SpaceX Starship SN4 launch vehicle prototype explodes after static engine test

https://techcrunch.com/2020/05/29/spacexs-starship-sn4-launch-vehicle-prototype-explodes-after-static-engine-fire-test/

by edward • 6 years ago

176 124 6 years ago

techcrunch.com

1014042• 6 years ago

Too bad, especially because only yesterday they put a weight simulator onto it. So it looked like it was going to fly.

Well, it did fly, just not in one piece.

defterGoose• 6 years ago

"Fly apart"

justaguy88• 6 years ago

rapid unscheduled hop

1014042• 6 years ago

... multi-directional hop

dreamcompiler2• 6 years ago

https://space.stackexchange.com/questions/10022/who-coined-t...

unstatusthequo• 6 years ago

Yeah given the delayed and soon upcoming actual human scheduled flight, this would have been maybe nicer to put off a couple days... just optics but still...

darkteflon• 6 years ago

Agreed - my first thought too.

whatshisface• 6 years ago

Watch this:

"It's actually good optics that it exploded, because it shows they aren't changing their schedules for the sake of optics. Political pressure to make the schedule fit the public's feelings was a major contributor to the Challenger disaster. So, having a tank blow up the day before a manned launch shows that SpaceX has overcome the challenges of the past."

(See? That spin makes the turbopump look like a stator. If I have a point it's that talking about optics is pointless, because you can make the optics anything you want by casting the right light.)

ncmncm• 6 years ago

Skip to "1:48 CT".

Diederich• 6 years ago

Disappointing to be sure, but it's why they already have SN5 (nearly?) complete and SN6 is well on its way.

I like how Elon Musk contrasted past and currently planned human space activity as 'Apollo' and the potential future as 'D-Day'.

The goal is to cheaply and quickly mass manufacture interplanetary space craft. I think that imploding/exploding early serial numbers are an expected early part of that path.

moneytide1• 6 years ago

Not disappointing - the more things that go wrong during the extensive series of tests developed and cataloged over the past several decades, the more we can correct and cement into permanence.

I'm looking forward to SN747 (the number corresponds with one of Boeing's standardized atmospheric flight models) sometime in 2024. I'm probably not thinking big enough though.

lutorm• 6 years ago

Believe me, it's absolutely disappointing. Not unexpected, mind you, but people would definitely prefer to not have things blow up.

Aeolun• 6 years ago

Not disappointing - the more things that go wrong during the extensive series of tests developed and cataloged over the past several decades, the more we can correct and cement into permanence.

To some extend, but just as with software, I’m super happy if my program just has zero bugs after all the testing is done.

This has never happened, but it’s nonetheless something to strive for.

watersb• 6 years ago

Rocketry is unforgiving. That's why they test.

trca• 6 years ago

Best way to figure out how complex things fail is to keep pushing them to their limit and observe

phkahler• 6 years ago

This on definitely started at the bottom. It almost looks like a leak created a FAE (fuel air explosive) mixture around it.

It also blew out the methane flare on the right.

dreamcompiler2• 6 years ago

Looks like the methane flare is what lit it, although it's difficult to judge distance in the video.

davidmurdoch• 6 years ago

It didn't. You can play it back frame by frame and see that it started beneath SN4.

Nerada• 6 years ago

For some reason this link re-routes me to "advertising.com".

pmontra• 6 years ago

All links to Techcrunch go to https://guce.advertising.com/collectIdentifiers?sessionId=1_... uuid> and Blockada [1] blocks them on my Android devices. I stopped visiting Techcrunch since they started to do that. I can always google the same news on a different site.

[1] https://blokada.org/

rrmm5• 6 years ago

If you catch the audio on this from the nasa space flight forum (I think?), it was pretty funny. They were speculating if it was a lox purge (vs a methane purge). They assumed lox, since if it were methane, the flare would..... BOOOM.

The timing was very perfect.

EDIT: https://twitter.com/NASASpaceflight/status/12664420878489600... has the audio with it.

Pfhreak• 6 years ago

A bit later they run the tape back frame by frame and determined the fire definitely didn't come from the flare stack. (Though in realtime it happens so fast they weren't sure.)

rrmm5• 6 years ago

Yup. but the timing was just too good. It was like the methane wanted to have a say in the conversation: "Acccctuaally,....BOOM"

ashtonkem3• 6 years ago

That video was almost certainly taken with a telephoto lens a long distance away, and telephoto lenses tend to compress distance. The flare could’ve been a long way away from the rocket, and a telephoto lens would make them look much much closer.

dmlittle• 6 years ago

What's the purpose of the methane purge?

baking4• 6 years ago

It was not intentional. There must be some mechanism to disconnect the external propellant lines before lift-off and they obviously disconnected unintentionally after the static fire. The best guess based on the way the flame spread was that both lines disconnected and there was a mixture of methane and oxygen just waiting for the right fuel-oxygen ratio before it was ignited on any number of post-burn hot spots. (I haven't seen any new info recently so this explanation may have been already superseded by more recent analysis.)

viraptor• 6 years ago

"More data is more better" (beginning of the video) is my favourite new engineering meme.

jokoon2• 6 years ago

"I don't know how nominal that is"

grishka• 6 years ago

"That was not nominal"

rrmm5• 6 years ago

I thnk they slipped a 'norminal' in on us. (A John-Insprucker-ism).

visviva2• 6 years ago

Would it have really killed their schedule so much to push this until after tomorrow's crewed flight? They're obviously unrelated, but it sucks to have this is the headlines the day before they launch astronauts.

ghostpepper3• 6 years ago

The astronauts are both veterans and one would assume they understand that this was not only a prototype ship but a prototype engine. Falcon has 50+ successful flights over four years since its most recent failure.

Hopefully they're not phased by this.

visviva2• 6 years ago

Hopefully they're not phased by this.

I doubt they are - my comment is about the PR impact.

carapace• 6 years ago

s/phased/fazed/

sneak3• 6 years ago

I thought the same thing at first, but I doubt very much this will be reported very widely. Despite it being huge in our circles, most people don’t follow this stuff very closely. Unless both SpaceX and NASA are pushing out stories at max volume with included press kits, anything they do will be basically niche at best.

Recall on the FH test flight how the loss of the center core was not announced immediately, and as a result of SpaceX delaying the announcement of the loss by an hour or three, very nearly 100% of the reporting on the topic was about their successful launch and landing of the two (heh) boosters, with no mention whatsoever of the fact that the launch also contained a failure.

An absolutely masterful PR decision, and one I learned a lot from, but also evidence of how fickle, inaccurate/incomplete, and flighty/shallow media attention is. For the vast majority of people and media outlets: nobody really pays attention to rockets in general, especially while the nation is burning/dying/being impoverished. You have to be insanely loud to penetrate that fog.

This isn’t headline news.

ghostpepper3• 6 years ago

When you put it that way, that masterful PR decision stands in stark contrast to this one. Any outlet that was planning to cover the launch on Wednesday and would never have covered SN4, but now plans to cover the Demo2 launch again today might be more likely to cover the SN4 failure.

baking4• 6 years ago

This was the fifth static fire of the same rocket and frankly it wasn't seen as high risk at the time. If it was, I am sure they would have postponed it, as they did for the planned short-hop.

Of course "high-risk" is a relative term. They had a 1.5 mile exclusion zone for the test and the handful of village residents a few miles away were warned to leave their houses to prevent injuries from broken glass, so there was obviously some risk.

This was really a just a potential PR problem for click-baity new organizations and casual observers not aware of all the different projects SpaceX is working on. No one from NASA going to say maybe we should scrub Saturday's launch because they know the two not related in any way.

Also, there are many Elon haters are out there. I had a few try to blame Wednesday's scrub on Musk or try to imply that it was a failure. (Of course the fan boys can be just as annoying.)

bryanlarsen• 6 years ago

This is the 4th Starship that has imploded or exploded. They only lost 3 Falcon 1's before their first successful flight, and Elon has publicly stated that a 4th failure would have bankrupted the company.

Those three Falcon flights were attempts to reach orbit with rockets that weren't prototypes so the failures were more significant, and they probably blew up a bunch of Falcon prototypes behind closed doors prior to the launch attempts, but it's interesting how three failures on Falcon was a big deal but four failures on Starship isn't. SpaceX is certainly in a different and much less precarious position now than it was in 2006-2008.

sneak3• 6 years ago

That’s how it goes with building something properly large, isn’t it? The speed range on first gear is more narrow than second, and third, and so forth.

I’m just glad SpaceX has the cash flow and team to be able to pursue something as ambitious as BFR. Humans are going to need many thousands of rockets like that one if we are to survive.

tsimionescu• 6 years ago

Humans are going to need many thousands of rockets like that one if we are to survive.

There is no chance in the next hundred years (I would bet more like 200-500) of a self-sufficient colony anywhere away from the earth. If humanity can't survive without rockets, it can't survive at all.

Not to mention that it is basically impossible to imagine that any technology that could allow a self-sufficient colony on another planet couldn't much more easily allow humans to live on earth after any catastrophe you could imagine short of cosmic ray events. It's much, much harder to live on Mars than on a post-apocalyptic earth, regardless of which apocalypse you care to choose (nuclear war, nuclear meltdowns in all nuclear power plants, catastrophic global warming, super volcanoes, meteor impact the size of the Cambrian event, you name it).

Sure, in the enormously long term there may be a need to leave the earth before the sun ages too much, or to try to have a chance against planetary collisions or gamma ray bursts.

dnautics• 6 years ago

It's interesting that a company with a revenue stream can tolerate more failure of declared prototypes more than one without can tolerate operational (if early stage) deployments?

HPsquared• 6 years ago

Morale, track record and investor relations are the difference.

Dylan168072• 6 years ago

The difference between some test parts on a stick vs. a full rocket is so vast that I don't think you can make any coherent/interesting comparison of the numbers.

It's like comparing 4 millimeters to 3 inches. It doesn't matter at all that 4 > 3.

beambot2• 6 years ago

Wat? It's totally meaningful to compare two length measurements, Even if expressed in different units.

I get what you're trying to say (and you are right!), but that's a bad analogy.

gpm2• 6 years ago

This isn't correct.

They lost many more than 3 Falcon 1 tanks during development. They only lost 3 Falcon 1 launches to orbit. There have been 0 starship launches to orbit - they haven't even built a first stage prototype yet.

hanniabu• 6 years ago

If I remember correctly, Elon said they expect ~20 failed tests throughout development as they test various designs and assembly techniques.

ashtonkem3• 6 years ago

And immediately after the 4th one flew, someone (NASA?) handed them a contract, which is kinda nuts.

agildehaus• 6 years ago

Falcon 1, flight 4 was the first privately-developed liquid-fueled rocket to achieve orbit. Not so surprising.

lmm• 6 years ago

I mean yeah, it's a viable business now. In 2008 they had no successful launches, no revenue stream, and had almost exhausted their seed funds. That's pretty normal.

unnouinceput• 6 years ago

Funny article, it stressed at least 4 times this is different from the normal flights ones they do regularly, otherwise covidiots/flat-earthears/conspiracists will fill forums with their cries. And I'm not sure they wont anyway.

danso• 6 years ago

I know these kinds of explosions aren't disasters per se, but at what point in development do these kind of destructive results become very unwanted? Or was that classic Calvin and Hobbes comic about bridge testing less of a joke than I had though?

https://www.gocomics.com/calvinandhobbes/1986/11/26

sacred_numbers• 6 years ago

When you start making the same mistakes over and over. As long as they learn new things with each iteration it doesn't matter if they blow up 5 or 50 ships. The actual material cost of these prototypes is probably in the low 6 figures. The biggest cost is the labor, but by iterating rapidly they are learning new manufacturing techniques, so if they weren't blowing up these prototypes they would be stacking them in a field or tearing them down anyways, since the value is in the process, not the final product, at this point.

Also, there are only an estimated 300 employees building Starships (although there are probably more working on engineering), so on-site labor costs are probably about a million a week. Since they can pop out a new iteration every few weeks they cost is probably only about a few million per ship. That's a lot of money in some industries, but it's a rounding error in rocketry. They could build dozens or even hundreds of prototypes for less than the cost of a conventional disposable rocket, like SLS.

The idea that the cheapest way to build a rocket is to blow up dozens of prototypes is a bit counterintuitive, but I believe it's the future. Organizations that move more slowly to avoid failures will fall further and further behind, since the tortoise only wins if the hare falls asleep, which SpaceX shows no signs of doing.

Civil engineers are able to use mathematical models to develop bridges because we've been building bridges for thousands of years, and they can build in huge safety factors. Fully reusable rockets have never been built before and can't afford the luxury of large safety factors due to the Rocket Equation, so testing to failure is the fastest way to learn, and when almost all of the cost is labor, fastest = cheapest.

baking4• 6 years ago

The latest from the President and COO of SpaceX is that there are 900 employees working at Boca Chica alone.

SergeAx• 6 years ago

Now, that's what I'm calling "move fast and break things"!

unixhero• 6 years ago

That's what tests are for.

kilroy123• 6 years ago

All this time, I haven't been convinced that this steel approach is better in the long-run than going the advanced composite route.

blackrock• 6 years ago

At some point during Research and Development, shouldn’t you figure out the math first?

jokoon2• 6 years ago

I wonder how many unfilmed explosions NASA had during the space exploration period.

vntok• 6 years ago

I'd wager probably none or a handfew at most. Frame-by-frame video was and still is important to incident analysis.

raverbashing• 6 years ago

I think NASA not so many, but space exploration started pre-NASA.

JPL predates NASA https://www.youtube.com/watch?v=jlNz634TjN0

swarnie_• 6 years ago

"That was not nominal"

Bloody brilliant. Hopefully they got some good data from that test

londons_explore• 6 years ago

I notice all the broken bits of rocket are in square panels.

That indicates the welds failed rather than the steel sheets in the explosion.

If you want to design something to be as strong as possible for the weight, you make the welds as strong as the sheets. In most cases, that means making the weld lines thicker than the rest, since the weld is typically formed in less ideal conditions so weaker.

There are tricks to doing that like zig-zag weld lines, overlapped sheets at the weld, etc.

Surprising spaceX hasn't done this, considering strength to weight is critical in rocketry.

gexla4• 6 years ago

Maybe this is by design. Maybe they are giving more thought to how they want the shell to blow apart rather than making it as strong as possible.

Once the thing decides it's going to explode, then the shell just needs an exit plan. The shell isn't going to hold anything together at this point.

maxerickson3• 6 years ago

Why would they prioritize behavior during catastrophic failure over the strength-weight ratio?

scollet2• 6 years ago

Can you provide references supporting thicker welds as well as reinforcing patterns? I have done introductory welding and am genuinely curious of the ramifications of both.

scollet2• 6 years ago

Addendum: preferably video instruction.

icegreentea2• 6 years ago

Two possibilities: the first is that for prototypes (even flight capable prototypes) they're optimizing for cost/iteration time more than performance. Given their apparent plan (which is just to build lots of them sand not worry too much if they blow up), going with simpler methods seems reasonable.

The other possibility is that they straight up are willing to eat the weight penalty, Starship is being put together with different constraints/assumptions than most other systems - like it's literally a stainless steel reusable rocket. Maybe their gaining something from that tradeoff that they prefer more.

I'm leaning towards it mostly being a prototype.

shireboy• 6 years ago

Rapid unscheduled disassembly.

risyachka• 6 years ago

You can't invent anything new without lots of fails. Let's hope they will blow them up as quickly as possible so we can see a flying one soon!

kerng2• 6 years ago

This thing should have blown up somewhere during launch, not while parked basically. People not happy.

SpaceX Starship SN4 launch vehicle prototype explodes after static engine test

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