SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident • Hacker News Board

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

#141

Post by Rebelgecko » Thu, Nov 21, 2019, 5:36 AM UTC

Diederich wrote: post #123

Rebelgecko wrote: post #106

Earlier quoted context omitted.

>they dont seem to be trying to "spin" anything Compare their statements about the cause of the CRS-7 explosion to NASA's.

I dug around and didn't find an official SpaceX statement. The cause was a poorly constructed struct they bought from a 3rd party company. > Compare their statements about the cause of the CRS-7 explosion to NASA's. Did NASA's and SpaceX's statements differ in content?

SpaceX statement: https://www.spacex.com/news/2015/07/20/crs-7-investigation-u...

NASA accident investigation report: https://www.nasa.gov/sites/default/files/atoms/files/public_...

TBF the NASA report came much later than the SpaceX explanation. However it might be of interest to compare:

SpaceX explanation of why looking at the right telemetry is hard vs "Technical Finding 4" from NASA.

SpaceX explanation of the strut's "certifications" and max load vs "Technical Finding 1" (and the longer explanation earlier in the document, you can do a control-f for "Where the IRT differs with SpaceX is in regards to the initiating cause")

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

#142

Post by soperj » Thu, Nov 21, 2019, 5:37 AM UTC

kev009 wrote: post #121

lopmotr wrote: post #116

Earlier quoted context omitted.

That response doesn't make sense (normal people can risk lives but billionaires can't?). What does make sense is the fact that daily driving produces lots of economic value in the short term which manned space travel doesn't. So it's worth killing some drivers but not worth killing some astronauts. But that's still not obviously the right conclusion. Space travel has the potential for much greater value further in th…

It's completely orthogonal. By all means fix the externalities of internal combustion engines. Intelligent people in NASA realized unmanned vehicles can conduct almost all important space research and business in the near future. There is no reason to jump the gun and do it with the lack of quality the software industry champions and is known for. If the mission of manned space flight is simply to inspire people, the…

And people could take all their meetings from home.

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

#143

Post by jcims » Thu, Nov 21, 2019, 5:52 AM UTC

CydeWeys wrote: post #133

jcims wrote: post #129

Earlier quoted context omitted.

If it's filled with liquid.

I haven't known soda cans to be filled with anything else. And it's not like rockets are filled with air; they're filled with liquid fuels.

Depends. Falcon 9 is almost entirely filled with helium when it lands.

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

#144

Post by jcims » Thu, Nov 21, 2019, 5:52 AM UTC

CydeWeys wrote: post #66

db48x wrote: post #60

Earlier quoted context omitted.

At least when filled and pressurized.

An empty soda can is much stronger relative to its weight than a full one.

Evidence - https://www.youtube.com/watch?v=YP_UBNwEoGs

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

#145

Post by tus88 » Thu, Nov 21, 2019, 6:00 AM UTC

lmilcin wrote: post #26

hsnewman wrote: post #6

And that's why they are testing it.

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 skyscrap…

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

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

#146

Post by mattrp » Thu, Nov 21, 2019, 6:09 AM UTC

bdamm wrote: post #79

mattrp wrote: post #53

Earlier quoted context omitted.

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

Also, by paying the neighbors 3x their property value to buy out their homes.

Yeah I know ... my comment was in jest ....but note the dateline below was yesterday...

https://www.krgv.com/news/spacex-extends-buyout-offer-deadli...

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

#147

Post by trixie_ » Thu, Nov 21, 2019, 6:17 AM UTC

kev009 wrote: post #92

newnewpdro wrote: post #63

Earlier quoted context omitted.

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.

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.

I laugh out loud at armchair engineers who think they have any real insight into a massive engineering development program like Starship.

SpaceX has proven themselves over and over again of being more than capable of achieving their goals in light of people like you.

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

#148

Post by errantspark » Thu, Nov 21, 2019, 7:03 AM UTC

dehrmann wrote: post #138

errantspark wrote: post #69

Earlier quoted context omitted.

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...

How does that compare to commercial airplanes?

I'm guessing something in the 3:2 range on payload to structure ratio.

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

#149

Post by iamgopal » Thu, Nov 21, 2019, 7:18 AM UTC

lmilcin wrote: post #26

hsnewman wrote: post #6

And that's why they are testing it.

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 skyscrap…

At least the pump is working and generating pressure.

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

#150

Post by kristianp » Thu, Nov 21, 2019, 7:33 AM UTC

zionic wrote: post #14

andrewflnr wrote: post #11

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.

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.

Is the mk2 in the parallel location?