Geoff FordenThe Year of the Rocket

Rocket Country Date Propellant Stages Purpose Note
Kavoshgar Iran 4 Feb 08 Liquid 1 unknown successful
Safir Iran 17 Aug 08 liquid 2 satellite launch failed during 2nd stage
Sajil Iran 13 Nov 08 Solid 1 or 2 Solid propel. develop. successful
Kavosh Iran 26 Nov 08 Solid 1 Study stage separation successful
Safir-2 Iran 3 Feb 09 Liquid 2 satellite launch successful
Unha-2 DPRK 5 Apr 09 Liquid 3 Satellite launch Failed after 2nd stage
Sajil Iran 20 May 09 Solid 2 solid propel. develop. successful

solid propel. develop. is solid propellent development.

The past “year” (slightly more, really; it stretches from February 2008 to now) has been a very active one for countries developing missile technology. I thought today’s launch of an Iranian Sajil solid propellant missile would be a good occasion to review all that has happened. So here is a table I’ve composed of “all” the rocket launches since the Kavoshgar launch in February 2008.

Comments

  1. V.S. (History)

    And let’s not forget that India at the same period had many, many launches. How many really?

  2. Azr@el (History)

    A plethora of nations have pierced the stratosphere with rockets this past year; but save for disruptive players, DPRK and IRI, they are all more less obedient and interdependent parts of the current world system such as India.

  3. Geoff Forden (History)

    Azr@el, thanks for pointing that out and in a much more poetic fashion than I would (or could) have.

  4. FSB

    How is IRI “disruptive”?

    They are a signatory to the NPT and do not possess nukes, UNLIKE some other middle east nations.

    Let’s stop throwing names around and keep it technical and wonky, shall we?

  5. Bill

    Has North Korea lost its edge? Traditionally, we believe that North Korea is the evil genius exporting missile technology to everyone we hate. However, it appears that North Korea has little to nothing on Iran, whose program is independent and as advanced or more advanced than NK’s.

  6. KB
  7. Geoff Forden (History)

    FSB has made the point many readers want to make about “disruptive.” The others that are coming in are little more than personal attacks so, please, lets move on.

  8. Pedram

    No movies. Just photos.

    Photoshop again? ISNA’s photos show bluish stains on the exhaust?

  9. Cernig (History)

    Here’s a still from the launch of that Iranian Sajil missile, and a FARS publicity still, provided by IRNA.:
    http://www.facebook.com/home.php#/photo.php?pid=2604567&id=564463744&ref=mf

    Same missile? To me, the second stage join looks different, as do the shape and lengths of both nose and tail sections.

  10. Cernig (History)

    That should read “provided by ISNA”, obviously.

  11. Geoff Forden (History)

    There are many interesting features in the pictures of the Sajil that have appeared today. One that interested me right away was the fact that the hall where the Sajil is shown is definitely different than the hall where the Safir was was displayed. What would be interesting, if others find more images of this hall, is one showing the overhead crane. The crane in the building with the Safir is a relatively light model. My guess is that the overhead crane in the Sajil building has considerably greater capacity (as one might expect). For instance, the Safir crane rail is supported on tiny little struts that project out from the building’s support structures while the Sajil’s overhead crane’s rail seems to rest on top of considerably more massive supports. If anybody does find such images, please post their url’s here. Thanks!

  12. Pedram

    First video is available on youtube. Apparently showing the second stage ignition and separation.

    Bad quality though.

  13. Tal Inbar

    There are many interesting features in the pictures of the Sejil that have appeared today. I agree completely!

    I am looking forward to hear what the supporters of the theory that Sejil is using LIQUID fueled thrusters has to say after they will examine the pictures of the missile in the hall with the Yellow tail.

    Thanks.

  14. Geoff Forden (History)

    The “supporters” (ie me) of the liquid thrusters theory appear to be wrong.

  15. PC (History)

    Thanks Geoff. I was under the impression that the first Sejil test failed. Is it clear now that it was successful?

    I would also add (though I’m not asking you to do so) the Nov. 27 test of the Ashura, which seemed to me to pave the way for the Sejil tests since it was Iran’s first flight test of a 2-stage solid-fuel MRBM. And from what I understand it is essentially the same system as the Sejil.

  16. Dr. P

    Ahmadinejad said the missile was “able to go beyond the atmosphere then come back and hit its target.”
    Does this mean that they are able to design and manufacture reentry vehicles with warheads?

  17. Geoff Forden (History)

    This image appears to show the staging of the Sajil. Note that there is no obvious break in the exhaust plume, indicating that ignition occurred while the first stage was still burning. I’m also wondering if the length of the broad exhaust trail indicates that the first stage “flew” (perhaps erratically) on after second stage ignition.

    PC:
    Its not clear what the purpose of the first test was. Clearly, they were successful in firing a large solid-propellant, guided missile. That is why it is listed as a success in the table. I had my doubts at the time, though perhaps for the wrong reasons, that the second stage was “live.” Its not clear if the second stage of the first test ignited, nor is it clear to me that it did not. So, if somebody wants to judge it a failure, I wont object too strongly.

  18. Tal Inbar

    I believe that the tip of the re-entry vehicle is made out of RCC.

    http://www.fresh.co.il/vBulletin/showpost.php?p=3346348&postcount=50

  19. Juan-John (History)

    Where did the doggone thing LAND??? One would assume within Iranian territory, right?

  20. AWR (History)

    The article in the WSJ today about Robert Morgenthau’s testimony to the Senate Foreign Relations Committee (the link is below) is very disturbing, and I wonder if anyone here is willing to parse it and make some technical observations (@FSB and Geoff)? I appreciate very much Geoff’s posts, which have made me an even more dangerous non-technical layman than I have ben in the past. Another item in the Journal article I find both interesting and disturbing is the noted SFRC staff report (does anybody have it?), because I have been there and done that, and once these things get used in a political context without the proper technical caveats, they can become political gunpowder. Sorry FSB, but this issue is highly political, as well as technical, and I don’t like the drumbeat any more than you do, but I fundamentally and respectfully disagree with your position.
    http://online.wsj.com/article/SB124268823646932231.html#mod=loomia?loomia_si=t0:a16:g2:r1:c0.238396:b24614476

  21. MN
  22. MN

    http://www.farsnews.com/plarg.php?nn=M533922.jpg

    The tested missile is blue, and the one on the rail is dark grey, in the following pics #6 & #4, you can see blue spots on the orange carrier, the launched missile also has an extra part on the body of the first stage.

  23. George William Herbert (History)

    No obvious break in the exhaust plume is not abnormal; if you look at yesterday’s Minotaur space launch vehicle launch video, for example, it’s hard to tell when staging happened.

    It’s easy to time the staging – when chamber pressure in stage N drops below a fixed value, where the upper stage motor will now accelerate itself away from the tailing off lower stage, you fire the N+1 igniters. This can avoid inconvenient gaps in thrust vector based attitude control … Just as first stage is starting to lose control authority, you fire the second and it takes over, etc.

  24. Azr@el (History)

    Does anyone wish to share some insight into the four steering modules of the base and second stages? Straight steering vanes a la the Shahabs, Indian style injection steering or pressure fed transpiration and film cooling of steering vanes?

  25. K.Y (History)

    Mostafa Najar (Defense Minister) said to reporters after the launch;

    “Compared to Sajil(1),Sajil 2 has a new navigation system as well as sophisticated and precise sensors which makes it more accurate (compared to the 1st generation).
    With improvement to the targeting system and launch platform our experts have been able to shorten the start-up time “

    http://www.mehrnews.com/fa/newsdetail.aspx?NewsID=882714

    This appears to be a test for a new guidance system (on the same Sajil 1 missile).

  26. Azr@el (History)

    Notes;
    I) Rocket seems to be going up fine, contrail seems distorted mainly by being blown around by the jet stream.

    II) The official line, which seems perfectly valid, is that the previous flight test was the integration of the propulsion system. The current one is the test of a a very similar propulsion system with a completely new guidance and control package. The new system is sufficiently different to warrant a new designation. I see no reason not to believe Teheran.

    III) My previous statement was in reference to why certain nations seem to take a disproportionate share of the media attention when they loft something up into the sky. My answer was from the viewpoint stateside, from the viewpoint of someone who believes that Pax America, American Hegemony irrespective of it’s shortcommings, has been a beneficial occurrence for the planet. To those who might differ with this view, I ask you to sincerely ponder the alternatives and gasp.

  27. FSB

    AWR,
    I favor a nuclear-weapons free zone in the middle east. Let’s start with the existing weapons.

    Why does Iran want (possibly) nukes and missiles? Maybe US and Israeli aggression in the region has a role in their decision making.

    e.g. Look at a map of Iran and note the names of the 2 countries on either side of Iran. Now check if those 2 countries have been in the news lately, and report back to the class as to why Iran may be worried and in search of deterrence.

  28. George William Herbert (History)

    Reverse engineering the warhead from the photos available so far…

    Warhead main cylinder dimensions are very close to 0.6 (0.597, with 2 useful significant figures) of body diameter, which for the public poorly documented 1.25 meter body diameter gives a 75 cm warhead cylinder section outer mold line.

    Nose half angle is somewhere between 22 and 25 degrees, a from-the-side warhead closeup would be nice.

    Nose is about 120 cm long, cylinder about 75 cm long, tail flare about 50 cm long.

    Volume of the cylindrical section is around 0.08 cubic meter, including the nose cone and tail flare is about 0.2 cubic meter. Filled most of the way with density = 1.65 high explosive (composition B or equiv), you can fit around 330 kilograms of high explosive in that envelope.

    Alternately, that’s big enough for a relatively compact multipoint spherical HEU nuclear fission weapon… The very large yield boosted Orange Herald device was about 75 cm outer diameter, though the useful warhead size in this warhead would be smaller (outer mold line plus structure and heat shield thickness, plus some packaging factor margin).

  29. Amir

    Hi all,

    Here is a set of high resolution images!
    The second image is the most interesting one and shows the nozzle section!! Clearing the steering debate.

    http://jamejamonline.ir/pics.aspx?newsnum=100907277288

    Do not forget to magnify them.

    Also, notice the blue paints on the crane; it suggests that the launched blue Sejil-2 was on the same crane before!!

  30. Andrew Tubbiolo (History)

    George Willam Herbert:
    “It’s easy to time the staging – when chamber pressure in stage N drops below a fixed value”

    I was shocked to find out that … shall we say the big boys of the American aerospace establishment, use open loop timers based on analysis and wind tunnel tests. While discussing Space-X’s miss-stage I expressed a similar idea of how to decide when to stage. Needless to say I was corrected as to how it’s been done for the past 50 years.

  31. MN

    It is so tragically comic that the US Government and other western countries have said so many times that they are NOT taking the “use of force option off the table” but then when Iran, in response to these uncivilized threats fortifies its defenses, they call Iran’s move provocative and threatening! [http://www.youtube.com/watch?v=oo4QbarMkBI]

  32. K.Y (History)

    @ Amir
    This is probably an empty frame in the assembly line (doesn’t even have paint on it).

  33. George William Herbert (History)

    Andrew:

    It depends on the vehicle.

    Scout was a timer, a gyro, and a electric motor that tipped the gyro over following a pitch progam per the timer.

    Some launchers use a full integrating goal seeking closed loop system.

    My comment regarding the stage attitude control was specifically looking at this missile’s attitude control – fairly stubby fins, and vanes in the nozzle exhaust (assuming that the new photos are accurate and complete enough). If your staging event is close enough after max-Q, you can end up with vehicles which are not aerodynamically stable near the end of a stage 1 burn, and you have to cut the stage 2 motor in rapidly to keep the vehicle from yawing out of control in the airstream as the first stage thrust tails off.

    Launch vehicles with more delta-V per stage can stage higher, and at lower dynamic pressure and less upset forces, so time criticality of the ignition can be lower.

    ICBMs, IRBMs, and multistage MRBMs and SRBMs particularly have a much tougher problem – they’re not going as high, they’re typically thrusting harder and shorter anyways. So max Q is worse and dynamic environment at staging can potentially be quite hairy.

    I don’t see enough info in the public domain to try and model the stage delta-Vs and the trajectory on this one, so it’s hard to tell what Q is at staging, and what aerodynamic stability looks like at that point. The stub fins help with that but Cg is in play too – we can tell how much volume is in the second stage, but not what the weight breakdown is necessarily.

    Could be an open loop pitch program, sure, but assuming that others did it that way necessarily because US predominant practice has been something like that is a mistake. It’s not always that, and there are reasons for selecting what option is used.

  34. George William Herbert (History)

    Ack. While I was typing my last message, I heard a thump in the living room. Finished entering it and then went out to see.

    Cats knocked down some books. “Nuclear Deception” and “Fundamentals of Radiation Hydrodynamics” were open, and the cats ran away when I walked in to the room.

    I sincerely hope that centrifuges require opposable thumbs. Otherwise we’re doomed.

  35. KB

    1- I thank “the supporter of liquid fueled thrusters” for creating an idea and letting us enjoy a discussion about it.

    2- To AWR:
    a) I would like to make an argument against politicizing discussion, but first I have to point it out by a political comment! Someone’s terrorist is the freedom fighter of another as it goes with political views. I am sure if you ask Middle Eastern people, there are nothing more “disruptive” and disturbing than pictures of Abu-gharib, perished life of innocents and …let’s not open the can of worms and stick to the memories of great Americans we all know and respect. This way we can enjoy naturally unbiased technical matters discussed in this valuable blog.
    b) With regard to Iran seeking “exotic” equipments, materials and capabilities: It is a bitter pill we have to swallow. When Iran was deprived of access to a reliable air power, which is a legitimate right, it turned its attention to missile development. By doing so, US forced what could be a mere tactical threat to a strategic one.

    3- Could the function of those fairing on second stages be different from the first stage?

    4- What are Iranians trying to hide (from a technical point of view) for exposing this much about their new missile? Another more advanced missile?

  36. BenjaminS

    Also, isn’t it weird that pipe on the side is missing in this version…why is that Geoff?

  37. Omid (History)

    Geoff I think you’re right.I have 2 images:

    It’s written in farsi:“second stage function”

    “Entering vacuum(space)”

    I’ve taken them from this video:
    http://www.iribnews.ir/News/Video/190803_84c08965.wmv

  38. Jochen Schischka (History)

    First of all, i’d say that it’s absolutely clear now that the “boxes” at the end of the missile do contain jet vane actuators. See for example this particular picture:

    Next, i’d like to point out that the type of staging apparently used on the Sejil is quite typical for military multi-stage solid-propellant missiles – the lower stage(s) is (are) not thrust-terminated, only the upper stage, and there is no noteworthy coast-phase between lower stage burnout and upper stage ignition (helps e.g. to minimize the length of overall boost phase and the resulting trajectory is more optimized for range, but of course, as mentioned before by George William Herbert, this also minimizes the time of flight without TVC).

    Another interesting point is the reentry vehicle (which is more or less identical to that of the Ghadr-1). Again, as George William Herbert already wrote, the volume of that thing is quite small and i don’t see any sign of post-boosting, alignment and/or spin-up (in fact, i interpret the flare at the rear as an indication for an only aerodynamically stabilized tumbling reentry -> no pin-point accuracy at the alleged range!) – so i’d assess this warhead as useless if not loaded with a nuclear payload (resulting in a RV-weight of ~600kg).
    BTW, i must say that CC-Ceramics usually are not that glossy black (like polished paint?), but rather some sort of dull dark-gray, although i have no doubt that this is in fact the material used on live missile-nose-cones (perhaps the missile in the hall is only a mock-up?).

    Oh, and did anybody else notice the ~half-year cycles of the iranian missile programs?

    Last but not least: Thanks to all who provided links to these excellent pictures/videos!

  39. JR (History)

    BenjaminS,

    It looks like the pipe on the first stage is present on the launch pad photos but not in the high bay. That gives me two different thoughts:

    1) The side pipes and boxes are a component that gets integrated late in the stackup process (something like first stage retros, maybe?) or

    2) The side pipes are some other integral component and the high-bay photos are not photographs of the system we saw on the pad.

    I’m inclined to go with the former.

  40. AWR (History)

    I ws trying to steer the conversation AWAY from the political and toward the technical. That is why I asked if anyone could shed some light on Iran’s procurement efforts as described by Morgenthau in his Senate testimony. I would also like to see the staff report for more info on the same subject. I made no comment about a MENWFZ, nor cast and aspersions on FSB’s or anyone else’s views. If read carefully, what I was saying was the staff report, the kind of thing I used to write and know quite a bit about, is part of a political context in which the US is trying to figure out how to deal with Iran. I still hope some of the real experts, as opposed to the dogmatists, can further educate me. @FSB and KB – If you want to charcterize my views, you might try reading my article iin YaleGlobal instead of slinging mud: http://yaleglobal.yale.edu/display.article?id=11793

  41. KB

    To AWR:

    I have nothing but respect for your views even I might not agree with them and if you felt offended by my comments, I sincerely apologize. Maybe I was so eager to make a case against politicizing discussion as we all have seen throughout other discussion how a genuinely great argument by experts was derailed by angry biased comments (which sometimes disappeared) and at the end frustrated moderator close downed the discussion.

  42. Mehrdad

    To Geoff Forden,

    I would like to clarify why Iran has been very active in testing new missile technologies during last year.

    Decision making model:

    Apparently, AIO is in the charge of the developing missile technology in Iran, which is supervised by the Revolutionary Guard. All test requests by Iranian scientists will be confirmed /rejected by the supreme leader and his defense advisors based on the political factors.

    This means that the Iranian president does not have any control over confirmation/rejection of these military tests, he can only play with political factors, e.g., disturbs the political situation by aggressive talks/statements.

    If you saw the BBC report on the Sejill-2, at the beginning, Mr. Ahmadinejad said to the audience in Semnan province “On the way coming here, they just notified me of a new missile test… [in Persian]”, which means he even was not aware of this new test ahead of time.

    Reasons for being very active (it is not only politics):

    (1) Iranian scientists are trying to get the maximum benefit out of the situation in the last year of Mr. Ahmadinejad presidency; most of their test requests have been confirmed by the supreme leader because of the political factors. This may not be the case after the June election if a moderate candidate gets the power in Iran. If you come back to the second period of the Mr. Khatami presidency, they suspended most of the Iranian sensitive research programs such as uranium enrichment, missile development, etc. Although they were active in their underground research labs, they could not have repetitive tests.

    (2) Iran has received continuous threats from the US/Israeli Government during last year. These tests are a natural reaction to those threats.

    My hypotheses:

    (a) It is not surprising if Iran tests new missiles and/or centrifuges (or related techs) in the next four weeks till June presidential election.

    (b) Iran will not test any more ballistic missiles during next year (probably more) unless Mr. Ahmadinejad is re-elected and/or Iran receives more threats from the western countries.

    © Iran will focus on the peaceful satellite lunch during the next three years; probably they lunch the next missile in late 2009/early 2010 for higher level orbits.

  43. b (History)

    @JR – “It looks like the pipe on the first stage is present on the launch pad photos but not in the high bay. That gives me two different thoughts:”

    If on checks the highbay-holders they have two pockets where the side-pockets will eventually be installed.

    The missile in the highbay probably something taken out of the production line to show off some details together with the recent lauch. The warhead-cylinder appears to lack welding, the vane actuators are missing as are the side pipes and the control lines.

  44. b (History)

    @Mehrdad –

    /quote/This means that the Iranian president does not have any control over confirmation/rejection of these military tests, he can only play with political factors, e.g., disturbs the political situation by aggressive talks/statements.

    If you saw the BBC report on the Sejill-2, at the beginning, Mr. Ahmadinejad said to the audience in Semnan province “On the way coming here, they just notified me of a new missile test… [in Persian]”, which means he even was not aware of this new test ahead of time./quote/

    Ahmadinejad was certainly aware of the missile launch. I would even claim that he had planed it for exactly that day.

    This was Ahmedinejad’s last allowed travel into the provinces.

    From now on it is election season and it is official forbidden for him to do such state payed travels/rallies during the campaign season.

    Semnan is also the province where Ahmadinejad’s family comes from and where a big part of the missile industry is.

    This whole launch was certainly timed to give Ahmadinejad a nice big rally event.

    He is a politician after all and not much different than our politicians.

  45. Pedram

    Question for experts:

    In the photos when it entered “vacuum space” the second stage white exhaust disappeared. Does it mean the warhead separated from the second stage or the second stage was working and its exhaust disappeared due to “vacuum” effect?

  46. Mehrdad

    @b

    I am not trying to convince you, but without any doubt he was not aware of that test. The problem is that, most of the politicians/people in the west are not aware of the Iranian decision-making/authority model.

    By the way, I should say that, from 16 years ago, Iran has launched its missiles from either Ghom or Semnan; being from Semnan province does not have any relation to the predetermined launcher sites. Moreover, most of the missile industries are located in Tehran and Isfahan.

  47. George William Herbert (History)

    b –

    In the highbay photos, where would you be looking for welding on the warhead that isn’t there?

    Warhead surfaces aren’t metal for modern warheads, they’re ablative composites or very high temperature tolerant ceramics.

    The depicted warhead in the highbay imagery (could be mockup WH / missile) has one material as the black nose, about half the length of the nose as another blue/green component, the back half of the nose as another blue/green component – with a slight decrease in half angle at the dividing point.

    There’s an evident seam between the black tip and front half of the nose cone, and seam at the angle change on the nose cone. There’s no evident seam where the nose cone fairs into the central cylinder – there could be one, the closest up warhead image is from a nose-on enough angle (image 6) that you can’t tell if there’s a seam at the nose/cylinder interface. Image 4 and 3 give better from-the-side views but are further back and might not see a seam there.

    I think there’s a seam where the cylinder meets the tail flare.

    This is not abnormal. One can do solid one piece thermal protection system outer mold lines for warheads – but it’s actually fairly unusual for that; the US practice was a separate nose tip on conical warheads, for example, with a non-ablating very high temperature ceramic to keep nose shape constant and avoid ablation inconsistencies changing the trajectory during reentry.

  48. George William Herbert (History)

    Pedram asks about the exhaust trail dissapearing.

    This is fairly normal – you see rocket exhausts for several reasons.

    At low altitude, with low expansion ratio nozzles, the exhaust stream stays together, expanding slowly over time as it travels out behind the rocket. near the nozzle, at low altitude, its’ very hot and visibly glowing. Solid motor exhausts using metals like aluminum or oxidizers like perchlorate (or both) also have white powder in the exhaust which remains visible well after it’s stopped glowing. Liquid propellant motors burning kerosene, especially fuel rich mixture ratios which help increase specific impulse, leave a black/brown smoke residue which also persists.

    At higher altitudes, some of these factors are lessened. First, high altitude nozzles expand the gases more before they leave the nozzle. That means that they’re cooler gases, and less likely to be still hot enough to glow. With less external pressure, the gases also expand out to the sides very quickly at higher altitude, so any remaining glow or powder in the exhaust stream spreads out from a relatively thin exhaust trail into a wide plume, which is much less visible against the background. The plume total volume is still about the same, but its brightness drops to near or below the ambient light levels in the atmosphere, and it becomes very hard to see from the ground.

    For example – yesterday NASA launched a Minotaur solid fuel rocket to orbit with some scientific satellites. The video is up at:
    http://www.spaceref.com/news/viewpr.html?pid=28235

    If you watch the video, the smoke trail is very clear from launch to about 3:20 into the video. Then between there and 3:35 the plume lightens and widens out very significantly, and drops near the limit of visibility from the ground even using the big telephoto lens they are using.

    There’s one additional factor which could be in play. Some rocket motors don’t use HTBD / perchlorate / metal solid rocket propellants – “high energy” rocket motors using double base propellants such as nitrocellulose/nitroglycerine plus additives like GAP or a little boron or the like have slightly better performance. They’re more expensive, and harder to make the propellants, but they also have a side effect that their exhaust has no significant visible solids in it. You can see a flame near sea level, but there’s no smoke trail.

    If the upper stage motor used a double base propellant, that would further reduce the upper stage’s visual signature…

  49. Pedram

    George: Thanks for your clarification.

    The puff dissappeared rather quickly. The time between second stage ignition and the “sudden” exahust disappearance was around 20s.

    Anyways, Mr. Najjar said the second stage proppelled the warhead to some 800 Km altitute. What conclusions can be drawn here?

  50. Azr@el (History)

    ?“You can see a flame near sea level, but there’s no smoke trail.”?

    I believe this is a misstatement; there’s a very visible exhaust trail with double base propellants, I believe this is due to the heavy mass of the products in the exhaust and their inability to disperse well in an atmosphere of light weight species such as o2 and n2. The only thing I’ve ever seen go up without are near complete burning liquid rockets, less massive exhaust products, and even these will start to form a contrail when they punch thru the upper trop and lower stratosphere layer when atmospheric conditions are conducive to contrail formation. Rockets lose their contrails somewhere in the stratosphere, ceteris paribus, much like certain high performance military jets, mig-25,31, will lose their trails in an afterburner powered vertical climb. I believe even sounding rocket and SLV rocket plumes themselves disappear when the partial pressure drops to the micron level leaving only a glow at the base of the nozzle.

  51. George William Herbert (History)

    I was simplifying somewhat. “No” smoke trail for double base propellants is an exaggeration.

    The smoke trail is not opaque, but there is a trail.

    It’s not the same as old “smoky” jet engine trails, but one might qualatatively compare them.

    From tens of kilometers away, in daylight, it would likely not be visible.

  52. George William Herbert (History)

    More image interpretation…

    There’s a hard-to-see gap between the first and second stages, with much of a flattened (not hemispherical) front bulkhead for the first stage visible in the gap. The FARS launch image “8” from the gallery shows this most clearly (you can see the gap on the right side, and the sunlight shows the shape on the left). You can see hints of this in the high bay image “2”, but the angle isn’t great.

  53. Paul (History)

    I realize this is a domain for tech-wonks, and it valuable for that reason. But one perspective I have on the DPRK test is that it can be viewed as “successful” if the goal was a political one. Technical failure, yes. Provocative and message-sending outwardly, and power consolidating inwardly – successful.

    Paul

  54. Mac (History)

    @Mehrdad

    I am not sure how you reach the assumption that test permissions come from supreme leader (and not the Supreme National Security Council for example or even the defense minister himself).

    This is a major assumption in your suggested decision model.

Pin It on Pinterest