SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

https://twitter.com/NASASpaceflight/status/1197265917589303296

by _Microft • 7 years ago

283 244 7 years ago

_Microft3• 7 years ago

It looks as if not only the bulkhead got separated but also the top-most ring where it was attached. I don't remember right now how that section looked, but maybe it was not the bulkhead at a fault but the seam between the first and second ring from the top.

SECProto• 7 years ago

I agree that's what it looks like. Interestingly, during fabrication, the bulkhead was attached to the ring, and then the whole ring was lifted up and welded on. Maybe there was interaction of the heat affected area from the two welds? The bulkhead was welded only ~100mm up from the bottom of the ring.

hsnewman2• 7 years ago

And that's why they are testing it.

mdorazio• 7 years ago

Yup, curious to see the analysis of this failure when/if it's available. Failures like this often provide a great view into the difficulties of aerospace manufacturing and testing along the entire supply chain.

cma2• 7 years ago

They are supposed to begin personal cross continental flights on this thing in just a few years for a bit more than the cost of an economy coach plane ticket.

A bit before that it is supposed to do a manned moon flyby in 2023.

cma2• 7 years ago

Sources:

New York to Shanghai slightly more than economy ticket by 4/2028:

https://www.vox.com/2018/4/11/17227036/flight-spacex-gwynne-...

Moon 2023:

https://www.scientificamerican.com/article/spacex-plans-to-f...

pardavis2• 7 years ago

This twitter reply sums it up well:

“SUCCESS! We now now max pressure the tank can hold and the damage a rupture might do.”

Baneofbatman• 7 years ago

Ah so this wasn't an accident? They needed to know the pressure limits so they purposely blew the bulkhead?

lmilcin2• 7 years ago

Well, we know max pressure THAT PARTICULAR TANK could hold.

Don't get too excited about the damage, in space it does not matter much, the crew is screwed anyway.

taneq5• 7 years ago

Good news, everyone!

lmilcin2• 7 years ago

Depends on what kind of test that was supposed to be.

If they pumped it until it explodes it would be a kind of test (also called experiment) where it makes sense.

If you design something with a margin of safety, then pump it to working pressure and it blows, then it means you made a mistake. If you made a mistake it shows you don't know what is necessary to design a rocket (yet).

Seriously, they don't build skyscrapers or bridges and leave for 5 days to see if they topple to prove the design was correct.

DennisP2• 7 years ago

I think SpaceX has proven they know how to design rockets. But they are newcomers to building rockets from welded steel.

Retric5• 7 years ago

Rockets are designed to have a vastly lower margin of safety. If they never fail in testing that’s a sign you’re over engineering it and sacrificing cargo capacity, which is a bad thing. That said, these failures should be uncommon.

outworlder2• 7 years ago

If you made a mistake it shows you don't know what is necessary to design a rocket (yet).

Yeah, sure SpaceX doesn't know what's necessary to design a rocket.

larnmar• 7 years ago

Seems like the difference between unit tests and integration tests.

AYBABTME• 7 years ago

Skyscrapers have been built again and again, and they have much different constraints. Starship Mk1 is the first of its kind.

playa1• 7 years ago

I expect this was more likely a manufacturing mistake. It was assembled night and day under a very tight deadline.

tus882• 7 years ago

Boeing intentionally snaps of the wings of prototype aircraft to find the breaking point/prove the margin of stress.

iamgopal• 7 years ago

At least the pump is working and generating pressure.

azernik2• 7 years ago

This and the Mk2 prototype in Florida are mostly experiments with manufacturing processes; I would not be surprised if there were a reliability problem with their methods that weakened the product.

elihu2• 7 years ago

Seriously, they don't build skyscrapers or bridges and leave for 5 days to see if they topple to prove the design was correct.

Perhaps a better analogy is carving a violin top. Skyscrapers and bridges can be overbuilt without destroying their utility, but a violin has to be as thin as possible without breaking if you want it to function well as a violin.

Davesjoshin• 7 years ago

Yea, there is something about all the attention on this thing that stresses me out. Its a prototype, right? There is going to be things that appear bad, but its really just a treasure chest of data.

mattrp2• 7 years ago

That’s one way to get the neighbors to move!

vkou2• 7 years ago

It depends on whether or not there was a reasonable expectation that the test was going to result in a failure.

Suppose you bought a used car, and the brakes failed before you could drive it off the dealer's lot. The dealer graciously fixes the problem, and points out the great news - that nothing catastrophic happened, and that the problem is now fixed!

You would, of course, start wondering - what other unexpected failures are going to take place, after you drive out of the dealership. Maybe nothing. Maybe something life-threatening.

If the failure was a surprise for everyone involved, I'd be worried - because other surprises might not get caught in testing. If it was a 'Well, we're not sure what would happen', I'd be less worried.

caconym_• 7 years ago

I mean, sure, but they certainly wanted to get more data out of it than they did. This is a setback.

cracker_jacks• 7 years ago

Is the Starship Mk1 more structurally sound than it looks? From a first glance and having no knowledge of its design, it looks like an empty soda can that would deform at the slightest disturbance. And the way it crumpled in the video doesn't seem far off from what I would expect.

MattRix• 7 years ago

Yes, your impressions are wrong.

JshWright10• 7 years ago

Not really... a soda can is a pretty good analogy, actually.

roywiggins• 7 years ago

Rockets are actually pretty easy to poke holes in. They're meant to keep stuff in, not out. A dropped torque wrench blew up a Titan.

https://en.m.wikipedia.org/wiki/1980_Damascus_Titan_missile_...

mlyle2• 7 years ago

An 8lb socket dropped 80 feet. That's going to put a heck of a dent in almost anything.

glup• 7 years ago

There's also a fantastic This American Life about the incident: https://www.thisamericanlife.org/634/human-error-in-volatile...

contravariant• 7 years ago

It's somewhat impressive that the actual nuclear warhead didn't so much as leak. Which is what's supposed to happen but still you don't usually design something to withstand a botched missile launch capable of 'catapulting' a 740 ton door.

LeoPanthera2• 7 years ago

Non-mobile URL:

https://en.wikipedia.org/wiki/1980_Damascus_Titan_missile_ex...

CydeWeys7• 7 years ago

Soda cans are actually incredibly strong for their weight.

db48x• 7 years ago

At least when filled and pressurized.

the8472• 7 years ago

You don't want your rocket to be heavier than necessary. They're usually dead weight once in orbit. So yes, they're a bit like a soda can. Just as strong as necessary.

JshWright10• 7 years ago

You're not wrong that Starship has very thin walls, but they're actually quite thick compared to some rockets. There are rockets in use today that have to be pressurized to avoid collapsing under their own weight.

cududa2• 7 years ago

Any lead on where I can read on starship technical docs? Things like wall width

manicdee• 7 years ago

Yes, rockets are basically soda cans full of propellant with rocket engines on the bottom and the payload usually on the top.

They are entirely constrained by thrust versus mass, so the designers make the structure as light/thin as possible while still being able to handle the acceleration forces when fuelled and pressurised.

If the weight of the rocket itself is too high it will not be able to lift any payload. If it is too light it falls apart in flight (or in one spectacular case, crumples in on itself when pressurisation fails).

fsagx• 7 years ago

Atlas booster:

https://www.youtube.com/watch?v=imkdz63agHY

errantspark2• 7 years ago

You're actually spot on. For example the Space Shuttle main tank had a 96:4 contents:structure ratio[0]. A soda can is 94:6.

[0] https://www.nasa.gov/mission_pages/station/expeditions/exped...

dehrmann3• 7 years ago

How does that compare to commercial airplanes?

andrewflnr• 7 years ago

If you go back a couple hours in the linked live feed you can find the event pretty easily. Look for the big plume in the preview when you hover over the progress bar. About 1:50 ago at this working writing. I guess it would have been around 1540 EST.

zionic• 7 years ago

Looks like the welds holding the bulkhead on failed.

For those who aren't keeping up with this the failure was on the Mk1 prototype. Mk2 has been build nearly in parallel with Mk1 and will take over early flight testing (20km hop). Elon has tweeted that this team will jump to Mk3 instead of trying to repair Mk1.

WalterBright• 7 years ago

Airliners rarely use welds because they're very hard to make with consistent high quality and are also very hard to inspect. Instead, they're riveted together.

kristianp• 7 years ago

Is the mk2 in the parallel location?

TheSpiceIsLife• 7 years ago

I don’t know the specifics of this particular setup, but aren’t pressure vessels usually tested hydrostatically.

Water, for example, can be pressurised without actually compressing, and therefore doesn’t undergo rapid expansion when a failure occurs.

There may be reason that precluded pressure testing with a fluid tough.

AWildC182• 7 years ago

Compared to the fuels that the vessel is designed to carry, water might as well be liquid lead. It would easily crush the structure before you got enough in there to do hydro testing.

Edit: correction, looks like they're using methane/LOX. Methane is 422g/L and LOX is 1141g/L (compared to water at 1000g/L). If it was the LOX tank then they could have probably hydro tested it. Not so much with the CH4 which is probably the upper tank? It also bears mentioning that they would want to test at the appropriate temperatures. Water isn't great for hydro testing at LOX/liquid CH4 temps.

m0zg• 7 years ago

How do you "hydro" test it at cryogenic temperatures, where physical properties of the vessel material are markedly different?

elihu2• 7 years ago

Maybe weight? Filling something that big with water would be very heavy; maybe it's not strong enough in all the right places to support that much mass.

JshWright10• 7 years ago

Water is lighter than liquid oxygen (which is what this tank would be holding in "production"). For the purposes of this test, they were likely using liquid nitrogen, which has ~80% the mass of water.

kev0096• 7 years ago

I had an unpopular opinion amongst friends that this thing looked like a total piece of shit, like a movie prop. They were using rented lifts and cranes to assemble it in the field. Clock right twice a day or maybe there's a reason everything about Apollo spacecraft was meticulously assembled.

cyrux004• 7 years ago

I wish more smart people like you worked there.

irrational• 7 years ago

Well, it's not like this is rocket science. Oh, wait...

cududa2• 7 years ago

Yes because without this dude they would’ve never invented self landing reusable rockets

bborud• 7 years ago

Depends on what they're testing.

Every single one of my electronics prototypes look like shit. About one five of them produce smoke and burn marks. Every twentieth does something dramatically unexpected (usually entertaining).

JshWright10• 7 years ago

Starhopper looked just as "rough and ready" but completed a successful test flight a few months back.

Klathmon3• 7 years ago

I have a feeling that they could blow up another dozen of these and still be spending less than doing it the "traditional" way of in cleanrooms and the VFAB building.

This was a prototype that they've publicly said was most likely never to reach orbit, they are building this stuff right now to learn, test, and prove that their design works and find improvements that can be made.

kev0096• 7 years ago

Any elementary student of history can tell you how bad an idea this is. Apollo 1 almost ended the program. A backlash in public opinion will crater SpaceX in the market and legislature.

There is no space mission in the near decades worth the loss of human life. Economy in terms of money is no priority if you are to undertake human space flight. Move fast and break things is cute for a global search index or regressing public discourse and attention span; it's astronomically stupid and not acceptable for safety of human life.

If this were a billionaire playboy stroking his ego and putting his own money and life on the line who cares. It's not, he's using my tax dollars and is going to hurt others for negligible gain.

newnewpdro• 7 years ago

It looking like a piece of shit is an unpopular opinion?

I assumed that was a consensus. The thing isn't trying to win any beauty contests, it's covered in ugly seam welds.

And none of that matters, not one bit.

kev0096• 7 years ago

It's not cosmetics. What kind of tolerances can you get dangling a massive assembly from a crane in the wind? How many people are cross checking the work? What kind of instrumentation are you using to check joint quality and integrity at these heights from a genie lift? It’s hard to shoot a stucco roof from a genie lift, I can’t help but laugh out loud at the assertion this is sane. Astronomically stupid.

perspective12• 7 years ago

During prototype tests you don't have to target 6-sigma, obviously, but I hope we get a post-mortem without spin.

vkou2• 7 years ago

When their entire business depends on very carefully managing their PR, you're not going to get a public post-mortem without spin.

If a government regulator runs the investigation, you might. I don't know if a regulator's going to get involved in this, though.

senectus1• 7 years ago

When their entire business depends on very carefully managing their PR

You really think this? My perception is that their PR is fairly blunt and upfront. while they may not tell you everything they dont seem to be trying to "spin" anything

adventured• 7 years ago

These are the guys that give us amusing compilations of some of their more explosive mistakes:

https://www.youtube.com/watch?v=bvim4rsNHkQ

So much for very carefully managing PR.

nickik• 7 years ago

When their entire business depends on very carefully managing their PR

That is simply wrong. Their business depends on reliably launching rockets and delivering payloads to station. And that is what they have done.

If a government regulator runs the investigation, you might. I don't know if a regulator's going to get involved in this, though.

They are not going to. Starship is a SpaceX project that is not financed by NASA or the DoD.

NamTaf3• 7 years ago

Oh dear! It looks like someone accidentally divided by 2 for the cylindrical hoop stresses, forgetting that they're not the same equation as for spherical stresses. :)

Less facetiously, a thin-walled cylinder's stress is a function of pressure, radius and thickness with the equation:

sigma = P*r/t

whereas for a sphere (including the spherical end caps on a cylindrical pressure vessel), it follows the equation:

sigma = Pr/(2t)

To me, it looked like it failed around the join between the spherical end cap and the cylindrical body, where this transition between stress regimes occurs, which is a common weak spot in the above analysis. This is a canonical early engineering statics problem.

It's worth noting, though, that all of the above is almost certainly a gross simplification and likely has very little bearing on the actual problem. It's fun to simplify and hypothesise, though! Also, unplanned failures make for great viewing :)

taneq5• 7 years ago

That's why you take your maximum design stress and double it, right? /s

namirez• 7 years ago

I don't know what happened here, but if I remember correctly, in rockets, safety factor is typically smaller than 2 or the design would be too heavy. But I guess the safety factor for pressure testing is 4.

Source: article 6.8.2.2 of this document; https://www.faa.gov/about/office_org/headquarters_offices/as...

Edit: I didn't see the "/s" before writing this comment.

d-sc• 7 years ago

Typically the factor of safety is not that high in the aerospace industry.

cdumler• 7 years ago

How else do you think I keep my reputation as a miracle worker? -- Scotty

soapboxrocket• 7 years ago

It's been a while since I did pressure vessels but it's usually 2.5 times for proof and 3.5 for burst. Then with added safety you usually need about 4x to actually see a "planned" failure. This is most likely a construction fault.

ew60823• 7 years ago

They left the nose cone off to save money. I wonder if the designer counted on some portion of the cone weight to support the cylinder head in their design?

davedx• 7 years ago

I don't think you can really count in weight on an object capable of flying into orbit or interplanetary space...

dsfyu404ed• 7 years ago

I know that SpaceX is trying to make space flight cheap so they have to figure out how to do things like use cheap pressure vessels but this mode of failure is exactly why aerospace pressure vessels have long been made from a hot rolled body (as opposed to cold worked and welded).

https://www.youtube.com/watch?v=MvADC43EHmE

IshKebab• 7 years ago

I'm fairly sure SpaceX's engineers know 1st year mechanics.

londons_explore• 7 years ago

Aren't pressure tests done with water?

That way, since water is non-compressible, if it fails, you just get a small hole or buldge somewhere rather than the catastrophic damage seen here.

Perhaps they already tested with water and now needed to test with the real fuel/oxygen to get the temperature correct?

taneq5• 7 years ago

Is it strong enough to take a full tank of water? Liquid methane weighs less than half what water weighs.

JshWright10• 7 years ago

Liquid oxygen weighs more than water though...

dzhiurgis2• 7 years ago

Maybe they can use liquid nitrogen?

sfblah• 7 years ago

Whoever gets in that thing is spam in a can /s (quote from the right stuff)

torgian• 7 years ago

I think it’s good. Better to find the flaws now and do a resdesign, instead of having astronaughts being blown out into space ;)

djohnston• 7 years ago

for some reason i feel like im watching a 2nd grader's baking soda volcano project. i guess it's the perspective of the camera, or im not accustomed to the looks of prototype rockets, but to me it looks like a paper mache diorama

ohazi• 7 years ago

Starship looks particularly shoddy because it's made from relatively small steel plates welded together. The welding process causes each plate to warp slightly, so the end result looks like a quilt rather than a nice uniformly smooth cylinder. Most rockets don't look like this. Most prototype rockets don't look like this either.

The argument has been that this is good enough to start testing structural features, and probably also good enough to do a little bit of low-stress flying as well. The first argument seems sound. I'm not so sure about the second... there are a lot of welds. At least a few of them are likely to be structurally unsound, and assessing weld quality is difficult.

In any case, for the "real" Starship, they plan to use a technique similar to the one they use on Falcon, where they roll a huge metal plate and then stir-friction weld along the seam. This kind of tooling is difficult and expensive to set up, and the configuration of the machinery and the material depends a lot on the actual design, which hasn't been finalized yet.

Apparently they're using thicker steel then they plan to use on the monolithically constructed version to compensate for weld quality, but I don't know... weld seams are great stress concentrators, and stress concentrations are where fractures are likely to form, and fractures on the skin of a rocket are usually catastrophic failures. All it takes is one defect.

_Microft3• 7 years ago

The Starships shininess makes it look even more wrinkly. If it wasn't reflecting its surroundings so well, you would not be able to see that it's not perfectly smooth.

Here's a similar effect on windows:

https://c8.alamy.com/comp/D60B28/distorted-reflections-in-a-...

That's why Starship can look a lot better when photographed from nearby - the view is tilted more upwards and the sky is reflecting in it which does not have enough details to let one see these wrinkles.

tus882• 7 years ago

Does fail early apply to Space tech development?

JshWright10• 7 years ago

It's worked fairly well for SpaceX so far...

boznz• 7 years ago

"You will learn more from your failures than your successes - so embrace those mistakes, as difficult as that sounds, and grow from them. When a project is successful, you're never really sure why, because so many elements come into play. However, when you fail, you always know why. That is how you learn and grow."

Lynda Resnick

killion• 7 years ago

I haven’t seen an mention if anyone was injured. Was there someone on the cherry picker?

elteto• 7 years ago

You would never have people around when doing high pressure ops. This might even have been a proof test, where the tank is pressurized to test for leaks so something like this failure is a plausible scenario.

double0jimb03• 7 years ago

I read this was a manufacturing pathfinder.

Manufacturing and assembly of high strength hardened steel is near black art.

Pathfinders do exactly what they say, they lead you through unknown territory to the outcome of the manufacturing journey you embarked on. Often things go boom, you find out why, add it to your corpus of black art knowledge, and keep pathfinding until you run out of budget / succeed / change mission.

So as manufacturing pathfinder, this is what success often looks like.

Roark662• 7 years ago

Why would they be using hardened steel for a pressure vessel that has to deal with vibrations?

Also, someone on twitter said a horizontal weld failed. If this is true I'm surprised they didn't do two things: - tune their welding procedure by destructive testing with the same type of steel - and X-ray (or use another non-destructive method) the welds after assembly.

Welding (including more interesting metals) is my hobby so I had an opportunity to see that there a huge amount of knowledge in the field. There are routine testing procedures that ensure situations like this one don't happen.

19870213• 7 years ago

As far as I know the type of steel they are using increases in strength as it gets colder, so that should be ideal for the LOX.

tinco• 7 years ago

Maybe they did both things, and the weld still failed. The rocket's being engineered, which means they make it as weak as possible without it blowing up. Those welds might be perfect in the x-rays, they might've done all sorts of destructive analysis, and still the thing might fail in staging.

Of course, they might also be on a deadline, and just went ahead and built it to spec and test it. But I don't think you can just say there's routine testing procedures that ensure rockets never blow up. If that were the case we wouldn't have needed SpaceX to reinvigorate the space industry.

lutorm• 7 years ago

They are using 301 stainless which, as far as I know, cannot be hardened.

combnoinipo• 7 years ago

What does pathfinder mean in the context of manufacturing?

celticninja2• 7 years ago

Essentially doing something for the first time, no one has built a steel structure of this size before, that will have to withstand the forces that this will be out through in normal operation.

madaxe_again2• 7 years ago

A fuzzball of patches and “good ideas at the time”. It’s like the first iteration of an app that never sees the light of day, as you finish, sit back, go “ah, an abomination”, and rewrite the thing properly with what you learned from the prototype.

I do this pretty much any time I’m doing something new - I have three revisions of a solar panel stand sat out on the lawn right now, each better than the last, as I needed to build the thing to see how it actually held up to forces as it’s easier and more accurate (ah, how do I fit a screwdriver in this gap to fasten this?) than doing an engineering simulation.

specialist• 7 years ago

Tabu search thru a semi-dynamic design space.

https://en.wikipedia.org/wiki/Tabu_search

double0jimb03• 7 years ago

At the highest level, the conversation looks like:

The design engineer: "We know on paper how the product needs to function in terms of strength, weight, durability, etc"

The manufacturing engineer: "We've never made something like this before. I've got a couple ideas how we can bend/shape/form/machine/weld these materials into the shape, but I don't know how those bend/shape/form/machine/welding operations are going to affect the underlying physical properties of the material. I know on paper these operations should be OK, and we can inspect them as we go, but again we've never done them before, we most likely will overlook something or discovery something new, so let's try one of them and break it early before we get too far down a potentially bad path."

The test engineer: "Well it worked up until X point then failed, here's the data for you design engineer and you manufacturing engineer, better try something else".

Design engineer: "Shoot, what we thought we were manufacturing isn't actually what got manufactured. Hmmm, is it even possible to make the part we need? Or do we now need to redesign the part because it can't actually be made. Let's try another approach. And maybe it's smart to pursue a few of these in parallel to increase our overall chance of success"

Those 3 roles can be the same person or separate organizations of hundreds/thousands of people. Requirements documents, manufacturing/quality reports, test reports, inspection reports are the language of this technical interchange.

CPLX• 7 years ago

I must admit that Elon has done some fairly impressive things, and I respect his hustle and innovation.

With that said, the cult that surrounds his projects where people say things like "this is what success looks like" when a big metal thing blows up unexpectedly or robot car goes flying off an exit ramp is a never ending source of amusement.

danielbln• 7 years ago

The cult is funny indeed, but do mind that the giant SpaceX booster rockets exploded in giant balls of fire a LOT before they eventually (and reliably) landed like in a sci-fi movie, on land and on a moving boat. SpaceX has earned some benefit of the doubt.

SmellyGeekBoy• 7 years ago

Way to misquote GP to confirm your preexisting bias. I think the quote you're looking for is:

"So as manufacturing pathfinder, this is what success often looks like. "

If blowing up a prototype enables changes to the manufacturing process that prevent the same thing happening later with a live crew on board, then it's considered a success. It doesn't matter who the CEO of the company happens to be.

taneq5• 7 years ago

You're saying this to a community with the mantra, "move fast and break things."

ehnto• 7 years ago

I guess the parent comment was pointing out that this actually wasn't unexpected, it was one of the expected failure modes for the test and it happened.

I don't see any constructive reason to look at it negatively, failure is part of testing. We don't test to find success, we test to find failures so that we can get them out of our systems.

ryanmercer• 7 years ago

With that said, the cult that surrounds his projects where people say things like "this is what success looks like"

Experimental rocket/spacecraft (that's a fairly rapid prototype as far as rockets are concerned), made out of non-traditional material for rockets, fails one way yielding tons of data to do it better on the next version.

That's some modicum of success no matter how you slice it. Go plug 'rocket launch fail' or 'rocket explosion' or some such into YouTube and watch various rockets failing spectacularly on the launchpad both during development and carrying actual payloads and compare it to this failure at this stage of development.

I mean, look at stuff like Apollo 1. An electrical fire killed all of the crew during a test less roughly a month before launch. Starship is a very early prototype that probably yielded more actionable data than the Apollo 1 accident did.

marktangotango• 7 years ago

Cult not withstanding, Elon has expressed on a few occasions how he's expected some rockets to blow up, and a few have. I've had the idea the past few years that he's felt he hasn't been pushing the envelope hard enough. Progress on Starship has been at an astonishing rate by anyone's measure.

I find it fascinating that we get to observe this all playing out in real time. You might agree.

double0jimb03• 7 years ago

Or that Elon Musk and SpaceX are doing real engineering work and other engineers recognize it and try to explain it to those who don't recognize engineering methods and processes?

hyperpallium• 7 years ago

Soumds similar to tracer bullet development.

dehrmann3• 7 years ago

There was a post on HN a few days ago about how SpaceX got a full examination, while Boeing more or less got a pass from Nasa. This is a different vehicle, but it gives an idea of the maturity of SpaceX. And yes, the earlier story was really more about trying to establish a pattern around the 737 Max failure, but that issue was at least complicated. This is just sloppy.

[1] https://news.ycombinator.com/item?id=21574080

paraiuspau• 7 years ago

"Was that the primary buffer panel?"

SergeAx• 7 years ago

Nothing blows up means you aren't innovative enough.

jjuliano• 7 years ago

They should opt for a single block of stainless steel carved into a rocket as a unibody design for added strength.

weinzierl• 7 years ago

Not the whole rocket obviously but milling the tank from a whole block has been done.

LandR• 7 years ago

The front fell off!

Ajedi32• 7 years ago

Comment from Elon Musk: https://twitter.com/elonmusk/status/1197271943180771329

Official SpaceX statement: https://twitter.com/thesheetztweetz/status/11973066177605591...

new_realist• 7 years ago

This integration test is way too late to be finding faults like these. This is top down design, which is expensive an error prone. The ship should be designed and tested in a bottom up fashion, such that the failure modes of every individual component is already known, as per Feynman. SpaceX is repeating the mistakes of the Space Shuttle program.

MR4D• 7 years ago

Just another test.

However...

To me there is an issue with large diameter pressured tubes - the point where the tube connects to the top is affected by the surface area divided by the diameter. Obviously one of those scales linearly, and the other squared.

That suggests to me (I'm definitely not a rocket scientist!) that the upper bound might be smaller than this diameter, or the weight will have to increase in order to beef up the strength of this point.

Pretty interesting problem to deal with now that they are this far into the design. I'm sure there are many possible solutions, and it will be fun to see what they come up with.

SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

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