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And that's why they are testing it.

mdorazio 7y 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.
cma 7y 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.
- cma 7y 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-shotwell-space-ted-conference-interview https://www.vox.com/2018/4/11/17227036/flight-spacex-gwynne-... Moon 2023: https://www.scientificamerican.com/article/spacex-plans-to-fly-humans-around-the-moon-in-2023/ https://www.scientificamerican.com/article/spacex-plans-to-f...
  - ncmncm 7y ago
    It's amazing they know the exact month already.
pardavis 7y 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 7y ago
  Ah so this wasn't an accident? They needed to know the pressure limits so they purposely blew the bulkhead?
  - CydeWeys 7y ago
    Unlikely. But they have learned to be more careful with the welds going forward. Though, admittedly, they only used panel welding on the first prototype and have already switched it up for the second one.
  - deleted 7y ago
    [deleted]
  - hsnewman 7y ago
    It clearly was an accident, why would they put 3 rocket engines in it if they were going to stress test the tank?
- lmilcin 7y 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.
- taneq 7y ago
  Good news, everyone!
lmilcin 7y 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.
- DennisP 7y ago
  I think SpaceX has proven they know how to design rockets. But they are newcomers to building rockets from welded steel.
  - walrus01 7y ago
    It is my understanding that the pressure vessels are carbon fiber composites. The skin is steel.
    - gpm 7y ago
      The skin is the pressure vessel, double walls are a waste of valuable mass. They gave up on carbon fiber awhile ago. *I think they still use small composite overwrapped pressure vessels for fluids they need less of than CH4 and O2, just referring to giving up on carbon for the main tanks.
    - nwallin 7y ago
      Do you have a source? My understanding is that the skin is the pressure vessel. The reason for going with stainless steel at all is because it maintains integrity at high temperature. Carbon fiber does not. So a stainless steel combined heatsink and structure can maintain integrity at 1000C or whatever, while carbon fiber+ceramic heatshield will need to hold temperatures below 400C or whatever. And even though the fiber structure is much, much lighter, the amount of heat protection required is massive. And the stainless steel "cheats" by performing double duty. And you get a second free lunch because the heat protection requirements are slimmer. It wouldn't be the first time I've been wrong today though. Nor the second.
Davesjoshin 7y 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.
- mattrp 7y ago
  That’s one way to get the neighbors to move!
  - bdamm 7y ago
    Also, by paying the neighbors 3x their property value to buy out their homes.
    - mattrp 7y ago
      Yeah I know ... my comment was in jest ....but note the dateline below was yesterday...<raised eyebrow> https://www.krgv.com/news/spacex-extends-buyout-offer-deadline-again-as-homeowners-continue-to-fight/ https://www.krgv.com/news/spacex-extends-buyout-offer-deadli...
- vkou 7y 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_ 7y ago
I mean, sure, but they certainly wanted to get more data out of it than they did. This is a setback.

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.

cma 7y 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.

cma 7y 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-shotwell-space-ted-conference-interview https://www.vox.com/2018/4/11/17227036/flight-spacex-gwynne-... Moon 2023: https://www.scientificamerican.com/article/spacex-plans-to-fly-humans-around-the-moon-in-2023/ https://www.scientificamerican.com/article/spacex-plans-to-f...
- ncmncm 7y ago
  It's amazing they know the exact month already.

pardavis 7y 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 7y ago
Ah so this wasn't an accident? They needed to know the pressure limits so they purposely blew the bulkhead?
- CydeWeys 7y ago
  Unlikely. But they have learned to be more careful with the welds going forward. Though, admittedly, they only used panel welding on the first prototype and have already switched it up for the second one.
- deleted 7y ago
  [deleted]
- hsnewman 7y ago
  It clearly was an accident, why would they put 3 rocket engines in it if they were going to stress test the tank?
lmilcin 7y 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.
taneq 7y ago
Good news, everyone!

lmilcin 7y 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.

DennisP 7y ago
I think SpaceX has proven they know how to design rockets. But they are newcomers to building rockets from welded steel.
- walrus01 7y ago
  It is my understanding that the pressure vessels are carbon fiber composites. The skin is steel.
  - gpm 7y ago
    The skin is the pressure vessel, double walls are a waste of valuable mass. They gave up on carbon fiber awhile ago. *I think they still use small composite overwrapped pressure vessels for fluids they need less of than CH4 and O2, just referring to giving up on carbon for the main tanks.
  - nwallin 7y ago
    Do you have a source? My understanding is that the skin is the pressure vessel. The reason for going with stainless steel at all is because it maintains integrity at high temperature. Carbon fiber does not. So a stainless steel combined heatsink and structure can maintain integrity at 1000C or whatever, while carbon fiber+ceramic heatshield will need to hold temperatures below 400C or whatever. And even though the fiber structure is much, much lighter, the amount of heat protection required is massive. And the stainless steel "cheats" by performing double duty. And you get a second free lunch because the heat protection requirements are slimmer. It wouldn't be the first time I've been wrong today though. Nor the second.

Davesjoshin 7y 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.

mattrp 7y ago
That’s one way to get the neighbors to move!
- bdamm 7y ago
  Also, by paying the neighbors 3x their property value to buy out their homes.
  - mattrp 7y ago
    Yeah I know ... my comment was in jest ....but note the dateline below was yesterday...<raised eyebrow> https://www.krgv.com/news/spacex-extends-buyout-offer-deadline-again-as-homeowners-continue-to-fight/ https://www.krgv.com/news/spacex-extends-buyout-offer-deadli...
vkou 7y 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_ 7y ago

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