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Superheavy/Starship clears tower but fails at stage separation

Starship and Superheavy, having just cleared the tower
Starship and Superheavy, having just cleared the tower

In a spectacular first orbital launch attempt, SpaceX’s Superheavy and Starship successfully lifted off, clearing the tower and continuing through max-Q (maximum dynamic pressure). It then reached about 24 miles altitude when the rocket began to slowly spinn just prior to main engine cutoff and stage separation. At that point, because engine cutoff and separation had not occurred as planned, the engineering team used the flight termination system to destroy it so as to eliminate any risk to anyone on the ground.

As the announcers noted repeatedly, if the rocket simply cleared the tower they would consider this a magnificent success, considering that they had never fired Superheavy before in a real countdown. That Superheavy performed exactly as it should for almost its entire flight means SpaceX is that much closer to getting Starship into orbit than one would think at this stage of testing.

Superheavy still going strong, shortly after Max-Q

The screen capture to the right shows the rocket soon after passing Max-Q. At this point it was still flying smoothly, though if you look at the diagram in the lower left you can see that five Raptor-2 engines are no longer operating.

Shortly thereafter, at about the moment when Superheavy was supposed to shut its engines down and separate from Starship, the rocket began a slow tumble. No separation occurred, and it appeared that Superheavy was attempting to do its flip for a controlled return to the Gulf of Mexico, with Starship still attached. After waiting for about a minute more as the rocket began to lose altitude, engineers then decided it was time to destroy the rocket.

If you want to watch the live stream of this entire launch, go here.

New prototypes of both Starship and Superheavy are ready to go, but before another launch is attempted the company will have to analyze this data and make engineering changes. It also appears it will have to go through another laborious bureaucratic approval process to get its next launch license. Expect an update within days. Stay tuned for updates.

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  • mkent

    Well, that was entertaining.

    Let’s see: A very slow liftoff (is that normal?); first three, then five engines out; a subsonic Max-Q (is that normal?); a very slow attempt at stage separation (only 1/10th orbital speed — is that normal?); an apparent attempted boostback burn with the second stage still attached (definitely not normal); tumbling; and finally…kaboom!

    Definitely not ready for prime time.

  • Steve Richter

    How much result data can be gathered from an exploded rocket whose pieces are now in the Gulf? I am disappointed and losing some confidence in Elon. I think tests have to be done in an incremental pattern. Great that SpaceX is willing to gamble. But the next launch of this full stack will be ready in 6 months? Better to run a test every month. And design the test so the equipment remains intact.

  • Jeremy, Alabama

    Can’t wait for Scott Manley’s breakdown! There were obviously several engines out, visible in the various tracking camera views, and you could see flameouts shortly after liftoff and later in the flight. Maybe there was too much offset thrust for the gimballing engines to counteract. Anyway, Manley will have the answers!

  • Icepilot

    Now the real work begins for SpaceX. There seemed to be several anomalies, but most critical systems worked extremely well. What a beast! 5 engines out (?) & it’s still on it’s way. A massive success for a test flight – at least 1 critical failure past maxQ to fix, plus finding out the several support systems that need tweaking/change. Having multiple options for avoiding some of these problems is why Musk leaves the rest of the world behind. SpaceX could be ready to fly to orbit in a month or 2. Here’s hoping for less than 6. At least all that needs fixing seems within the sole purview of NASA.
    And I think they may need a bigger berm.

  • Gary H

    It will be interesting to see how the launch facilities survived.

  • GaryMike

    Failures on test flights provide information necessary to the transition to operational flights.

    SpaceX will learn more from this launch/flight/mission than if it had been a success, where none of the things that could possibly happen didn’t happen, this time.

    Certainly a successful test.

  • Chuck

    It actually resulted in as many as 8 engines out, and a pretty obvious underspeed at the expected staging time. Also, some sharp-eyed observers have noted that it APPEARS (images can be deceiving) the Superheavy interstage section may have buckled slightly.

    And, post-launch photos now show SIGNIFICANT damage in and around the launch pad. We can expect weeks of repairs/modifications/updates there.

    Still, all in all, a good test flight. Lots of data, and they got rid of an old model of the system. The upgraded next versions are already built and have been ground testing.

  • Ray Van Dune

    I suspect that during the T-40 sec hold, Elon made a command decision. They had to know that 5 or 6 engines were suspect, and Elon probably asked the team “Will it clear the tower?”

    Given a reluctant “yes” verdict by the team, he probably weighed the benefits of continuing to work on an already obsolete booster and ship, including installing multiple new engines, or clearing the way for the next units already built or building, while gathering huge amounts of data.

    And said “Okay, let her go…” Just my guess.

    Ps. By my back of the envelope figuring, it should have cleared the launch tower in 8 seconds, but instead took 10-ish, so it was down several engines from the git-go.

  • mkent

    Wow! SpaceX deliberately launched with neither a flame trench nor a water deluge system, and now I’m hearing that both people and vehicles on South Padre Island were hit by debris. The critics were right. This launch should never have occurred.

  • Ray Van Dune

    I forgot to add that it will be interesting to know whether the rocket disintegrated due to aerodynamic forces, or was destroyed by the FTS.

    It isn’t clear to me that the control team CAN manually trigger the FTS even if they want to! The rocket seemed clearly out of control for quite a while before it actually exploded!

  • Ray Van Dune: I have no direct information, but I am fairly sure that the FTS system destroyed the rocket. The delay could have simply been to make sure it was over water and no pieces could possibly end up on land. We have seen the same thing on several other failed launches by other rocket companies in recent years.

  • MDN

    IMHO this test was a spectacular success with an eye toward a Man Rated StarShip. I say this because Starship has no escape mechanism, so proving the ability to sustain multiple booster engine failures (at least one an obviously explosive disassembly event while near maximum vehicle stress) without suffering a catastrophic loss of the entire vehicle a la Challenger is an enormously impressive accomplishment. And to sustain reasonably controlled flight with a cascade of 6 engine failures only furthers the point. No, they did not successfully achieve stage separation after this point, but presuming they had it is easy to envision a manned StarShip surviving such a mishap and being able to achieve a boost back return to base safely if ever is necessary in the future.

    That said, it looks like there are a number of gremlins to chase and Gary H is right, assessing the impact on Stage Zero is top of the list I bet. To my eye there was A LOT of debris flying around and they probably need a fair bit more work in this regard.

    I went to Cal Poly San Luis Obispo back in the day when California had great schools and SpaceX embodies their motto of “Learn by Doing” better than any company on earth. So congratulations to them for the successes achieved so far, and here’s to building on them soon!


    Steve Rictor… If you don’t push hard in a test and only test for success, what have you learned in the test? Not much is the answer. This was a hugely successful test. Did far better than expected. Failures? In science there are no failed experiments, only unexpected results. You learn, you fix/improve then then you push again. I would never bet against Elon Musk. An amazing morning.

  • Jay

    Yes it does look like more than five engines were out. Watching the SpaceX feed with the engine status at the bottom left corner showed five engines out, then six, then back to five again. I saw a couple more engines that looked to be off verses the status, but maybe they were throttled down?
    Spectacular launch none the less.

  • markedup2

    I’m hearing that both people and vehicles on South Padre Island were hit by debris.

    “hearing” from where? We can has hypertext; just provide the link in the first place.

    South Padre is about 11 miles away. I can see something falling there, but blasting out from the launch pad due to a lack of trenching and suppression doesn’t seem reasonable.

  • James Street

    It’s impressive that that massive rocket took the stress of going 1,800 km/h while doing flips.

  • Trent Castanaveras

    During the Tim Dodd webcast while they were still outside discussing launch, the cloud from the launch moved over South Padre Island and dropped sand on them. They discuss it at length starting at 2:13:00 or so.

    Haven’t found other references to more substantial debris fall elsewhere. Yet.

  • Trent Castanaveras
  • pawn

    The pic linked above looks like a very large bomb went off which it kind of did.

    I’ve been waiting for this. Sadly.

    Elon has been pretty cavalier about a number of things at the BC facility.

    I bet NASA is freaking out right now that they let him build such a white elephant next to the Pad.

  • sippin_bourbon

    The “debris” that Tim Dodd reported was just sand. It probably kicked up a lot without a water system running.

    Still. I have been in sandstorms where I could not see my hand if I extended my arm. That was nothing.

    Where are the reports of people hit by debris? I am not seeing any. A dusting of sand does not count.

  • sippin_bourbon

    Apparently NASASpaceFlight decided to leave a minivan with the camera…

    Someone on reddit is saying this was 400 meters from the OLM.
    I am thinking.. why would you leave that there….

  • Richard M

    Elon has been pretty cavalier about a number of things at the BC facility.

    He admitted back in October 2020 that the decision to forego a flame trench “could turn out to be a mistake.” I gather they had done a lot of modeling that showed that perhaps this could be doable. I think the problem is not just the cost of it, but the difficulty and regulatory hurdles of doing one in a protected wetland where the water table is basically right at the surface. As Doug Messier (who sometimes comments here) noted in a tweet to Eric Berger an hour ago, “Getting approval for that could take years. And the Army Corps of Engineers might say no. It’s also possible that FAA could not have issued a finding of no significant impact if SpaceX had included plans for one.”

    Downthread, it was also pointed out that . . . SpaceX *did*, in fact, apply for a flame trench of a sort but then dropped it because the Corps of Engineers permitting process was going to take too long and/or interfere with getting the FAA FONSI. See for example the “flame duct” depicted here in April 2017 (at page 3):

    In one sense, Messier is right that SpaceX’s strategy did pay off: they ditched the flame duct and by doing so they moved fast and they found a way around having to do another time consuming and costly EIS. That process allowed them to use the site for a massively more powerful rocket than they initially got approval for. And they got a launch off! But if evaluation of the launch pad leads them to conclude that a duct or trench really *is* necessary, it might have proved to be a more limited victory than they hoped for, especially if it turns out that NASA insists that the LC-39A Stage Zero have a trench/duct and other additional protective remediations. I am unclear on what the environmental regulations allow them to do down there.

    We’ll just have to wait and see.

  • sippin_bourbon

    For anyone who follows the space program and is familiar with how SpaceX builds and tests, this was a successful test to get date and proceed forward. Failure as part of the learning process.

    I am seeing glimpses around the web of people trashing Elon because of this. I laugh every time.

  • It appears from the SpaceX feed that Starship failed to separate at the designated time, and as fuel burned off in SuperHeavy, the center-of-gravity moved forward along the thrust axis until the stack became uncontrollable. Curious if Starship could have made orbit with SuperHeavy missing a significant percentage of thrust. On the other hand, the booster was lightly loaded.

    NASA still has bragging rights, but only just.

  • Darwin Teague

    Several boosters and Starships failed before they got the vertical landings perfected. This is the same process.

  • pzatchok

    I predict 6 launches at best until a fully successful orbital launch. 5 more to go.

    How many failures did they have with the Falcon 9 before total success?

  • Richard M

    How many failures did they have with the Falcon 9 before total success?

    3 failures.

    Eric Berger’s LIFTOFF does a wonderful job of telling that story. Probably shaved years off Elon’s life expectancy.

  • Richard M: Those three failures refer to the initial effort to reach orbit. We should also consider the additional later failures to recover the first stage to get a sense of how many Starship/Superheavy launches will be required to achieve this target.

    Going by memory (which is certainly wrong), I think SpaceX had about a half dozen attempts to land the first stage before success. This does not include the Grasshopper tests, only the flights where the booster attempted a landing on land or on a drone ship after a successful launch.

    I think we will likely not get an entirely successful reusable Starship/Superheavy for at least a dozen launches, at best.

  • However, I also think Starship will reach orbit land successfully before then.

  • John

    Holy moly, they lit the fires and kicked the ground facilities’ &#$!& !

  • Jeff Wright

    You buy cheap-you get cheap.

    Elon just needs to watch a pick-me-up sports film-like WE ARE MARSHALL.

    SLS +1
    Starship -1

  • Shaun

    This was a huge success for a first test flight. They will undoubtedly have a treasure trove of data to go over and will be able to use that data to improve future iterations. I definitely expect to see more explosions but the way SpaceX does it it makes sense. So awesome to see rapid testing and iteration. That’s how you get things done. Such an awe inspiring launch.

  • Shaun

    Can anyone dispute the significance of this flight? Never been done before. Not even close.

  • Shaun

    I actually got to get a new junior engineer onto the topic when we watched the launch live this morning. He had no idea. When SpaceX (presumably) self detonated, it was a great source of discussion. What are your expectations from a flight test? In all cases it’s to figure out what vehicle is capable of and establish a flight envelope. Beyond that, how do you expand that flight envelope? We’re seeing it in real time and it’s amazing. Especially with the MOST powerful rocket ever to launch. This is historical and begs a ton of time and attention.

  • sippin_bourbon

    My questions about this boil down to the Raptors.
    Elon has stated that they melted Raptor after Raptor on test stands.
    I assume the three that failed at or before lift off was a start sequence problem, which is a complex problem.
    But the additional failures and flame outs surprised me.

    I am all for redundancy. I understand the idea that loss of one (or a few) can be covered by a longer burn.
    But it still seemed like a high rate of failure.

  • Shaun


    Completely agree. You could visually see the engines failing in time with the diagram that SpaceX displayed in the stream. Seemed pretty dramatic to me. Almost like like watching fireworks off the tail end as each one flamed out. Guess we’ll have to wait for SpaceX to give an official explanation. Until then we can only guess.

  • Jason Lewis

    I am VERY concerned that the US Fish and Wildlife Service will object to further launch permits due to the debris caused by this initial launch. Even if they remedy the technical problems, this could still haunt them.

  • Edward

    They promised excitement, and they delivered. A little more than I had hoped, but it could have been even more.

    Robert wrote: “That Superheavy performed exactly as it should for almost its entire flight means SpaceX is that much closer to getting Starship into orbit than one would think at this stage of testing.

    “[E]xactly as it should” may be an exaggeration. Five engines out means that the performance was suboptimal, and it showed that more development is needed. As a flight development test for the booster, it was exquisite. It is unfortunate that the upper stage did not get an opportunity to produce similar flight results.

    mkent asked; “a subsonic Max-Q (is that normal?)

    I have seen other rockets go through Max-Q at subsonic speeds. Whether this is normal for Starship is a good question that we will learn the answer to during future test flights.

    Definitely not ready for prime time.

    True, but then it is only a development test flight (not mkent). Not everyone commenting on this thread remember that. As the announcers noted, the test was pared way back from normal operations in order to concentrate on the portions that SpaceX wanted to learn more about, lessons that can only be learned through flight testing.

    Steve Richter asked: “How much result data can be gathered from an exploded rocket whose pieces are now in the Gulf?

    Apparently, you would be surprised. Test items are instrumented to the gills in order to get as much information as possible. The data collected is sent back as telemetry so that it is available for analysis. Either way, both units were going to end up at the bottom of the ocean and not recovered.

    In addition, assembly records and other ground-test records are kept, along with photographs of final assemblies.

    Records such as these are why Virgin Orbit was able to determine why its last flight failed.

    Better to run a test every month. And design the test so the equipment remains intact.

    True, but flight test of rockets does not always go this well. In fact, it wasn’t until recently that any part of a large rocket could be recovered intact, so rocket flight testing had to evolve in order to determine failures without recovering any of the rocket. Even failed operational flights are examined in this way.

    GaryMike noted: “SpaceX will learn more from this launch/flight/mission than if it had been a success, where none of the things that could possibly happen didn’t happen, this time.

    The Apollo 4 test flight of the Saturn V worked too well, and the engineers didn’t learn as much as they had hoped. The next test, Apollo 6, did not go as well, and the engineers learned a lot! The controllers learned a lot, too, because they have several problems to overcome. It had looked like it might not be a success, but the controllers pulled victory from the jaws of defeat.

    Ray Van Dune noted: “It isn’t clear to me that the control team CAN manually trigger the FTS even if they want to! The rocket seemed clearly out of control for quite a while before it actually exploded!

    A manual self destruct command is required for any launch. If the rocket does not decide to terminate, then the range safety officer always can.

    Robert has a point that the rocket should be destroyed while its debris will fall in a safe area, as winds can (and has in past failures) blow debris back to land. However, the delay could also have been to allow for additional telemetry so that the failure can be successfully analyzed. As long as the debris will fall in safe areas, they don’t have to rush the self destruct.

    James Street wrote: “It’s impressive that that massive rocket took the stress of going 1,800 km/h while doing flips.

    Please keep in mind that Falcon 9 does this as a routine for burn back, and that Super Heavy is also supposed to do this at similar altitudes. I suppose that doing it with 1,500 tons of Starship still on top could be impressive.

    Shaun asked: “What are your expectations from a flight test?

    It depends upon the test. By the time we get to qualification or acceptance testing, the thing had better work pretty well. For development testing, I want to know what worked and why as well as what didn’t work and why. During development testing, failure is an option.


    Darwin Teague summarized it well.

  • sippin_bourbon: If I was an engineer, which I am not, my first thought in connection with those Raptor-2 failures during launch would be vibrations and stress. No one has ever launched so many engines this powerful packed together so tightly. We must expect things to happen in ways unexpected.

    I also think of the pogo oscillations during the second Saturn-5 test launch in April 1968. The rocket developed an unexpected resonance along its entire length that tore one panel off and would have injured any astronaut onboard. Engineers found that by accident the natural resonance of the engines had matched the natural resonance of the rocket. They had to add shock absorbers to dampen the effect.

    I wonder if this kind of thing is now being considered by engineers at SpaceX.

  • pawn

    I haven’t hear it mentioned but I suspect there was a major leak at the booster QD. There seems to be a lot of vapor pouring out of one side of the booster near the aft end and it looks like it ignites when it gets down into the engine plumes.

    I did hear something about the service mast door not closing properly and there being damage inside the mast or whatever they call it now.

    I wonder now many times they test cycled the disconnect.

    Both SLS and SS went with hydraulically powered service mast doors in lieu of the tried and true drop weights.

  • pawn

    Well there a bunch of Raptors at the bottom of the GOM. I wonder who will be the first to bring one back. Quite a museum piece let alone a collectors item if they do.

  • Chris

    I was impressed with the control system that seemed to allow the flight to get as far as it did with what looked to be several engines out or worse going in and out. Also toward the end, the control system seemed to try to control the full 390ft assembly when problems seemed to get to the critical point – requiring (FTS) destruction. To me this was impressive.

  • Alex Andrite

    42 ?

    Skipped them all, sorry folks.
    Will read later, perhaps.

    I enjoyed the TOTAL launch.

  • People forget …

    … how much flight hardware ended up at the bottom of the Atlantic off Cape Canaveral before John Glenn rode some into orbit.

    … that the reason Gemini 6 and Gemini 7 performed their rendezvous was because the original target vehicle for Gemini 6 had to be destroyed on the way up? And that was not the only time that had to be done with such vehicles?.

    … that Neil Armstrong was almost killed TWICE before he got to step that one small step.

    … that the problem with smooth test flights, is that you don’t always find out what can kill you before it does … after Gemini 4, everyone thought that spacewalking was a cinch … until Gemini 9 and how it almost killed Gene Cernan, and exhausted astronauts on Gemini 10 and 11, before Aldrin et. al finally got it right on Gemini 12.

  • Max

    I hesitate to comment because this is outside my Bailywick, no expertise at all.

    The one thing that kept going through my mind as I watch the engines cut out for separation, (Except for one) relight then cut out again… That there’s no way the clamps will release when one of engines was still lit and pointed or outgassing in the wrong direction! causing the rocket to tumble.
    Stabilizing Jets on the side of the rocket were firing to correct, but could not control the misfiring, possibly heavily damaged engine that would not shut off.

    Have you ever tried to release clamps on any mechanical device when under a load, or under torque?
    As long as there was thrust perpendicular to the releasing mechanisms, there’s no way starship could be released without ripping something apart.
    Explosive bolts, as a fail safe, May release starship but not without consequences. I’ve never seen a separation while under thrust, I’m sure there are safety protocols to prevent separation for any reason, if expected conditions (near freefall) aren’t perfect. (within specifications)

    There was also a flame hundreds of feet from the rocket that appeared to be fuel burning from an air fuel mixture with the atmosphere, not intentional. A different malfunction, probably a severed fuel line.

    With so many engines not working, the other engines will not only have to compensate, but redirect their thrust load.
    I didn’t see anything break off, but the stress was considerable.

  • Max

    Went back and watched it a few more times.
    Near 30 seconds in the lunch there is a flash and a bright red spot appear on the side of the booster accompanied by pieces flying through the air that I assumed was ice.
    Close up of the engines shows six of them non-functioning, the sensors show five.
    Outside camera showed a flame perpendicular to the rocket that shouldn’t be there.
    Others are posting their analysis, they also note the engine malfunction preventing separation.
    He also notes that the central motors are needed for landing the booster. Too bad we won’t find out if it was critical or not.

  • Steve Richter

    Can all the concrete which came loose on the launch pad be replaced with steel?

    If it turns out that parts of the rocket were damaged by the blast and flying debris then I do not see how this flight advanced the ball much. SpaceX needs to test that all components of the system work together. But if components are damaged by concrete missiles, you are not giving the system a chance to actually operate.

    Very discouraging to read that there is no flame trench because of the regulatory requirements and denials. So important that the country has a President with the brains and decency who can step in and clear the way for a company like SpaceX which is working to do something great.

    Will the new KSC launch pad be ready soon? Hope SpaceX has enough funds and engineers to work full time on both Boca and KSC.

  • Richard M

    Hello Bob,

    “Those three failures refer to the initial effort to reach orbit.”

    My apologies! I realize now that I carelessly read Pzatchok’s question to say “Falcon 1” instead of Falcon 9! Falcon 9 of course reached orbit on its very first attempt in 2010. But then it is also true that this was only possible because of what SpaceX engineers learned from failing with Falcon 1.

    As to your point about Raptor failures on yesterday’s launch being attributable to clustered engine vibrations, I do increasingly suspect we are going to find that the engine failures were mostly inflicted by “extrinsic” causes rather than something intrinsic to the Raptor 2’s themselves (which after all have racked up hundreds of hours of successful test burns at McGregor). Not just vibrations or shock from the combined engine cluster, but probably also shock and debris impacts from liftoff dynamics at Stage Zero – I mean, it dug one heck of a crater there! That maybe on a better designed Stage Zero, Booster 7 could have got Starship successfully to an orbital insertion trajectory. If so, I think the hardest rethinking is going to have to go into Stage Zero rather than the rocket itself.

  • Richard M

    “… that the problem with smooth test flights, is that you don’t always find out what can kill you before it does … ”

    True. NASA ended up learning far more about Saturn V’s flaws from the near disastrous Apollo 6 test flight than it did the unexceptional Apollo 4 flight six months before. Without those fixes, Apollo 8 does not succeed. Frank Borman would have had to pull the abort handle by Max Q.

  • Ray Van Dune

    I hope SpaceX is hiring a diving company to salvage as many engines as possible. I suspect the engine-out problem is not Raptor unreliability, but being damaged by high-velocity launchpad debris.

    As I said early in the thread, the decision to launch was probably a tough call by Elon, but probably the right one.

  • David K

    @“Ray Van Dune” – I don’t think they care about recovering those engines except for autopsy purposes. They were an old design and sitting out in the weather for a while.

    They are not trying to create a ship, but a shipyard. The biggest concern is damage to the pad.

  • Jerry Greenwood

    A flame deflector below stage zero may be in the offing. I suspect the shrapnel from the tons of exploding concrete under the launch pad might have contributed to some of those engine issues. From the limited views I’ve seen so far it’s all gone.

  • Jerry Greenwood

    NASA’s B-57 was filming the whole thing. I wonder if they will release it.

  • Richard M

    Uh…OK. We’re getting much better imagery of the crater underneath the OLM today and…dear God. It is a wonder the thing is even standing right now.

    Zack Golden of CSI Starbase: “OMFG. This is significantly worse than I first realized. That is MAJOR foundation damage. I can’t even imagine how this can be repaired. It’s a miracle the propellant lines weren’t ruptured. This seriously breaks my heart.”

    Some serious rethinking is needed on the OLM.

  • Richard M: Seems to me from that image that SpaceX has simply gotten a head start on digging that flame trench. Rather than hire heavy equipment to dig it out, it used Superheavy to do the digging.

    And before anyone takes this seriously, I am joking.

  • Jerry Greenwood

    Just looked at the link from Richard M. That hole is down to water level but stage zero foundation pilings seem to have held up, sort of. I’ll be watching for the flyby photos to see what was damaged in the frag zone.

  • All:

    Has anyone heard anything about Starship? I just heard that it hit the water intact. Can this be true?

  • Andrew_W

    “I just heard that it hit the water intact.”
    I gotta ask, what source?

  • Andrew_W: I don’t have a reliable one. This is a rumor I heard that I’d like confirmed by a real source.

  • Edward_2

    Lots of armchair rocket scientists pontificating.

    Elon Musk’s SpaceX has done what no on else has done – land rockets on its tail like a 1950’s SciFi movie.

    Elon Musk is a modern day Howard Hughes – a rich guy who gets it done.

  • Edward

    Scott Manley released his video analyzing the flight. It contains quite a bit of speculation, however: (10 minutes)

    I’m sure that there is a whole lot of learning to be done from this flight. They had a bunch of problems that we could see, and who-knows how many others that we couldn’t.

    I’ve never seen a separation while under thrust …

    You may be interested, some of the Soviet/Russian rockets separate before thrust is completely gone from the previous stage. It allows them to fire the next stage without the propellants forming bubbles from the freefall conditions. It is at least one reason why they have those gaps in some of their interstage sections, as it allows the next stage thrust gasses a pathway out.

    Many rockets stop the previous stage’s engines before separation, which required some sort of propellant settling thrust before the next stage can successfully be ignited. Usually this is done with tiny rockets on the next stage. Here is an example (1 minute):

    Jerry Greenwood wrote: “I suspect the shrapnel from the tons of exploding concrete under the launch pad might have contributed to some of those engine issues. From the limited views I’ve seen so far it’s all gone.

    I read somewhere that Musk had described the exhaust from Super Heavy as the world’s largest blowtorch. Now we see what that can do.

    That hole in the base of the pad is impressive. Twice the blowtorch gives us this, rather than the light damage after the half-thrust static fire test. More lessons learned. I will be interested to know whether they decide the engine-out problems were due to pad debris, sonic reflections from the concrete, other problems, or a combination of them.

    Robert Zimmerman,
    I doubt that the second explosion that we saw was anything other than Starship. Its flight would also have to be terminated, guaranteeing that it would not light any engines and fly into any unauthorized debris zones. I will remain skeptical about that report, unless it is definitely confirmed.

    My first guess is that the report you heard was the result of a game of “telephone,” where someone speculated something and others took it as fact.

  • Edward: You are right. I should have watched the video again. There are two very clear explosions at self-destruct. One was certainly Superheavy, the other likely Starship.

    I had sensed that rumor was false. You have helped confirm this.

  • Jerry Greenwood

    Concrete exposed to high temperatures explodes. Actually the water trapped within turns to steam and expands by 1700 times. It has to go somewhere. KABOOM. SpaceX engineers are well aware of this and knew this damage would occur although maybe not to this extent. It’s a trade off vs regulatory hurdles that may have been insurmountable. Time is a major factor influencing their decisions. This is prototyping after all. Lessons learned will be applied to the facility at The Cape where they will have much more room and slightly more elevation.

  • Jerry Greenwood: Musk tweeted today about the concrete damage. I have added that tweet to today’s quick links.

  • john hare

    Robert Zimmerman
    April 21, 2023 at 11:06 am
    Richard M: Seems to me from that image that SpaceX has simply gotten a head start on digging that flame trench. Rather than hire heavy equipment to dig it out, it used Superheavy to do the digging.

    And before anyone takes this seriously, I am joking.

    I think you might be joking about something that could be quite real. Can’t get a flame trench permit, but one accidentally appeared when the rocket was more destructive than we thought. We’re going to have to live with it until the work load slows down enough that we have time to pour more concrete.

  • Edward

    Jerry Greenwood noted: “Concrete exposed to high temperatures explodes. Actually the water trapped within turns to steam and expands by 1700 times. It has to go somewhere. KABOOM. SpaceX engineers are well aware of this and knew this damage would occur although maybe not to this extent. It’s a trade off vs regulatory hurdles that may have been insurmountable. Time is a major factor influencing their decisions. This is prototyping after all. Lessons learned will be applied to the facility at The Cape where they will have much more room and slightly more elevation.

    Musk’s tweet referred to “Fondag,” which is a type of concrete SpaceX had come across that they thought would be resistant enough to this kind of damage to survive the launch. Reasonably well, at least.

    Fondag is a pre-blended, high strength, heat resistant concrete designed for heavy industrial applications. [Emphasis mine]

    SpaceX had planned to use Fondag after the damage that happened during the half-thrust static fire test. This test gave them some confidence that it would be close to sufficient. This is what testing is all about, the determination as to whether what we think is true is actually true. Fondag was the observation, the hypothesis was that it would be close to sufficient, but the test proved them wrong. (“Feynman on Scientific Method” 10 minutes)

    This scientific method is why there is never a consensus in science. If the test proves the hypothesis wrong then it is wrong. If there is no test, then it has not been proved right, no matter what the consensus of scientists says. When a consensus is determining The Science, then The Science is broken. Discovering what is right is very, very difficult. There have been a couple of Nobel Prizes in science given out for science that turned out to be wrong, which was not the fault of the scientists receiving the prize. Keep in mind that science is never settled. The Science may be settled, especially by consensus, but that is not real science.

  • Steve Richter

    Notice how no one is pointing blame for this launch failure at Biden and the democrat power structure. I take it as evidence that people are increasingly terrified of thinking clearly and speaking their mind. What we learned from this launch is that the rocket system will work. The fuel system works, the engines are awesome. They gimbal well and control the rocket even as the system is failing. Structurally, the rocket is solid. Only the launch pad gets destroyed and causes too much damage to the booster.

    The reason to blame Biden is it is his admin which blocked SpaceX from continuing its frequent and incremental test cadence. And it is his admin which has blocked SpaceX from considering a flame trench. ( how is environment damage from digging a trench any worse that the mayhem from this launch?) If SpaceX had been allowed to test as they deemed necessary they could have been sending up booster launch and recover flights the last 2 years. Those booster flight tests would have exposed the relative weakness of the launch pad. The engineers could have already been experimenting with different pad materials and designs, finding out what worked best. That way, once yesterday came the launch pad problems could have been worked out and the country would have seen a spectacular success, boosting American prestige throughout the world.

  • Steve Richter: Very well said.

    Let me sum up the policy of the Biden administration and the federal government in one short phrase: They wish to deny freedom to Americans to follow their dreams. And at the same time they wish to exercise raw brutal power on everyone.

    It is as simple as that.

  • Edward

    Now that 72 hours have passed, we may be getting some real news and analysis about what happened. We have already heard that Starship bent while climbing, but that has been debunked. We have heard that Starship hit the ocean in one piece, rather than being exploded for safety reasons. We have heard a lot of things that turned out to be bogus. So, what do we really know about the launch?

    This isn’t knowledge, but I have concluded that the reason that SpaceX’s primary goal was to clear the launchpad is because they had wanted to learn as much as they could about how the pad would hold up. Had Starship not cleared the pad, it would be difficult to know what pad damage came from the engine thrust and what damage came from a pad explosion of the rocket. Since it cleared the pad nicely, no one has to worry about making that distinction. This may not have been a successful failure but a complete success with a failure of a relatively inconsequential secondary part of the experiment.

    Pictures have shown us that the pad didn’t hold up well. It looks like Musk was right that it may have been a mistake to not build flame deflection. Huge chunks of the concrete from the base were seen flying hundreds of feet into the air and large splashes were seen in the ocean, a few hundred feet to the east. The pad was heavily damaged, and we still don’t know whether the launch mount portion has to be rebuilt. I think that the real test was to determine whether a flame trench was needed or whether the booster could survive without one. The booster did survive without one, but the current pad design is insufficient for rapid reuse.

    One YouTube channel, TheSpaceBucket* has a video about launch pads and flame deflectors. It may be worth viewing: (8 minutes)

    Since huge chunks of concrete had been thrown high into the air, it is very possible that other chunks of concrete had damaged some of the boosters engines.

    I am a bit disappointed that the performance of the Starship section of the rocket is limited largely to the boost phase of launch, rather than gaining some information about its own performance at altitude. It was clear that the booster had not given enough altitude and speed for Starship to reach orbital velocity and complete its mission. However, there may yet be data that can inform the engineers for future iterations.

    It is good that the booster was able to perform up to the separation point. Future boosters should benefit from this launch. No wonder the SpaceX employee crowd was so excited even thought the flight had to be terminated early.

    The coming weeks should be full of additional news about what happened, what went wrong, what went right, how well the booster handled the disintegrating situation, and what the future will be for the launch pad — “stage zero.”
    * TheSpaceBucket channel does not have the kind of presentation that I want, as the script seems to be read by a computer. However, their information seems to make sense to me, so it is one of the few space video channels that I view.

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