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Superheavy prototype #7 explodes during tanking test

Capitalism in space: SpaceX’s Superheavy prototype #7 exploded yesterday during a tanking test in Boca Chica, Texas.

I have embedded the video of the explosion below, cued to just before it occurred.

According to Musk, the engineering teams are presently assessing damage. The booster itself appeared relatively intact afterward, though leaning slightly to one side.

At a minimum this incident will delay the orbital launch attempt, especially if booster #7 must be replaced with booster #8, already being prepped in the assembly building nearby.

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On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

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  • Ed Kelleher

    Exploded? So where are the pieces? What happened doesn’t reasonably fit any definition of explode.
    Not sure why you’d say that, but I know that what you say no longer has as much value to me. So after 36 months, I’ve discontinued my $2/monthly donation. I bought and enjoyed Pioneer and don’t begrudge the $72. Just saying. Best, Ed

  • Diane E Wilson

    The explosion was below the booster, so the booster itself did not explode. There was a shock wave, though, so the term “explosion” is close enough.

  • sippin_bourbon

    There was certainly an explosive event. Possibly an engine or plumbing giving way during the spin up test. But the entire vehicle was not destroyed, if that was your expectation.

    Way to make it all about you tho!

  • Jay

    Nice photo of the engines by Nic Asuini, looks like the bells of the Raptors survived.
    Everything is going to be pulled and inspected. I know Booster-8 is being built, I wonder if that one will be doing the orbital test while they fix up Booster-7?

  • Skunk Bucket

    From the way the nearer camera jumped, I’d be willing to use the word “explosion,” though I’m sure the shockwave was subsonic. In any case, it was definitely not what Elon & Company were hoping for.

  • Robert Pratt

    Ed, what foolishness. It was an explosion as there was a shockwave visible when it hit the various cameras you can see online. Local media reported it as an explosion as well. To claim that it’s not an “explosion” unless you can see pieces is beyond ridiculous.

  • Lee S

    @Ed Kelleher,
    Well, I’ve never agreed with pretty much any of the politics of our host, and 99% of the readers here… However I’ve tried to throw in a buck or 2… Even if literally only that. ( Payday in 2 weeks.. a buck or 2 earmarked..)
    I come for the science… Which is generally excellent, and occasionally stick around for the politics, every right wing forum needs a token leftie…
    This is the only space I know ( pun kinda intended ) where dissenting opinions are allowed without censorship or moderation, within rules that only enforce polite engagement.
    If you are dissatisfied with the content here, it would be better to explain why, rather than write a scathing comment, while flexing your book purchase.

    Bob and frenemies… Never stop doing what your doing.. well, you could all take a look at the world from a more left/environmental viewpoint, but it’s hardly likely that’s gonna happen, so I’ll keep banging my drum.. you guys will keep denying the truth I speak, and Ed will no doubt remain upset about something non of us really understand.

  • Ray Van Dune

    Not surprised the engine bells seem intact – think about the forces they are designed to handle on ascent and descent!
    But the undersurface of the booster must be on the order of 75 square meters in area, so there would have been a huge force applied to it by the explosion. And if the booster is indeed misaligned, it probably means that the very complex launch table hold-down mechanism could have been compromised, not to mention the hill of the booster itself!

  • Ed Kelleher: Sorry that you have decided to leave. I thank you however for your long time support. It was very much appreciated.

  • Skunk Bucket

    The audio has been synced with the video in this Clip. That was a definite BANG.

  • Skunk Bucket: These synchronized sound clips suggest strongly that what we are seeing is the catastrophic failure of one or more Raptor engines at the base of the booster. The booster, tower, and launchpad all seem to survive with relatively little damage.

    Whether that damage is minimal enough to allow this booster to fly is not clear. This is obviously what SpaceX engineers need to determine, even as they also pinpoint exactly what failed.

  • Tom

    Lees S .. I will publicly admit that I agree with everything you stated in your post above. So, a well earned Hat Tip to you on that.
    I am still trying to get a handle on the moment.

    Whatever happened was certainly a highly explosive event that thankfully did not occur in an area where it could have totally ripped the ship apart. Pieces of the pad went flying everywhere though. And we still do not know if any of the pressure bulkheads, the fuel plumbing and/or externally mounted components didn’t survived the event. I’m pretty sure an engine or four bit the dust though.

    I’m really curious as to what gas they were running through the system and where the spark (or metal fatigue) made its presence known. Did they have to run Oxygen instead of Nitrogen for that test?

    Ed, It is sad that you can’t recognize the real value of this web site. I’ll give you a mulligan and blame your eye doctor and teachers.

  • Cotour

    “Exploded? So where are the pieces?” (And so I am leaving)

    Why does this not make sense to me? Something apparently failed on the lower end of the rocket, and it apparently let loose, and it unexpectedly ignited and exploded.


    Is it me?

  • David Ross

    As semantic as it all is, I think we should be able to agree
    (1) there was an explosion in/under the #7
    (2) the chassis of #7 was not part of the explosion; so, #7 did not explode (although it’s certainly been rendered useless excepting for what it tells Elon as a stress-test).
    We say that Reactor Four of the VI Lenin plant at Chernobyl exploded, in fact much of the building exploded with it; we shouldn’t say “Chernobyl exploded”.
    That might be the mathematician in me however.

  • Mike Borgelt

    If it was one Raptor and the booster after inspection would have still continued flying, this might have been a good test. It’s an ill wind and all that

  • James Street

    Blowing stuff up.

    Now that’s the SpaceX we all know and love.

  • pawn

    Could someone post the source of the “tipping” finding?

    Thirty-three engines is a lot of thing having to happen in sync with obviously unknown levels of tolerance.

    I’ll be surprised if there aren’t more unexpected booms.

    I have to admit that this program is massively entertaining to this hardware engineer.

  • Ray Van Dune

    “At a minimum this incident will delay the orbital launch attempt, especially if booster #7 must be replaced with booster #8, already being prepped in the assembly building nearby.”

    Paradoxically, if there is more substantial damage to B7 than we suspect (or than can be verified in a timely manner), Elon might just go with B8, minimizing the impact on schedule. With the announcement of an SLS launch date in late August (i.e., September / October), who knows what competitive urges may be burgeoning at SpaceX?

  • Edward

    Ed Kelleher,
    An explosion need not be contained and need not have shrapnel. Thunder is the sound of an explosion due to the very rapid heating and localized pressurization of air by lightning. An explosion is a rapid decompression, often with a noise.

    However, we usually see explosions from an internal overpressure event of some kind, so we see shrapnel directly or indirectly from the damage done to the surrounding area. Your expectation is justified. In this case, there were a few items that had been thrown around and are visible in the video, so there was damage done to something, even though the explosion seems to have been a fuel-air explosion.

    I hope you stay around and continue to ask questions. Questions are an excellent way to learn new things, which presumably is why you have been coming here. (Experience drills the lessons better, but usually comes with more pain and suffering. SpaceX just had a learning experience with this explosion.).

    If this was only a tanking test and not a static fire, then the cloud that dropped from the stage looks like a seriously large leak formed suddenly. This would be a bad thing, as there should not have been any pressures large enough to cause such a leak.

    Perhaps a valve opened inadvertently, by stray command or otherwise. It looks like an engine start that went badly wrong, but if this was only tanking test, then that is not the explanation.

  • Steve Richter

    SpaceX seems to be forcing and rushing the testing. First they static fire each Raptor 2, on its own. Next test is to put all 33 on a booster and hope for the best? Could they strap a few on a standalone booster and launch that as they did the Starship last year? That would test the Raptor in actual flight, make sure the booster can be controlled and practice landing in the chopstick arms.

  • Jeff Wright

    I am an SLS guy, but I am charitable enough to say that the title should read “Booster 7 ruptures, small explosion at base.” This eliminates the vision of an N-1 type RUD. That had spherical plastic kero tanks. Had Elon went toward LOX filled composites-that would have been a real blast, so to speak.

  • @Lee S:
    Nicely put. I agree with you; I’m here for the science also. I often (very often) disagree with our kind host Bob Z’s politics, but I’m always thrilled with his excellent science reporting.

  • Steve Richter

    “… I often (very often) disagree with our kind host Bob Z’s politics, …”

    Where do you disagree? That the democrat party is not looking to shutdown the Starship rocket system? That cancel culture is not a toxic mess and blight on academic scholarship?

  • sippin_bourbon

    Steve Richter

    This was not a static fire test, though.
    It was “spin” test, regarding the start up sequence, which Musk has stated is “complex”.

    This implies that there are multiple tests and procedures involved, not just fire it, and mount it.

    However.. if I might manage a summation of this event: “Fiery, but mostly peaceful”.

    (Full sarcasm in play).

  • sippin_bourbon wrote, “However.. if I might manage a summation of this event: ‘Fiery, but mostly peaceful’”.

    LOL. That’s good, very good.

  • Diane E Wilson

    A bit of clarification for anyone actually interested. Raptor 2 has a very complex startup sequence. This test was a “spin test” for the turbines that pump fuel for the engines. Unlike most rocket engines, Raptor has separate turbines for fuel and oxidizer. The turbines run on the same fuel and oxidizer as the engines, and unlike most rocket engines, the exhaust from the turbines vents directly to the combustion chamber. (Most rocket engines have a separate exhaust for the turbines.) The net result is that even for spin tests, there will be fuel flowing into the combustion chamber.

    During the test, there was a big dump of cryogenics below the engines, and that’s what exploded. The explosion is all below the engines. Musk says he saw minimal damage in the engine compartment, but they’ll take the booster back to the high bay for complete inspection.

  • sippin_bourbon

    Thanks for the update, Ms Wilson

  • Jeff Wright

    I see-but that makes the “anomaly” as NSF puts it-worse. SLS and shuttle had the “sparklers’ to burn off LOX. Makes SpaceX look bad.

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