The cooling hose is adjustable by bending arbitrarily at each of the bumps. They are pretty standard and about 1/2” per bump. Also, the coolant opening is usually a little more than 1/4” (remember that flow goes more or less as pipe size cubed, so the dimensions can’t be very far from that else the coolant flow is zilch or a fire hose). That is consistent with a hand crank cross section of about 1/2” also. The implication is that this is a pretty small machine – and a pretty small rocket nozzle.

    Furthermore, the upper view of the spindle – polished slide and guide bar on the side is only consistent with a very small machine. Larger machines have the whole head move with the motor in order to increase the rigidity of the machine.

    That would make the cutter shank probably 3/8” in agreement with Andrew – although it could be 1/2”. It appears to be a side keyseat cutter. The black part at the top of the cutter shank is the collet chuck tightening ring. If the machine has a tool changer, that would be something like a CAT30 or a small NMTB size; in any event it is clearly smaller than the CAT40 toolholders that I run. I’d guess that this is about a 3 horsepower vertical mill with 12 inches of travel. The rocket nozzle is 4 maybe 5 inches in diameter.

    I think…

  14. Omar Beria

    One thought that crossed my mind on the original Unha launch was: what if they really only wanted to test a two stage missile, with the third stage and “satellite” being not much more than dummies?

    This would have allowed them to test the first and second stages (which obviously worked) and the separation of the third (which later on did not work).

    So they could claim it was a failed satellite launch, which was at least no as provoking as testing a pure two-stage ICBM-attempt.

  15. Geoff Forden (History)

    Perhaps I should have said I was amazed that there was world network of CNC wonks, though why that should surprise me in this internet age, I have no idea. I only wanted to express appreciation for this expertise working to solve this issue. I’ll have to check my log book for my estimate of the Safir’s second stage engine diameters. But the two sizes don’t seem inconsistent.

  16. Andrew Tubbiolo (History)

    Perhaps a list of historical systems can be compiled with a list of the machine tools used to manufacture them. Then you could use machine tool sales reports to to see if a nation has the raw physical ability to manufacture a particular class of system.

  17. Pat Flannery (History)

    John Field wrote:
    “I’d guess that this is about a 3 horsepower vertical mill with 12 inches of travel. The rocket nozzle is 4 maybe 5 inches in diameter.”
    I don’t think it’s a exhaust nozzle, but rather lower part of a combustion chamber being made. If you look at the wide end of the object being milled it turns into a cylindrical shape, which would be odd for a exhaust nozzle.
    What is odd is the small size; this would be something like a vernier engine as far as thrust goes for any good-sized missile unless it’s the engine for a very small liquid-fueled third stage, and one would think that a solid motor would be a lot easier to employ for that.

  18. Allen Thomson (History)

    > What is odd is the small size; this would be something like a vernier engine as far as thrust goes for any good-sized missile unless it’s the engine for a very small liquid-fueled third stage, and one would think that a solid motor would be a lot easier to employ for that.

    Well, I’d first note that we’re all way out in speculation-land here. But I’m OK with that and offer the following:

    The PBV engines on American and Soviet ICBMs are small and use liquid fuel. What the liquid fuel offers is the option to precisely steer and target the payload as well as (like a solid-fuel stage) to extend the range.

  19. Geoff Forden (History)

    It is hard to find a good, clear image of the Safir 2nd stage engines but this image probably shows one:

    If so, it seems very consistent with the combustion chamber being the same diameter as what John Field estimated. I think the evidence is growing that Iran (and presumably North Korea) has the capability to manufacture the advanced engines needed for the second stage and not to just use components. There is, of course, no evidence one way or the other for indigenous turbopump production.

    (note: for some reason, there appears to be a distortion in this image.)

  20. Azr@el (History)

    Looks like an Iranian modification to SA-2/Volga sustainer engine combustion chamber. They manufacture an extended range version of the Guideline under the nomenclature “Sayyad-1”.

  21. Andrew Tubbiolo (History)

    Perhaps it’s a thruster for 3rd stage post burn out trimming? Or maybe a small pressure fed ullage engine? Regen cooling is for hot, high Isp engines that burn a long time. All that plumbing requires a large amount of minimal fuel per burst if it were a thruster. Most thrusters are cooled by radiation. I’m more in favor of the vernier theory. That is assuming it’s a flight engine. No new news on what machine it might be. The uniformity in paint makes me think that the rotary table might have come with the machine which if true throws out the Troyke DL-10-B theory. Still chewing on machine ID.

  22. Pat Flannery (History)

    The SA-2 (S-75) sustainer engine combustion chamber was the first thing that came to mind when I noted the size of the object being machined.
    It looks too high thrust for use as a PBV velocity trim engine, which might well use hydrazine monopropellant for simplicity, rather than hypergolics.
    Is any gimbaling used on the first or second stage? Because if it’s not, then four of these engines could well be supplying pitch, yaw, and roll control, which would be a well-proven Russian technique.
    There are a couple of photos of a SA-2 sustainer engine in this UN report PDF:
    But the combustion chamber looks considerably longer than the one in the photo.
    (I was amazed to see that it is actually turbopump driven rather than simply pressure fed. Considering the time-frame the SA-2 comes out of and the small size of the engine that’s pretty impressive).

  23. SAE

    There are a number of local manufacturers of machine tools in iran which produce CNC machines. Have a look at this url:

  24. Jochen Schischka (History)

    To Azr@el and Pat Flannery:

    Nope, the Isayev S2.720 (aka the SA-2 engine) definitely uses corrugated steel as wall material, not, as can be clearly seen in in the pictures of the iranian engine, milled copper!

    Apart from this, i think the iranian engine is somewhat smaller than the SA-2-engine (d-throat: 70mm; d-exit: 200mm).

    Please check out the Isayev ZhRD 4D10 (the two-chamber vernier engine of the R-27/SS-N-6/Serb).

    BTW, in the same video we can see the complete engine installed in the Safir upper stage: it has definitely only two gimballed chambers fed by a common turbopump (exactly like the Serb-vernier);

    P.S.: And don’t get fooled by the fact that the Iranians added a radiation-cooled nozzle-extension to the R-27’s steering thrusters to adjust the expansion ratio to high-altitude conditions – in the photo Geoff posted, you can clearly recognize the added extension (it has a lighter color than the reactively cooled original portion of the Serb-vernier-chamber).

  25. Azr@el (History)

    First happy 4th of July all, the birthday of the modern experiment in democracy which inspired Euro-land to give the whole voting thing a go.

    2nd, to the best of my knowledge the IRI never got a Sa-2 factory from the Ruskies, DPRK nor the PRC, therefore chances are very good the Iranians reverse engineered whichever version of the s2.720 they have. Therefore it would be hasty to assume they are using corrugated steel as opposed to milled copper. They may have never mastered the Russian trick of reliable quality corrugated walls. Their sa-2 copy may very well have copper wall linings , let’s not jump to conclusions.

    BTW, the Isayev ZhRD 4D10 it also doesn’t use milled copper?

  26. Andrew Tubbiolo (History)

    Update from CNC wonks. The CNC wonks have come in with a first pass at the machine ID. Looks like I was wrong about the rotary stage after all. The best opinion yet is that the machine is a Fehlmann Picomax 20. Made in Switzerland. One CNC wonker says that Iran has a manufacturing license with a German company called Deckel. Deckel machines are held in high esteem around the world. Looking at this picture the spindle and spindle guide look pretty close if you accept that the Iranian video is flipped about the vertical axis.

    Might it be local per SAE’s find? Sure, I still consider this problem open, but at least we’re starting to get some candidates. I think the clincher might come from the roatary table as it looks like the 4 axis came with the machine by nature of the paint being an exact match.

  27. Andrew Tubbiolo (History)

    Following SAE’s Iranian link you’ll find they manufacture 2 mills. Looking for further information about these mills based on model numbers shows them to be remakes of Deckel equipment. I cannot find any good images or drawings of the spindle, but at the paint level, and the milling table, any of those two local machine might be it. Good catch.

  28. Jochen Schischka (History)


    The iranian SA-2B/Guideline mod.1 seem to be chinese-made HQ-2’s; i don’t think they are producing them themselves (BTW, that missile uses the Isayev S2.711V). May i remind you that the Iranians were so kind to exhibit an example of that engine during the February-display this year in Teheran – and it could be clearly seen on the picture Tal Inbar posted that the exhibited chamber was definitely corrugated steel.

    In contrast to what you wrote, assuming that a chinese-produced SA-2B has different engines with copper wall linings would be jumping to conclusions in my opinion. For what reason should somebody design a completely different engine with identical thrust-profile for an old (and openly available on the international market) missile?

    Granted, i’m not 100% sure that the vernier-chambers of the 4D10 are made of milled copper – but i’m sure about the main chamber (which is a high-pressure closed-cycle type! I don’t think that something like this can work with anything else but reactively-cooled copper…well, maybe reactively-cooled C/C-ceramics, but that is still a thing of the future, AFAIK, and irrational to assume for the Iranians); The small vernier-chambers seem to be quite high-pressure/high-temperature, too, if they need copper-chambers (and thus are not as low-tech as i initially assumed – still, i’d expect the large main-chamber to be a lot more challenging to produce)…

    Has anybody more detailed information on the dismantling-process of the R-27/SS-N-6/Serb missiles used back in the 90ies? Did the Russians cut up the main chambers? Did they do the same thing with the vernier-chambers? (If the latter was not the case, then this could perhaps explain where the Iranians got that engine from – procured, not produced. As i mentioned before, the part on the milling machine is not neccessarily/automatically of adequate quality for a flight-unit – and milling alone is not enough. The cooling channels also have to be closed up by electroplating with Nickel etc., etc., etc…)

  29. Jochen Schischka (History)

    To Andrew Tubbiolo:

    Aaaah, Deckel machines! They were precise, rugged and repairable – i’d give one finger of my left hand for each an original Deckel lathe and a milling machine in my basement…unfortunately, Friedrich Deckel GmbH (Deckel Maho AG from 1993 on) went bankrupt in 1994 (still don’t know how that could happen – obviously, nowadays it doesn’t pay off to make long-living high-quality items)…

  30. Geoff Forden (History)

    Jochen, I’m glad you mentioned the nickel platting of the copper cooling channels. It explains this image that I’ve been puzzling over:

    which comes from the same video of the Iranian production line.

  31. Andrew Tubbiolo (History)

    Jochen, America had the same problem. Our machine tools were of such high quality they remain working even after decades of duty. Almost all of them have gone out of business. Unfortunately Marx was right about the problems of capitalism just not the solution to those problems. I have machines in my garage from WWII that still do precision work. With minimal work these machine could last 100 years and still do useful work in the hands of a skilled operator.

    Geoff, is there any way you can get that file to us? I can set up access to an account for you to transfer it to. If there are no copyright issues or other legal worries we really need to get more eyes on this to pry the secrets out into the open.

  32. Andrew Tubbiolo (History)

    Yet another potential source for that machine. Well independence is a central precept of Juche. So I guess this should not come as a surprise.

  33. Jochen Schischka (History)

    Another very interesting picture, Geoff!

    I think it’s evident by now that the Iranians try to manufacture this engine by themselves (or at least try to create the impression that they are able to do this – building components like these is quite challenging and we don’t have a guarantee that what we see in the video is of sufficient quality for a live-fire article, do we?).

    If this is in fact the case and the resulting engine really works, then i’m rather sure that the degree of professional (russian?) help in establishing that production line was quite high (apart from the machines themselves and the knowledge about which machines exactly you need, this also requires a lot of know-how, e.g. considering the exact material composition, material properties, geometry, tolerances, etc. of the workpiece aka a full documentation, but also a deeper insight in the general production processes involved – all in all not gainable to a sufficient level by simple means aka reverse-engineering in my opinion…).

  34. Jochen Schischka (History)

    Hmm, after looking more closely at the last picture, i noticed that this is not the chamber, but the belonging nozzle (and the silvery color probably has nothing to do with electroplating – the cooling channels are neither sealed with filler-material nor closed up by a Nickel-layer – it’s more likely that the whole part is made of some sort of high-temperature-alloy).

    Please notice the horizontal slot – i think this is for the oxidiser-inlet pleat; I also think that there are indications for additional film-cooling (some of the cooling channels seem to be dead-ended).

  35. Geoff Forden (History)

    Andrew, I will post at least a part of the video on youtube today. I’ll let you (and, of course, all the other wonk-readers) the url when I do. Again, thanks to you and your world-wide network of CNC-wonks for working on this!

  36. Geoff Forden (History)

    Here is the first section of the video:

    Unfortunately, there really isn’t much more detail than the stills show.

  37. Andrew Tubbiolo (History)

    Okay we have an I.D. It’s a Fehlmann Picomax 100 CNC. It’s not a high end CNC, almost a hobby machine as we thought before. Geoff, I’m going to mail you a pic, can you post it? I’ll get the product brochure and get some decent dims posted.

  38. Geoff Forden (History)

    Andrew Tubbiolo writes:
    “Here’s a pic of the machine being used to mill the copper. As you can see it’s a dead ringer. Really, this is hobby machine. I’m sure its sitting in a lot of garages.”

  39. Andrew Tubbiolo (History)

    Sorry for the late link folks, but here’s the data on the basic dims of the machine we think is machining those regen cooling channels.

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