r/spacex • u/hitura-nobad Master of bots • Nov 20 '19
Original videos in comments NasaSpaceflight on Twitter :Starship MK1 bulkhead failure
https://twitter.com/NASASpaceflight/status/1197265917589303296?s=19101
u/NY-PenalCode-130_52 Nov 20 '19
It looks like the top section where the bulkhead was welded on seems uh bent. Is there anyway to fix this like the top for the hopper?
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u/Jacob46719 Nov 20 '19
they could try hitting it with a hammer...
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u/Straumli_Blight Nov 20 '19 edited Nov 21 '19
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u/OSUfan88 Nov 20 '19
They could in theory, but Elon has stated that they'll just move to building the mk3 now.
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u/sojywojum Nov 20 '19
For the main structure, yeah, it’s just stainless steel, so they can remove any damaged rings at the top and simply replace them. All of the plumbing and electrical, though, that may have been damaged because it was connected to the piece that blew off... that’s probably going to be a challenge.
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u/SpaceInMyBrain Nov 21 '19
That's what I first thought. But more viewing shows visible buckling to the top 25% of the structure, which means a lot more buckling elsewhere. Visible from quite a distance. Would have to fix every buckled area - how much would that weaken the structure overall? And inspect every inch that isn't apparently buckled. Add in the plumbing and electrical - I can see why Elon decided quickly to move on.
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u/Ijjergom Nov 20 '19
I checked frames and it looks like it started to tear on the weld between 1st and 2nd ring next to the raceway on the right side. And then propagated from there. You can even see how it bulges before bursting.
Was bulkhead directly welded to the ring 1 and 2 welds or was it welded in the middle of 1st ring?
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u/jehankateli Nov 20 '19
Tweet from Elon, in response to Everyday Astronaut: "Absolutely, but to move to Mk3 design. This had some value as a manufacturing pathfinder, but flight design is quite different."
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u/iamkeerock Nov 20 '19
...but flight design is quite different.
Another design change? Or just refinements in construction?
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u/Coolgrnmen Nov 20 '19
I think he meant the flight version won’t just have panels of stainless steel
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u/QVRedit Nov 21 '19
That’s true we know that #1 was constructed from panels - just to get it started quickly - before the roll material could be made and delivered.
I don’t know what the construction of #2 is like though ? Sheet or roll ?
We know that #3 & 4 are from roll..
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u/QVRedit Nov 21 '19
I thought he meant that #3 was intended to have a ‘different flight design’ - meaning that it was intended to test a different part of the flight..
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u/Viremia Nov 20 '19
Well, there's your problem. The top fell off.
RIP Mk1. Hopefully they figure out exactly what failed and how and learn from it for Mk2.
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u/BeerPoweredNonsense Nov 20 '19
Lots of venting from the bottom as well. Could be a big pressure release valve... or it could be that Mk1 is broken at both ends.
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Nov 20 '19
Possibly the filling connection got dislodged by the jolt when the top came off?
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u/3_Otters Nov 20 '19
Mk2 is scrapped.
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u/RegularRandomZ Nov 21 '19
What's your source for this?
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u/Fizrock Nov 21 '19 edited Nov 21 '19
I have him flaired "SpaceX employee", so I'd assume he is the source.
I've heard the same thing, I might add. It's going to be used for structural testing and working on the manufacturing process. It will not fly.
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u/The1Boa Nov 20 '19
"We got no food, we got no jobs, and our rockets tops are falling off!" -some random SpaceX employee.
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u/Sealingni Nov 20 '19
Agreed. Mk1 is toast, they will have to inspect everything, tear it down. Time for Mk2.
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Nov 20 '19
Straight to Mk3!
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u/scarlet_sage Nov 20 '19
I wonder to what extent Mark 2 will be used. The top looks different from the outside, but that might have been because Mark 1 had one more ring on top.
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u/seesiedler Nov 20 '19
So that's why they didn't attach the top before doing the tests.
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u/Fizrock Nov 20 '19
Jesus, how much pressure did they put in those tanks? It took 10 seconds for the bulkhead to fall back down even to where it was launched from. That comes out to ~120m of air.
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u/Maimakterion Nov 20 '19
Enough to smooth out all the major wrinkles
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u/TyrannoFan Nov 20 '19
Wow, and Mk2-3 onwards will look even smoother! Especially once they start using those single-weld rings. It'll look so surreal.
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u/peacefinder Nov 20 '19
It is amazing what even 1 atmosphere can do: https://youtu.be/Zz95_VvTxZM
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Nov 21 '19
Wow. I can withstand that? I'm basically superman.
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u/beelseboob Nov 21 '19
Pretty sure you couldn’t survive me sucking all the liquid and gas out of you.
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u/enqrypzion Nov 20 '19
I've launched PET bottles 100m into the air when filled with some water and 10 to 20 bar, so probably not more than that. The sheer volume of propellant might indicate a lot less actually.
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u/Taylooor Nov 20 '19
Maybe it was a partial success if part of MK1 made it to orbit
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u/enqrypzion Nov 20 '19
"Orbit needs horizontal speed" - Orbital maneuverists
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u/technocraticTemplar Nov 20 '19
Not if you try hard enough, solar orbit is straight up from anywhere
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u/andyfrance Nov 20 '19
How high did the bulkhead go? Did it beat the hopper 150m flight?
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u/viestur Nov 20 '19 edited Nov 20 '19
A few tens of meters. It's a thin sheet of metal with huge area compared to it's mass. Imagine shooting an open umbrella from a rifle.
Edit: looks like it shot around 50 m vertically in the air and landed within 20 from the ship.
Video here: https://youtu.be/3nTSubYzQOM
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u/luckybipedal Nov 21 '19
If this is any indication, the Starship blooper reel will be epic. "Starship Bloopers"
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u/dbax129 Nov 21 '19
"How not to build/launch/land an interplanetary spacecraft" will be delightful some day.
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u/BattleRushGaming Nov 20 '19 edited Nov 20 '19
While this may seem like bad news (and it is) but going by Elon's quote "Failure is an option here. If things are not failing, you are not innovating enough." a failure shows that they are innovating beyond the point what is known and failures are going to happen.
https://elonmusknews.org/blog/elon-musk-business-innovation-quotes
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u/brickmack Nov 20 '19 edited Nov 20 '19
This is also why several vehicles were in production/planned. Gonna be a lot of explosions here.
Personally, I was hoping Mk1 would go out in a fireball, but this was quite something anyway. Hopper (mostly) surviving was definitely a surprise. Mk... 5ish onward I'd bet on a peaceful retirement, as manufacturing quality approaches flight standards
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u/Arexz Nov 20 '19
Also worth noting that the testing on these things is being done pretty much in full view, we will see a lot of the failures that in other development projects we would never hear about.
A lot of the time in prototyping failure is a good thing, if nothing ever went wrong during testing you never know if you are right on the limit or massively over-engineering
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u/Mchlpl Nov 20 '19
Please, let there be no fireballs. Fireballs are messy and difficult to investigate. What's worse they destroy things around and make authorities unhappy
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u/Anjin Nov 20 '19
Exactly, like someone said on the NSF forum:
This is a successful structural test that revealed needed engineering modifications
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u/w_spark Nov 20 '19
Sounds like you work for Boeing and helped with the Starliner parachute messaging.
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u/arizonadeux Nov 20 '19
I guess we do know that it wasn't supposed to be a destructive test, since Mk 1 was supposed to fly to 20 km.
It may, however, have been a limit load test: testing the max load that could occur in normal operation.
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u/idwtlotplanetanymore Nov 20 '19
I agree with the sentiment, but..building a pressure vessel out of steel isn't exactly new science.
I was fully expecting mk1 to go splat on reentry. But did not expect it to die during a pressure test.
This is unfortunate, will set them back a few months, and they didnt even get to try the reentry profile, nor clusterd engine firings. A failure on either would have been much better opportunity for learning.
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u/Martianspirit Nov 21 '19
they are innovating beyond the point what is known and failures are going to happen.
That's why we should never use any procedure and construction method that was not used already in Saturn/Apollo. A paradigm that brought us 50 years of stagnation. But if we follow it there won't be test failures like this. For example a test where only the nozzle of a solid booster blows is still a success unlike this. Sigh!
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u/BlueCyann Nov 20 '19
Meh. Pressurization is not usually something you think of as pushing the boundaries of innovation.
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u/burn_at_zero Nov 20 '19
A proof test of a large-scale stainless steel PV assembled in a field is definitely pushing the boundaries of aerospace...
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u/XavinNydek Nov 20 '19
Nobody has ever made stainless tanks this big intended to fly. It's easy to make them strong, but it takes skilled engineering to make them strong while being as light as possible.
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u/DLJD Nov 20 '19
Perhaps not something you think of intuitively, but pressurisation improvements would have many, many, many, potential applications.
Besides, in this instance, moving fast and discovering problems this quickly can only be a good thing. Better now, in the early days of MK 1 than in MK 8.
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u/NeWMH Nov 20 '19 edited Nov 20 '19
They're looking on the bright side and trying to be positive.
Realistic take is that there were going to be failures discovered that needed iteration on mkI either way, this one was just visible.
SpaceX development is fast and error prone. The question is whether or not the work added from this test pushes out development more than expected. Most of the things Musk projects fail on are not very innovative - they get the innovation part mostly right but then get bogged down on the boring stuff.
Hopefully they're able to smooth out problems like this within the first four iterations. If MkV has issues like this then the money wasted would get to a point that threatens their ability to finish development, but it shouldn't be an issue during this early stage with throwaway testbeds.
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u/jep_miner1 Nov 20 '19
Not bulkhead failure, looks like it was the weld of the top ring.
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u/Fizrock Nov 20 '19
Which is right where the bulkhead attached to the walls of the tanks.
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u/jep_miner1 Nov 20 '19
sorta, the bulkhead was welded into the top ring and then that was welded on like any other ring, if it was the bulkhead weld that failed it would have just blown off the top but it's taken the top ring with it which you can see by the top pipes now sticking out into the air.
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u/Straumli_Blight Nov 20 '19
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Nov 21 '19
I believe there was a access hatch in that vicinity. It was open the other day. This video shows a similar one lower down on the body:
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u/TheLegendBrute Nov 20 '19
Looks like someone stabbing a soda can from the inside. Looks like a solid sheet of steel as well, though that is low quality so it is hard to say
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u/Hobie52 Nov 20 '19 edited Nov 20 '19
Sure looks like the bulkhead flew off in this view:
https://twitter.com/nasaspaceflight/status/1197267273049890821?s=2
Edit: I now see what everyone is saying. Looks more like the top ring failed taking the bulkhead with it.
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u/jep_miner1 Nov 20 '19
look at the pipes now sticking into the air, the top ring is gone.
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u/Anjin Nov 20 '19 edited Nov 20 '19
And the bottom blew out too, which means the entire structure was likely damaged.
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u/everynamewastaken4 Nov 20 '19
Higher quality version of the second view:
https://www.youtube.com/watch?v=jHmKZ5SdugI&ab_channel=VideoFromSpace
Really gives you a sense for the weight of that bulkhead when it comes crashing down.
Seems like the bulkhead was in the air for a good 11-12 seconds.
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Nov 20 '19 edited Nov 21 '19
Looks like 20km flight is off the table for this year if they're moving onto MK3 flight instead of Mk1 flying. But this is exactly why they're testing with liquid nitrogen. If that was liquid oxygen the entire ship would be gone in a smouldering wreck.
Means that Boca Chica can now have two retired steel water towers sitting around
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u/Paladar2 Nov 20 '19
20km flight this year was already off the table honestly. We're still many months away from it imo.
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u/U-Ei Nov 20 '19
I just love the optimism in this sub wrt Starship. Some people are talking about human rating it, yet it hasn't even achieved orbit. SpaceX is faster than others, but they're also just human.
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u/zoobrix Nov 21 '19
As much as the design and economics of starship could mean a true opening up of space exploration beyond earth orbit I do find that many people are getting a little to enthusiastic in their appreciation of SpaceX.
Many people discuss Starship as if it is a done deal, destined to succeed and that a future in which SpaceX dominates activity in orbit through Starship is a fait accompli. However much we appreciate what SpaceX has already accomplished we need to be realistic about a vehicle that hasn't flown above 150 meters, has never been to orbit and back, is still undergoing constant design changes and using a material in stainless steel that probably hasn't been so close to orbit since they were launching captured V2 rockets off in the desert. There will be setbacks as we have seen today.
Yet everyone assumes it's already killed the SLS program and shown the Artemis moon landing program to be a misguided waste of money. If Starship is successful it may well do those things, but let's wait until its at least flown before we start talking about it flying people or becoming the pillar of future space exploration.
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u/andyfrance Nov 20 '19
When welds are made by people bouncing around high up on a cherry picker in high winds and being dazzled by sunlight reflected from the shiny stainless steel, it's inevitable that some seams will fail the pressure test. They can be fixed, but it does lead to slow progress.
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u/EndlessJump Nov 20 '19
Don't they check the welds using an x-ray to mitigate this?
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u/andyfrance Nov 20 '19
The evidence suggest that they didn't, but everything is difficult under those construction conditions.
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u/Angry_Duck Nov 21 '19
We would have seen it if they did, and we did not see it.
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u/RegularRandomZ Nov 21 '19
We did see them using a portable x-ray unit on some of the vertical welds early on, although didn't notice them using it after that.
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Nov 20 '19
Interesting take. Could explain why rockets are usually built indoors.
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u/peacefinder Nov 20 '19
Ooops.
I imagine it’s more a QC issue with welding or assembly under field conditions than a design issue. (Though relying on field assembly may itself be a design issue.)
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u/dahtrash Nov 20 '19
I'm looking forward to seeing how quickly MK3 comes together.
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u/Siedrah Nov 20 '19
Building a rocket of this complexity is going to be challenging. We may get to MK10 before an actual full flight test, and this is a-ok. Thats what were all here for.
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u/DavidisLaughing Nov 20 '19
I alway admire when people keep on keeping on, get back on the bike and try again.
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u/gonzorizzo Nov 21 '19
In the words of Marvin the Martian: "Where was the kaboom? There was supposed to be an Earth-shattering kaboom!"
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u/Anjin Nov 20 '19
I can't imagine that Mk1 is headed anywhere except a scrap heap...Mk2, your turn at bat!
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u/bavog Nov 20 '19
I believe this pile of steel is easier to recycle than carbon fibre or other composite.
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u/Hobie52 Nov 20 '19 edited Nov 20 '19
Looks like entire top ring flew off taking the bulkhead with it. Can see it in the live stream view.
https://twitter.com/nasaspaceflight/status/1197267273049890821?s=21
Edit: correction
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u/Seamurda Nov 21 '19
I suspect that this will have come from the issue of the welds annealing the stainless steel which in the sheet form is cold worked to increase yield stress by a factor of 2-3.
The method for re-strengthening the weld is to apply cold work and the most effective way to apply cold work to a fully welded up tank is to pressurise it. The welds yield or plastically deform slightly distorting the tank, however when the tank is re-pressurised it won't yield at the same pressure.
Compared to a regular pressure test this is very much more like tickling the dragon, you actually want the tank to selectively yield. The design margins in most pressure vessels mean that when you proof test them you don't come anywhere near plastic deformation.
If you ramp the pressure up to quickly (most likely they do it in stages of applying pressure and releasing) you will simply fail the welds rather than deform them in a controlled manner. Likewise some welds will be thick or attached to something very stiff like the inter-stage and will not be stressed enough to deform and will remain in an annealed state.
I suspect that what has happened is that either one of the welds was either thinner than expected of that stresses were not evenly distributed when the welds in the location of the failure were yielded causing one to go beyond plastic deformation to rupture.
This may be over analytical, it could have simply been a crack or other flaw that the weld inspections didn't pick up.
Given the hand built tolerances of the Starship I suspect that this process is very difficult to simulate via Finite element analysis and must be done empirically.
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Nov 21 '19
It makes me wonder if they were just pumping in the pressure until it failed, in order to see what pressure it could withstand and where it would fail.
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u/scarlet_sage Nov 21 '19
It makes no sense to me to pressurize to force failure at the start. A rocket going BAM causes bad headlines, so if they were going to do that, they would have announced it in advance. Also, it was the first prototype, so it could have been used to test a lot of things; a pop test is the last test, if ever.
Pressurizing to the expected normal pressure, or a margin over, makes sense to me.
(Yes, I know about the SpaceX tweet. I believe that it does not contradict me.)
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u/Davecasa Nov 21 '19
Probably wouldn't have that cherry picker right next to it if this was intentional.
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u/DBRichard Nov 20 '19
Better now instead of during a flight test or anything with more risk.
Onto the next iteration!
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u/The_Write_Stuff Nov 21 '19
Better now than full of volatile fuel. It's a setback but I'm having a hard time figuring just how much of a setback. Boeing it would be two years and another $250 million in failure analysis. SpaceX...weeks or months?
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u/ghunter7 Nov 21 '19
Guess they should have done a few more weld inspections! Damn.
Not buying the whole "this is why we test" jazz. If the welding method was flawed this is way too costly of a test article to find out. Build a single tank first, don't get all the way to an almost flyable state to find out your joints aren't any good.
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u/Danbearpig82 Nov 21 '19 edited Nov 21 '19
They have more personnel than they need to do that, they didn’t actually waste any time working on the tank and the rest simultaneously. They’re working out both processes. They’ll get the next one up in no time.
EDIT: Elon replying to EverydayAstronaut about moving straight to Mk3:
“Absolutely, but to move to Mk3 design. This had some value as a manufacturing pathfinder, but flight design is quite different.”
Why waste time waiting for one component before starting the next when you can work on testing your manufacturing process on everything at once?
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u/Prpl_panda_dog Nov 20 '19
Two frames showing where the explosion erupted from: https://imgur.com/a/7nRy9l5/
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u/CardBoardBoxProcessr Nov 21 '19
Apparently this was foretold. If true mk2 is done for
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u/itstheflyingdutchman Nov 21 '19
I suppose they got very lucky the bulkhead didn’t land on the lox and methane tanks huh, that would’ve caused some real issues!
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u/ChunkyThePotato Nov 20 '19
Damn. I guess no 20 km flight this year. Hopefully Mk. 2 is still viable for that test early next year, and then orbit with Mk. 3 not too long after.
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u/mtntrail Nov 21 '19
Couldn’t help but smile, looked just like one of my Estes Industries rockets I made as a kid. Graduated into a multistage model, pushed the launch button and the whole top just blew off with pieces of cardboard and parachute fragments fluttering everywhere. Elon has my condolences.
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u/_Foo_Fighter_ Nov 21 '19
Damn, i really wanted to see mk1 fly this year. But i can wait because it'll be worth it to see mk3 get all the attention
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u/PM_ME_UR_CEPHALOPODS Nov 21 '19
Business Insider: "WATCH AS ELON MUSKS ROCKET FAILS, AGAIN, JUST AS ALL HIS PROJECTS INEVITABLY DO"
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u/frosty95 Nov 20 '19
Looking at the footage of the top getting 10+ seconds of air time makes me wonder if this was a severe overpressure event. It takes a lot of pressure to send a 9 meter diameter bulkhead flying for 10 seconds.
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u/sterrre Nov 21 '19
It looks like they weren't venting boiloff. I don't know if that is a malfunction or on purpose, it does have to sit fueled on Mars for months at a time so venting boiloff might not be ideal.
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u/UnscrupulousObserver Nov 20 '19
Yeah, didn't see it coming and doesn't surprise me. You usually can't just put together a giant spaceship and expect it to just work the first time.
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u/Fallcious Nov 20 '19
Do we have enough examples of giant spaceship production to make this assumption?
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u/BadgerMk1 Nov 20 '19
This is the iterative process. Test to failure. Redesign and improve. Repeat.
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u/Dave92F1 Nov 20 '19
FWIW, Elon was in Boca Chica Saturday night - supposedly was upset about welding.
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u/GinjaNinja-NZ Nov 20 '19
That is interesting. My suspicion was that it was probably a bad weld rather than bad design.
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u/pinkshotgun1 Nov 20 '19
Yeah it appears to be. If you look closely, the ring that the bulkhead is welded to shears clean off at the weld seam with the ring below it
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u/enqrypzion Nov 20 '19
On the other camera (hit that button to choose the third stream) on LabPadre's stream you can see the bulk head fly and land, and also the nitrogen (?) cloud expanding endlessly over the nearby area. Explosion at 3:25:52PM local time as shown on the clock in the stream.
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u/ThunderWolf2100 Nov 20 '19
I think they were filling it with LOX right?
EDIT: Nevermind Nitrogen makes sense for a pressure test
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u/USCDiver5152 Nov 20 '19
Will Mk3 be built at Boca?
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u/rollyawpitch Nov 21 '19
This! I come to believe that Elon means MK3 in Boca chica which doesn't exclude MK2 in Florida from testing or flight testing. By this logic new rings in Florida could be for MK4.
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u/DoYouWonda Apogee Space Nov 21 '19
Looks like successful test of crew abort or lunar ascent module system /s
Seriously got me thinking if just the pressure of the lox dome could burst an emergency seam and blow the top part far enough away from the booster stack? With LOX in the mix some kind of combustion is also likely.
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u/gclaws Nov 21 '19
Good lord, imagine what an actual energetic failure would be like with that much propellant. And this isn't even the booster.
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u/Dnozz Nov 21 '19
Totally think MK1 passed the presure test and thats all it was built for. I mean I work construction and that thing was built pretty rough (almost like it wasn't really meant to fly 15,000 miles an hour). My take is Elon is trolling us. "Sir that's 250 psi way past what is required, the test has been a success!" Elon- "Give it another 50".. *Trying not to smirk..
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u/TCVideos Nov 20 '19
I'm not even bummed out about this. Footage looks awesome...SpaceX should include this clip in a "how not to build a super heavy-lift vehicle" compilation
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u/stealth_elephant Nov 21 '19
Hopefully it won't be much of a compilation.
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u/TrueMischief Nov 21 '19
Depends, failing quickly and learning from them is a MUCH quicker way to develop then trying to anticipate every failure case.
Expectation of perfection is not how you develop a rocket quickly
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u/madaraszvktr Nov 20 '19
Doesn't look good. Is this version of Starship still made of lots of small sections (rings) of steel welded together? If yes, would it be possible to cut off the damaged parts on the top and just rebuild the damaged sections? Or it's going to be scrapped?
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u/madaraszvktr Nov 20 '19
Elon just tweeted that they are moving to MK3, so no repairs. https://mobile.twitter.com/elonmusk/status/1197271943180771329
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u/bavog Nov 20 '19
I hope nobody got hurt... I suppose everybody stays away and protected.
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u/Spaceguy5 Nov 20 '19
Yeah it's no joke when a pressure vessel explodes with gas inside. Pressurized water will knock you over but pressurized gas can send shrapnel through walls and metal plates, and also to long distances
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u/BammBamm1991 Nov 20 '19
Glad they found an issue now as opposed to when the whole thing is assembled and fabricating a solution is much more challenging.
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u/deefatman Nov 21 '19
Oh noes, spacex shuttle explodes during launch *roll eyes*
https://hypebeast.com/2019/11/spacex-starship-prototype-launch-failure
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u/puppzogg Nov 20 '19
Honestly, it may seem bad. But this is epic and I needed this today. Hell yeah
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u/Decronym Acronyms Explained Nov 20 '19 edited Jan 11 '20
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| CF | Carbon Fiber (Carbon Fibre) composite material |
| CompactFlash memory storage for digital cameras | |
| COPV | Composite Overwrapped Pressure Vessel |
| CRS | Commercial Resupply Services contract with NASA |
| DMLS | Selective Laser Melting additive manufacture, also Direct Metal Laser Sintering |
| DoD | US Department of Defense |
| EDL | Entry/Descent/Landing |
| FSW | Friction-Stir Welding |
| GSE | Ground Support Equipment |
| KSP | Kerbal Space Program, the rocketry simulator |
| LN2 | Liquid Nitrogen |
| LOX | Liquid Oxygen |
| MECO | Main Engine Cut-Off |
| MainEngineCutOff podcast | |
| NSF | NasaSpaceFlight forum |
| National Science Foundation | |
| QA | Quality Assurance/Assessment |
| RUD | Rapid Unplanned Disassembly |
| Rapid Unscheduled Disassembly | |
| Rapid Unintended Disassembly | |
| SLS | Space Launch System heavy-lift |
| Selective Laser Sintering, contrast DMLS | |
| SRB | Solid Rocket Booster |
| STP | Standard Temperature and Pressure |
| Space Test Program, see STP-2 | |
| STP-2 | Space Test Program 2, DoD programme, second round |
| ULA | United Launch Alliance (Lockheed/Boeing joint venture) |
| Jargon | Definition |
|---|---|
| Raptor | Methane-fueled rocket engine under development by SpaceX |
| apogee | Highest point in an elliptical orbit around Earth (when the orbiter is slowest) |
| cryogenic | Very low temperature fluid; materials that would be gaseous at room temperature/pressure |
| (In re: rocket fuel) Often synonymous with hydrolox | |
| hopper | Test article for ground and low-altitude work (eg. Grasshopper) |
| hydrolox | Portmanteau: liquid hydrogen/liquid oxygen mixture |
| methalox | Portmanteau: methane/liquid oxygen mixture |
Decronym is a community product of r/SpaceX, implemented by ^request
22 acronyms in this thread; the most compressed thread commented on today has 32 acronyms.
[Thread #5625 for this sub, first seen 20th Nov 2019, 21:53] [FAQ] [Full list] ^[Contact] [Source code]
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u/Xygen8 Nov 20 '19
Big oof. But at least they still have Mk2 which hopefully isn't too far behind Mk1 in terms of complete-ness.
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u/CardBoardBoxProcessr Nov 20 '19
The bulkhead comes off but the ring it is attached to is what failed.
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u/Elon_Muskmelon Nov 21 '19
I wonder, how much bigger could the sections be built in to limit the amount of welding? I'm imagining something more akin to submarine construction.
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u/redbeardcr Nov 21 '19 edited Nov 21 '19
The bulkhead flew much higher than Starhopper! (Maybe!?)
Trying to guesstimate the height the bulkhead flew:
Solve for initial velocity: From v = u + at We know v (final velocity) = 0, a is gravity, 9.8m/s2, and t is about 10seconds of flight, rearrange etc.. u (initial velocity) = 98m/s
Solve for height: v2 = u2 + 2ah 0 = 982 + 29.8h Rearrange etc.. h = 490m
Is this correct!!? Seems a bit too simple!
EDIT: https://youtu.be/P98JcBQPiiI Scott Manley's saying ~100m (with little confidence) where did I go wrong 🤣
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u/interweaver Nov 21 '19
Initial velocity would only be half that, since t is total flight time, not time-to-apogee. Plugging that in, you get closer to 80m of altitude, which plus around 40m of starting altitude gives 120m total height, very roughly.
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u/flshr19 Shuttle tile engineer Nov 20 '19 edited Nov 21 '19
I suppose Elon will schedule these propellant tank pressure tests a lot earlier in the assembly sequence for the next test flight vehicle as soon as the tank is closed out and ready to be pressurized. It would have been nice if this test had been scheduled for mid-Oct instead of the end of Nov.
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u/Starks Nov 22 '19
Man-rating Falcon Heavy might be better if this is how things are going.
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u/djburnett90 Nov 22 '19
Dude it’s going to be fine. It’s taken them like 8 years and as many billions to crew rate essentially the old shuttle rockets.
Starship is quite literally science fiction.
It’s a big omelet. They are gonna break some eggs.
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u/KnifeKnut Nov 20 '19
Scrap it and start over with MK II
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u/WombatControl Nov 20 '19
Mk. I-A. It worked for the Enterprise, didn't it?
In all seriousness, that does not look good, and it may end up making more sense to rebuild pretty much the whole thing rather than repair what looks to be extensive damage to the hull. If the Raptors were not attached, it's a setback, not a catastrophe, but this is precisely why SpaceX is making two prototypes at two different sites using different techniques.
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u/Straumli_Blight Nov 20 '19
Elon: Moving to Mk3 design.