back to article Watch SpaceX's Starship SN4 prototype accidentally self-destruct in a rocket test burn

In yet another setback for Elon Musk's beloved steel spaceship, a SpaceX Starship prototype has exploded on the pad during a rocket test burn. Starship SN4 – designed to ferry astronauts to the Moon and Mars – was undergoing a static engine fire test on Friday when, in scientific terminology, it blew the hell up. Footage of …

  1. HildyJ Silver badge
    Unhappy

    Sad

    But with the MK1, SN1, SN3, and SN4 all blowing up (SN2 was a stripped down version for pressure testing) the Mars colony dreams seem to be sinking into the ruddy sunset.

    1. Anonymous Coward
      Anonymous Coward

      Re: Sad

      Not the rocket problem but the radiation and the energy demands I think do that.

    2. Andre Carneiro

      Re: Sad

      You may be right, but I don’t think this is why.

      Elon himself said he’s expecting to go through about 20 prototypes.

      Allow scientists to fail. The fear of failure is what corrupts science, to the benefit of nobody.

      Shame, nonetheless...

  2. squirrelboy

    The video doesn't show the full story...

    The video starts too late. If you look at other videos, you will see the full chain of events. The test fire for just a few seonds, then stops. The upper and lower tanks vent for about 40 seconds then stop. Nearly a minute later the upper tank starts venting and a couple of seonds later cryogenic fluid suddenly comes pouring out of the bottom of SN4, creating the white cloud around the base (this is where the linked video starts).This happens for nearly 30 seconds before the explosion, and is clearly an massive uncontrolled leak. Shortly after the masive leak, the upper tank starts emergency venting with a second outlet. SN4 doesn't deform or collapse, so I think Scott Manly is incorrect about the weight of the upper tank crushing the lower tank. SN4 is fully intact, and doesn't deform until the explosion shockwave hits it. Looking at varous videos frame by frame, it appears the igntion point of the explosion is external to SN4: for a few frames, the wavefront apears to defom around SN4 (which was fully intact), and only after then SN4 experiences RUD.

    My guess is that the lower tank ruptured and an external ignition source triggered the explosion.

    Still I'm sure valuable information was found. This is why they do testing.

    1. Jellied Eel Silver badge

      Re: And FAED to black

      Shortly after the masive leak, the upper tank starts emergency venting with a second outlet. SN4 doesn't deform or collapse, so I think Scott Manly is incorrect about the weight of the upper tank crushing the lower tank

      I don't think that's what Scott was saying-

      https://www.youtube.com/watch?v=BCUYG5SonCY

      Slow-mo near the end seems to show venting from side, then much larger venting underneath, then ignition and the artificial mass block making it's break for orbit. Also curious if the second explosion was just that block coming back down to earth.

      Also curious about what exploded, ie comments that it was mostly CH4 & atmospheric oxygen rather than LOX.. But it's also an interesting bit of reality vs Hollywood. So fuel happily vents until it gets to an explosive concentration & finds an ignition source.. Then the big bang & pink compression wave from the explosion followed by presumably the methane buring off in a typical Hollwood fireball. Also demonstrates why it's not always easy to make gas storage explode given the pressure of the escaping gas can blow out an ignition source, as it did with the flare stack.. And also how specialists sometimes deal with gas well leaks, ie using explosives to blow out the flame.

      Spectacular videos, but somewhat to be expected during testing of a new design.

      1. Alan Brown Silver badge

        Re: And FAED to black

        "I don't think that's what Scott was saying-"

        Scott's hypothesis is that the fuelling lines broke loose - and he showed slowmo footage of the thing blasting itself into the ground when it vented methane out the top after pushing the 20 tonne mass adaptor sitting on top off at about 100km/h (which happened when the entire stack "jumped" thanks to the explosion under the base)

        ie: This was a setup/ground crew error, not a rocket/vessel failure.

        1. Jellied Eel Silver badge

          Re: And FAED to black

          Yeh, the videos showed something leaking at the base for a while before the explosion. Curious if that was both CH4 and LOX, then evaporation allowing that to get to an explosive mix. Scott highlighted the horizontal shockwave & the hemispherical shockwave, one of which probably ruptured the vessel as well as launching the mass block. I guess it'd be possible to guestimate the force required to do that as a methane jet give or take knowing bulkhead strengths.

          But not 'nominal'. Might mean snags with the defuelling process, or just something deciding to let go.. Which I guess is always a challenge working with cryogenic fluids & the kinds of heat cycling/stresses that are part of rocket science.

    2. John Brown (no body) Silver badge

      Re: The video doesn't show the full story...

      "it appears the igntion point of the explosion is external to SN4:"

      Lesson learned: Memo to all ground crew. No more sneaking around the back of the shed for a crafty fag during testing.

      1. Sorry that handle is already taken. Silver badge

        Re: The video doesn't show the full story...

        It worked for Mikhail Yangel...

        1. John Brown (no body) Silver badge

          Re: The video doesn't show the full story...

          Whoa! Facts always end up stranger than fiction! Thanks for the heads up on that.

  3. Spherical Cow Bronze badge
    Mushroom

    That's a big bang!

    In the compilation video watch the Proton M from 2013, camera 4. Start at 31:17. Wait for the shock wave to arrive.

    1. Hubert Cumberdale

      Re: That's a big bang!

      Wondered what you were going on about for a bit... but then it became clear. That must have broken a lot of windows.

      1. Louis Schreurs Bronze badge
        Mushroom

        a lot of windows.

        I didn't realise that Micros#~1t participated in those tests.......................

        1. Anonymous Coward
          Anonymous Coward

          Re: a lot of windows.

          You don't need to break those kinda windows, they do it for themselves.

  4. Anonymous Coward
    Anonymous Coward

    Think Titantic...

    It looks like they will need to divide those tanks up into compartments, enough sections, so the full weight of the stack above doesn't cause it to collapse if one section was to have a catastrophic failure/leak below. How much extra weight that will add is anyone's guess, right now. Apollo seemed to use a corrugated design in the rings, maybe that is the way forward.

    It's interesting watching all the historical footage regards the Gemini and Apollo programmes on YouTube, because you can see exactly the same empirical methods been used back then to solve problems, except now we can back it up with computer modelling, in terms of reiterating over the design.

    Makes you think too, of the calm bravery of Armstrong, Aldrin and Michael Collins, as they headed to the launch pad of Apollo 11.

    1. Anonymous Coward
      Anonymous Coward

      Re: Think Titantic...

      The Titanic reference I'm not sure about. The Titanic's problem was that it had a double bottom but not double bilges.

      It was actually the Germans who went for lots of W/T compartments and that had its effect at Jutland/Skaggerackschlacht, another occasion on which superior German technology resulted in fewer German deaths than British ones, we never learn.

      1. Alan Brown Silver badge

        Re: Think Titantic...

        "The Titanic's problem was that it had a double bottom but not double bilges."

        Bilges weren't so much of a problem so much as the "waterproof compartments" not being sealed at the top.

        As each one filled up, the bulkheads were overtopped and water fillled the adjacent compartment. If they'd been sealed it would have been swamped but stayed afloat.

        That's quite apart from the deficient crush structure White Star adopted vs P&O, in order to have the big open spaces internally and a reckless captain who treated the liners like speedboats (he'd already badly damaged Olympia off of Liverpool causing it to be dry-docked for months)

        TItanic's best chance of survival would have been a head on collision with an iceberg - it would have killed the entire crew of ~200 stokers asleep in the forward compartments but the ship would have survived just fine. On the other hand we wouldn't have SOS and all the marine rescue stuff that resulted form the loss.

  5. Fruit and Nutcase Silver badge
    Trollface

    Rapid Unscheduled Disassembly

    any relation to the "Rapid Unscheduled Deceleration" that Teslas on "Autopilot" sometimes exhibit?

    1. Methusalah

      Re: Rapid Unscheduled Disassembly

      My Gd, who plays KSP, would call that sort of event a THUD.

      As in: Terminally Hazardous Unplanned Deceleration

      1. Uncle Slacky Silver badge

        Re: Rapid Unscheduled Disassembly

        Also known as "lithobraking".

  6. Fruit and Nutcase Silver badge
    Mushroom

    Kaboom Inc

    A wholly owned subsidiary of SpaceX, for testing rocket prototypes.

  7. TheProf Silver badge
    Flame

    I couldn't help it

    The explosion looks a lot like the work of Gerry Anderson.

    How long before TB1 lands at the scene and Scott starts to organise the rescue?

  8. John Smith 19 Gold badge
    Unhappy

    Not good news, but SN5 is already being built.

    The real excitement is around SN6.

    That's expected to have an actual TPS and be orbit capable.

    Not another welding issue I hope. :-(

  9. Pete 2

    Designed to go BANG!

    > yet another setback

    Hardly. The only thing of importance that has been lost is time - and maybe 1 Raptor engine. These test bed rockets (although "rocket" is a misnomer since none of them have got off the ground¹ yet) are disposable rigs positively intended to find the weaknesses, faults and places for improvements. It is far better and much more cost-efficient to discover all these faults now than when these things have payloads or people on them.

    Experience is another word for mistakes, learned from.

    [1] in a controlled fashion

  10. pinkmouse

    I was watching live, on the NASA spacefight stream, (I only do it for the 3 hours of flarestack action you know), and to me, the commenters on the stream, and indeed Scott Manley in his latest YT vid, the explosion looks more like it started in the region of the ground support system, the pipes and cables that connected SN4 to the rest of the world. I didn't see any signs of structural collapse in SN4 at all.

  11. Paul Herber Silver badge

    Oh, sir, if there should happen to be an explosion, what do we do?

    Well, normal procedure, Lieutenant, is to jump up 200 feet into the air and scatter yourself over a wide area.

  12. beast666

    Starlink

    Is primarily a military asset.

  13. Tom 7 Silver badge

    Virgin fail last week

    any video out there?

  14. This post has been deleted by its author

  15. Mark 85 Silver badge

    No one said it, I'll do it.

    Obligatory: Rocket science is easy, it's the rockets that are hard.

  16. Anonymous Coward
    Anonymous Coward

    "an all American crew in an all American craft"

    Built by a South African with engineers from all over the world.

    I celebrate the entrepreneurship and all that, but let's cut the jingoism, shall we?

    In other words:

    — The Russians put our camera made by our German scientists and your film made by your German scientists into their satellite made by their German scientists.

    1. Uncle Slacky Silver badge

      Re: "an all American crew in an all American craft"

      Well, Elon is (also) a US citizen, so they're technically correct (which is the best kind of correct).

  17. Vulch

    Ground equipment

    Apparently a comment from Elon as he was leaving KSC last night runs "Unfortunately what we thought was going to be a minor test of a quick disconnect ended up being a big problem," so not a problem with the rocket directly.

  18. beep54
    Happy

    Ya gotta admit

    At least it was a spectacular, if short, pyrotechnics show.

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