Geoff FordenDo You Know What This Thing Is?

click on the image for a larger version

The Iranian video apparently showing some of the manufacturing stages of the Safir two stage rocket still has a lot of information that needs to be analyzed. One important aspect is a brief montage of this furnace and a cylinder obviously cooling down. I think it might be a rotatable vacuum furnace for brazing the Safir’s second stage engines but I’m not an expert on that technology. We have, as I have recently found out, a world full of expertise in the ACW community that I would like to exploit to answer some of these questions. So the problem for the ACW-community is if anyone else has a better idea/knowledge about this thing. The cylinder is shown here and is obviously cooling off, with the outer radius cooling off faster than the heavier mass/smaller surface area support pipe. My guess, and I’m not the artist that Jeffrey obviously is, is shown here.

If this is a vacuum furnace, it appears in the same region of the video as engine construction and I think it would be one more piece of important evidence that Iran is fabricating its own engines.

Note: I have brightened and increased the contrast of the furnace image but there appears to be some thing attached to the front face on the non-adjusted photo that could just be the cylinder.

This post became part of series that consists of:
0) Do You Know What This Thing Is?

1) Iranian Furnances

2) The Jet Vane Hypothesis

3) The How of Proliferation, Part 1

4) The How of Proliferation, Part 2

5) Iran’s Composites Infrastructure


  1. Andrew Tubbiolo (History)

    In the screen cap there’s little variance in the color for the furnace interior to process out any details. Did you ever post a link to the orig vid?

    I’ve cross posted to the machine tool crowd, let’s see if we get an answer. Such machines are totally out of my experience.

  2. Geoff Forden (History)

    Hi Andrew, the section of the video that has this furnace is linked to in the first sentence. I hope there is a vacuum furnace wonk group out there!

  3. Jochen Schischka (History)

    My guess is, too, that this shows indeed a vacuum furnace (can’t tell what type, though – let’s see if somebody can accurately identify that thing…) – but not for the Safir’s second stage engine (which is, if i’m correct, not corrugated steel and thus brazed, but milled copper with an electroplated outer layer -> completely different technology!).
    Exactly such vacuum furnace would be needed for brazing the Nodong-chamber (which is corrugated steel technology like the Isayev 9D21, and i think the dimensions might be approximately right) for the Safir’s first stage.
    Please note that in the same video a Scud-like baffle can be seen as it’s hand-welded to a chamber-head about the right size for a Nodong-engine…so maybe we can also gain some additional insight into Nodong-engine-production from that source.

  4. Geoff Forden (History)

    Jochen, If they don’t braze the inner and out shells for the second stage engine, how would they bind them together?

  5. Jochen Schischka (History)


    Electroplating is the magic word: you start with an (inner) copper body in which you’re milling cooling channels; these channels (and only the channels!) are then sealed with some sort of wax; next, an even outer layer of nickel (several millimeters!) is applied galvanically over all; finally the wax is melted out; voila – chamber ready (actually, you’ll have to join the chamber and the nozzle/reactively-cooled nozzle-extension before electrodepositioning; as i understand, this is the only thing done via brazing in that type of technology – but, AFAIK, without the need for a vacuum furnace)!

    Check out the production process e.g. of the SSME (Shuttle) or the Vulcain (Ariane 5) for more details (since this is only a simplified version of that rather complicated operation)…

    In contrast, the “corrugated steel” technology (e.g. S2.711V, S2.720, 9D21 etc.) uses an inner shell, a corrugated inlay (this later forms the cooling channels) and an outer shell made of some sort of heat-/chemically-resistant steel; these pieces are initially severed at the throat (which itself is a seperate part with drilled longitudinal cooling channels) for assembly and then bit by bit get welded together (but the corrugated inlay still isn’t bonded to both shells at that time, although the filler material is already applied; it’s held in place because it is welded to the throat-piece); next comes “baking”: in a vacuum furnace, the complete chamber/nozzle-assembly is heated by electrical induction – this melts the filler and brazes everything together.

    For a better understanding of the latter process, take a close look at sectioned examples of a Guideline-, Gammon- or Scud-engine. Then it should become obvious.

    (BTW: The Iraqis apparently failed in their try at the “corrugated steel” method – their “rev-eng”-chambers were of insufficient quality…)

    I think we see elements of both types of technology in the iranian video (although we still have no guarantee that the parts apparently produced are of sufficient quality – which i personally doubt, since especially the copper/electrodepositioning-method is rather challenging; plus, i have not yet found any evidence for electroplating in that particular video…)

  6. bradley laing (History)

    MOSCOW — It was intended to be a symbol of Russia’s post-Soviet military might. The nuclear-armed Bulava missile would be unlike any weapon in the world in its speed, accuracy and ability to defeat any defense the West might throw up, Russian officials claimed, helping to propel the country’s armed forces into the 21st century.

    Today, however, the Bulava is having trouble just propelling itself.

    A test flight in December went wildly off course. So did a string of launchings in 2006 and 2007. Only half the tests since 2003 have been even partly successful.

    —From a July 15 New York Times article.

  7. George William Herbert (History)

    They don’t necessarily have to be connected, other than at the ends.

    Plenty of the modern rockets use an outer sleeve over an inner combustion chamber liner, with milled cooling channels in the inner liner. The outer sleeve is under tension – pressure inside it.

    The inner liner is under compression, as there’s higher pressure in the cooling channels than in the chamber; you always get pressure drop in the injector, usually 20-30%.

    To strengthen the liner against compressive buckling, ideally you’d mill the channels circumferencially around it, so the ribs are acting directly in the direction of maximum compressive stress (like ribs in a submarine – Russian subs even use ribs external to the main pressure hull, in the same geometry, versus western ones with internal ribs).

    However, when you do that, cooling evenly becomes an issue. You have to inject cooling propellant along one side, or along a series of axial channels, and the cooling is at its least effective when you get around to the channels that collect the propellant to deliver it to the injector.

    So everyone runs the channels axially, so that the cooling is even all the way around at any given distance from the injector.

    You have to seal the top and bottom of the inner combustion chamber liner / outer sleeve connections, and you usually have to put some sort of internal barrier / sabot around the throat to keep the coolant up against the inner wall as the throat narrows down, but those are well known. You can use screw connections, or welds, at the top and bottom. Those joint areas are all exposed.

  8. Jochen Schischka (History)

    To George William Herbert:

    Hmmm, i somehow doubt that the method you’re describing is applicable to high-pressure/high-temperature engines (like 100bars chamber-pressure upwards – otherwise, using copper is unjustifyable in my eyes).
    How is that type of chamber assembled? Is the outer jacket or the “throat sabot” longitudinally divided (not an exceptionally favorable solution for the noise-levels and heat-stresses generally associated with rocket engines, if you ask me)?
    Also, doesn’t really sound weight-efficient to me, neither.
    Realizable, perhaps (with low to moderate chamber pressures), and quite interesting from a manufacturing/maintenance-centered point of view, but well…

    All in all, this reminds me strikingly of the HWK-109-509 of the Messerschmitt Me-163.

    Let’s not forget that many of these never leave the ground (or even the drawing board)!
    (And that many of these projects never even intend to reach space aka anything near orbital velocity – but that’s definitely an entirely different story.)

  9. Jochen Schischka (History)

    A point i’m starting to second-guess:

    Is it actually feasible chemically to combine copper and a NTO/UDMH propellant combination (i think OFHC-copper automatically drops out of the equation)? I know there are issues with MMH or pure hydrazine, but what about UDMH?
    What type of copper-alloy can potentially endure cooling via UDMH (or even NTO???) for the required burn-times? CuAgZn? CuCr?
    Could perhaps some sort of fuel-additive inhibit a possible corrosive effect?

    How did the Russians accomplish this in case of the Isayev 4D10 (or alternatively, if not by reactively-cooled copper, how else did they deal with the heat-flux-problem)?

  10. Geoff Forden (History)

    A wonk-reader wrote me off line to suggest that this furnace is “mainly used in Iran for sintering the rocket steering paddle [jet vanes], made of high grade graphite covered with carbon fiber and ceramics.” This very interesting suggestion, which I now like much more than my original hypothesis, opens up a whole new line of research. I will have a lot more to say about this when I return from Shanghai.

  11. Azr@el (History)

    In the 1960’s the soviets used titanium and we used nickel when utilizing nto, kerosene, mmh or udmh for regenerative cooling. I believe everyone eventually migrated to stainless steel, another steel alloy or treatments of iron-nickel-chromium, i.e. Iconel, for such purposes.

  12. Jochen Schischka (History)


    Right, except for the Russians:

    Check out e.g. the RD-253 (the first stage engine of the Proton) – reactively (and additionally film-) cooled (by UDMH) copper chamber plus NTO/UDMHexactly like the small engine we saw in the iranian video, only much larger!

    So, now that we know it can be done, i ask again: How exactly is this possible?

    BTW, i doubt that chamber pressures of over 150bar (and the accompaning heat-flux) can be mastered without the superior thermal properties of copper alloys (after some research, you might notice that everything with storable propellants and steel/nickel chambers in the west is fairly below 100bar).

  13. Jochen Schischka (History)


    If this “oven” is used for sintering graphite jet vanes (or rather for sintering a ceramical surface coating onto them?), then why the cylindrical form (which would, on the other hand, make sense to me for the containment of a thrust chamber)?
    I don’t want to say that this is not a possibility, but then i’d like to understand why they chose that particular shape and not e.g. something box-like.

  14. Geoff Forden (History)

    Jochen, good question but Im afraid it will have to wait until I am back from China. I need to think about this possibility and then I plan on writing a longer piece about it.

  15. Azr@el (History)

    Did anyone notice that in the original video they use frames of this octagonal microsat:

    not frames of the cubic omid.

  16. Jochen Schischka (History)

    Indeed, a different satellite than Omid; Since i’d expect the next iranian satellite launch in August or September (22. would be a particularly interesting date for the Iranians, but let’s see…), this is possibly “Omid-2” or something like that. Or a mock-up (it wouldn’t make a lot of sense to fit the satellite on top of the second stage months before the launch attempt) of a future satellite.

    BTW, we can see some interesting details of the guidance system of the Safir on that picture; Particularly, note the positioning of the cable duct and how this coincides with the location of that rounded box-like structure.

    Can anybody positively identify this “box” (preferably with pictures for comparison)? I can only say that this is definitely no 3-axis gyroscopic platform (which are typically approximately spherical), and it doesn’t look like a 1SB11 Horizont/Vertikant-platform, either (but i don’t want to exclude this possibility, since the Iranians could have “repackaged” that one).

    Unfortunately, the “tin foil” obstructs the view on more details (like the energy source or a possible pressure-gas-torus)…

  17. Azr@el (History)

    The rounded box is the strapdown ring laser gyro inertial system.

    And whereas there are no papers describing the fabrication of an Iranian ring laser gyro; there are articles regarding the fabrication of supporting element and half a dozen CV’s of Iranian engineers and scientist who claim to have designed and implemented a fiber optic ring laser gyro.

  18. Jochen Schischka (History)


    Definitely a possibility (especially in combination with the Safir; notice that there is no distinct ~850+mm long guidance compartment with four rectangular hatches on that type of missile…).

    Unfortunately, an article about simulating a LINS is no evidence for the “box” to really contain one of these, only of the Iranians studying this technology. This i do not doubt. But are they able to produce this yet? I’m not so sure (i allow me to be very careful with claims by iranian scientists/engineers; if everything they claim would be anywhere near true, then iranian T-72-tanks would be better than M1A2s, each Ghadir/Sang-O-minisub would have a higher strategic value than an entire carrier-task-group and putting the Hawk-SAM on the F-14 would be even superior to using the original AIM-54s, not to mention that they single-handedly defeated Saddam in GW1…we should not forget that the Iran goes through an ultranationalistic phase, especially right at the moment!). And then the question about sufficient quality and/or suitability for missile-application is still open. But of course import is, as always, an option. (BTW, i’d suspect a chinese or possibly even an indian origin, if this should be the case – any pictures of their LINSes?)

    An independent photo of a (still hypothetical) iranian (or chinese or perhaps indian – i can exclude american- and european-produced devices by now) LINS for comparison would answer a lot of open questions, but unfortunately i haven’t found one so far (any help welcome!)…

  19. Azr@el (History)

    Your description Jochen is also reminiscent of our ballistic missile defense contractors. I believe hyperbole is the default communication protocol for defense contractors, defense officials and nationalistic fanboys the world over, but I very much doubt that prestigious scientist would fib on their CV, irrespective of their national origin.

    With respect to an indigenous Iranian capacity for a laser ring gyro, I tend to favour the logic of occam’s razor. If the Iranians wanted an off the shelf laser ring gyro, they have hundreds if not thousands of specimens in country from which to cannibalize one. Laser ring gyros are not that hard to come by on the open market, afterall I have a FOG one in my car. Why invest the time and energy in developing the supporting industries if not for indigenous production.

  20. Jochen Schischka (History)

    Azr@el, if we’d apply occam’s razor consequently, then our working hypothesis should be that the ‘box’ contains a repackaged 1SB11 gyroscopic platform (easier to produce, easier to customize, already in iranian service; but, as i wrote before, i don’t want to exclude other possibilities), since that would be a simpler explanation, right? Other, as-simple-as-can explanations could be that the ‘box’ contains the battery or other parts of the guidance system (like e.g. the disributor box – something i’d expect to be positioned directly next to the cable duct) – we can’t exclude all these possibilities based on the available photographic material at the moment (i suggest we wait for additional evidence before committing ourselves hastily to one single theory); And import is a less sophisticated means of acquiring high-tech equipment than indigenous development without former expertise on that sector, isn’t it?

    “…is also reminiscent of our ballistic missile defense contractors.”

    Absolutely true. I wouldn’t buy a used car from those guys…

    “but I very much doubt that prestigious scientist would fib on their CV”

    Well, you may call me a burnt child dreading the fire; I obviously was overdosed with too much bogus eastern bloc anti-west, anti-‘imperialist’, anti-‘fascist’ ‘communistic-superiority’ propaganda during the cold-war era (and acquired too much knowledge of nazi-german activities in that department, too) to trust anybodys assertions (irrelevant if ‘prestigious scientist’ or not) without a little reality-check and/or additional evidence, especially if high-ranking politicians from that particular state frequently use reminiscent anti-western-style (or worse) rhetoric…