back to article If you guessed China’s heavy lifter failed due to a liquid hydrogen turbo engine fault, well done!

China’s National Space Administration has figured out why its Long March Y2 launch went awry in July 2017. The “unsuccessful” launch, as Chinese authorities put it at the time, was China’s second attempt at achieving heavy lift capability with its new Long March 5 vehicle. The first launch of the rocket, which boasts a …

  1. Anonymous Coward

    “local structure anomaly”?

    We know what that means. See icon -->

    1. DropBear Silver badge

      Re: “local structure anomaly”?

      "local structure anomaly"...? Don't those tend to decay into a "global structure anomaly" with a very short half-life...?

    2. Michael Thibault

      Re: “local structure anomaly”?

      That would be the "complex thermal environment", then? --->

  2. Bubba Von Braun


    The fuel turbo pump lost a blade (“local structure anomaly”) that then dropped the fuel flow into the engine (“momentary decline”) causing an oxygen rich engine environment followed by rapid disassembly of the vehicle (“the loss of launch mission")

    There was no recovery from the decline as the engine was now a firework.. And who said you needed black powder to do fireworks...

    1. bombastic bob Silver badge

      Re: Translation...

      part of the problem may be the use of H2 rather than kerosene. The Saturn V first stage used kerosene but all other stages used liquid H2.

      As I recall some of the problems with using liquid H2 in the first stage has to do with the fact that it's at an extremely low temperature, which causes material problems. Metals get brittle at cryo temperatures, and lubricants "don't". It's not so bad when you're operating in a vacuum or near vacuum, at least as I understand it, but at sea level you have moisture accumulation and the engine nozzle is somewhat of a compromise since it has to operate at atmospheric pressure as well as a near vacuum, and everyplace in between.

      To get fuel into the engine at the necessary volume and pressure, you need to have a high volumetric flow turbine-powered pump. And apparently that's what broke. I think they use reaction-style turbines.

      (unfortunately this site requires javascript to view the content)

      Anyway, my understanding is "it's tricksy" and Elon avoided it in the 1st stage, deliberately. And so did NASA back in the 60's. Probably for the same reasons.

      I would guess the fuel tanks would be smaller as well, though the 1st stage would weigh quite a bit more when fully fueled, using kerosene rather than liquid H2.

      1. Mike Richards Silver badge

        Re: Translation...

        Thanks for that information.

        Having said that, both ESA with the Vulcain, and Energia with the RD-0120, cracked large LH2 motors for their first stages.

        1. Brian Morrison

          Re: Translation...

          They eventually developed them to the point where nothing physically cracked during the necessary burn time. But I do recall a Vulcain nozzle distorting and causing the changed thrust axis to push the Ariane off course and it failed to reach orbit.

          When the Russians were developing the oxygen-rich turbo-pump-exhaust closed-cycle engines they had a few failures. Apparently when they went wrong the several inch thick steel turbo pump casings burned through in a few hundred milliseconds.

          1. Dr. Mouse Silver badge

            Re: Translation...

            The part that burns the cold air that once burned a big sky bag broke. This made everything burn, which is a bad thing.

      2. Yet Another Anonymous coward Silver badge

        Re: Translation...

        But it does give you about 40% more ummph than kerosene.

        It's main disadvantage of LH2 is that you can't store the fueled rocket for very long so it isn't much use a missile. If your launch technology is really just an ICBM offshoot or is just a cover for missile work then kerosene is a better choice

        1. Gene Cash Silver badge

          Re: Translation...

          No, the main disadvantage of liquid hydrogen is IT'S HUGE. The tanks become so large, that their weight overcomes "the 40% more oomph"

          This is why first stages (Saturn V, Falcon 9, etc) use RP-1 (aka highly refined kerosene)

      3. John Smith 19 Gold badge

        "Anyway, my understanding is "it's tricksy" and Elon avoided it in the 1st stage, deliberately."

        So better watch out when he starts shopping around for a deserted tropical island (extinct volcano optional)?

      4. Faux Science Slayer

        "Perplexing Apollo Questions for NASA" at FauxScienceSlayer

        Did NASA fake the "giant leap" event to continue funding ?

        Apollo Command Module had inadequate fuel for return flight. Lander Module had inadequate fuel for landing and takeoff. NASA never had a successful robot land and return from Earth. There was no docking or air lock system on Command or Lander Modules.

        CIA has a long history of film propaganda, TruthStreamMedia >

        "Military Top Secret Hollywood Film Studio"

        1. GrumpenKraut Silver badge
          Thumb Down

          Re: "Perplexing Apollo Questions for NASA" at FauxScienceSlayer

          Spamvertizing your idiotic web site again, Joseph A Olson?

          [spamvertized document argues that moon landing was a fake]

          1. diodesign (Written by Reg staff) Silver badge

            Re: GrumpenKraut

            It's now dealt with.


            1. GrumpenKraut Silver badge
              Thumb Up

              Re: GrumpenKraut

              Thanks, much appreciated!

    2. John Smith 19 Gold badge

      "Long March 5 intended to carry the Chang'e 5" "collect..specimens..Mooon," failures..unwelcome.

      I reckon Bubba has it about right.

      Also especially galling with the Indians having gotten to Lunar orbit first.

      Note though that LH2 makes a lousy fuel for ICBM use, unlike hypergols, which served the US Titan 2 well for decades (and still fill the tanks of many of the Russian fleet).

  3. MatsSvensson


    Its all falling apart, like a Chinese


    lunar rover

    heavy lifter !

    1. Paul 129

      Re: Aaaaaaahhh....

      Once they get their quality control teams to eliminate the cheap knock off parts from Alibaba. They'll have something that we cant compete with.

  4. Pascal Monett Silver badge

    So, no new timeframe on moon launch

    I would take that as bad news. It seems that the moon mission is on hold, or at least severely set back.

    Which is contradictory when China declares that the launcher's problems have been dealt with. If that is truly the case, then China should have given a new timeframe immediately, with enthusiasm.

    But no. No more problems, and no moon launch timeframe. Those two things don't go together.

    It doesn't look good.

    1. I&I

      Re: So, no new timeframe on moon launch

      “No more problems” would be a concerning assumption in any potentially consequential engineering context.

      Leaders do that so we don’t have to.

    2. DropBear Silver badge

      Re: So, no new timeframe on moon launch

      Of course those things do go together: it's just that the first is the consequence of the second...

    3. Alistair Silver badge

      Re: So, no new timeframe on moon launch

      when China declares that the launcher's problems have been dealt with

      Presumably the expense of dealing with the launcher's problems were paid by the family of the problem?

  5. Qwertius

    I wouldn't be so hard on the Chinese. The American Space program was crap in the early years too. It also suffered big setbacks. There is even speculation that Russia may have even been the first country to lose a spaceship containing two cosmonauts back in the 1950's. In any case -- so long as the Chinese play nicely - they can visit the rabbit on the moon any time they want.

    1. phuzz Silver badge

      Or to put it another way:

      It is rocket science.

      (and the Soviets lost the first cosmonauts in space in the 1970s, not 50's)

      1. I ain't Spartacus Gold badge


        There were persistent rumours of earlier losses. Although, since stuff opened up in the 90s I'm pretty sure we'd have found out if they were actually true.

        Radio 4 did a great documentary on a bunch of Italian radio hams in the 50s and 60s. They'd got an old WWII bunker and a bunch of radio kit and were having lots of fun listening into (and recording) US and Russian space comms.

        But then they've got "other" recordings. For some reason they started faking stuff. There's a recording of a woman cosmonaut struggling to breathe (presumably g forces) and then dying - and another of a Russian crew whose retro burn has gone wrong and sent them on a one-way trip away from the Earth - as they chat to mission control before going out of radio range - and off to certain death.

        Robert Heinlein mentions a manned launch (in the 60s I think) that was announced when he was in Moscow, on holiday. Then no further announcements were made about it, and there were rumours that it had blown up. But then he was very anti-Soviet and maybe wanted to believe that, and inconsistency and bizarre attacks of secrecy in Soviet media announcements wasn't exactly uncommon...

      2. MrXavia

        Rocket science is fairly easy, rocket engineering, now that is hard!

      3. james_smith

        There's also the 1960 "Nedelin Catastrophe", where the head of the Soviet space programme and roughly 100 other personnel were killed in a launch pad explosion.

      4. phuzz Silver badge

        I've heard the "lost cosmonaut" theories, but as you point out, they're almost certainly bollocks. The USSR was surprisingly open about Komarov in Soyuz 1, and the three cosmonauts in Soyuz 11 (pretty much the only people to die in space AFAIK), so it's pretty unlikely they'd have covered up manned launches.

        I think part of the stories might have come about because during test launches the Soviet engineers would test the air-ground radios by broadcasting from the test spacecraft, so radio hams might well have picked up transmissions from spacecraft that were officially unmanned.

    2. Alan Brown Silver badge

      "The American Space program was crap in the early years too. It also suffered big setbacks."

      And they learned from them. One of the lessons being "don't trust contractors"

      From the Earth to the Moon miniseries was pretty good at covering much of this.

      One good example being the Apollo1 fire. Whilst the proximate cause of the disaster was too much velcro in a pressurised oxygen atmosphere (polyester is explosively flammable in that environment), when a capsule was torn down to see what started the fire it was found to be so shoddily built that the sparking wiring that triggered the fire was the least dangerous of the many faults which could have killed astronauts in orbit.

      Quality control is important.

  6. Speltier

    Need Better Simulation

    I'd suggest using the Kerbal Space Program.

  7. Rich 10

    Score another one for SpaceX - China is still trying to get a big rocket to the moon, while SpaceX is on the road to Mars with their first try - though the great Elon said he would not be surprised if the FH blew up 200 ft off the pad.

    1. Paul 129

      @Rich 10

      "core another one for SpaceX - China is still trying to get a big rocket to the moon, while SpaceX is on the road to Mars"

      I don't believe that the Tesla is fit for purpose .

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