9 ms·

Regards to comments mentioning that this is three F9s strapped together: While this is somewhat true, the development of this program was apparently lot more di

Regards to comments mentioning that this is three F9s strapped together: While this is somewhat true, the development of this program was apparently lot more difficult than just tying them together. I remember Musk mentioning that they had underestimated the problem, the two additional boosters changed the dynamics significantly, and the core booster had to be redesigned to accommodate the new load parameters. Needless to say, I'm extremely excited to even see a static fire of this monster. Re-using boosters for your early development is pretty nice and efficient too I imagine.

paulmd 9y ago
> Re-using boosters for your early development is pretty nice and efficient too I imagine. It sounds good on paper but it's not easy in practice, see: the Russian N-1 moon rocket, which basically just took the R7 rocket and scaled it up with more engines. Turns out too many engines means too many points of failure, and the rocket never worked. https://en.wikipedia.org/wiki/N1_(rocket) https://en.wikipedia.org/wiki/N1_(rocket) Much like in computing, you can't substitute one oxen with a thousand chickens and expect the same outcome when you plow your field.
- valuearb 9y ago
  The N-1 failed for lots of reasons besides having so many engines. It's designer died before it was completed. It's primitive control systems were inadequate. It's funding was inadequate. SpaceX has already shown that with modern control systems, you can bundle a bunch of chickens together to plow a field. Having 9 engines has already helped them complete missions where one failed. The Falcon Heavy problem isn't scaling from 9 to 27 per se, it's building a new structure to handle all the new stresses that will occur, from the launch sequence to aerodynamic.
  - MPSimmons 9y ago
    The engines were also ablative and couldn't be tested together.
  - geerlingguy 9y ago
    And even the seemingly small things; like how to detach the side boosters, how to handle the vastly different aerodynamics when you don't have an interstage (nosecone instead), etc. It uses the same engines and very similar hardware, but there are so many new/not-flight-proven things on this rocket that it will be exciting, one way or another!
    - Pokepokalypse 9y ago
      Although, Boeing has proven the concept with Delta IV heavy, (and, I think there are a few other precursors, as well, including STS). So this isn't completely new territory.
- mulmen 9y ago
  I believe GP means literally re-using boosters that flew in space, not just the design.
- greglindahl 9y ago
  All supercomputing is now done with armies of chickens. It was a great saying when Cray said it, but the future was not what he imagined.
  - paulmd 9y ago
    Armies of chickens today would be something like ARM server chips, which have been touted for a long time but have perpetually stalled out precisely because replacing one powerful core with a dozen weak cores doesn't work. Even for commodity tasks, but especially when you throw the need for interconnect scalability into the mix. Don't make the mistake of thinking that a large system is implicitly using weaker processors. They're as powerful as we can make them, some tasks just need a lot of them.
- CPLX 9y ago
  If you can control the chickens, anything is possible.
  - troymc 9y ago
    Wow, that's my new motto!
ilogik 9y ago
Also, my understanding is that initially there was supposed to be a corss-feed system that would increase the total delta-V considerably, but it isn't ready yet
- AshleyGrant 9y ago
  That was initially the plan. It proved too complex and has since been dropped from the design. It won't be coming back. Which is too bad, because it would be really awesome if they had managed to make it work.
  - garmaine 9y ago
    Do you have a source?
    - AshleyGrant 9y ago
      https://twitter.com/elonmusk/status/726561442636263425 https://twitter.com/elonmusk/status/726561442636263425
      - 0xffff2 9y ago
        That doesn't imply that cross-feed isn't coming back, only that it isn't needed for the capabilities Musk posted.
        AshleyGrant 9y ago
        While that single statement might not imply that it's gone for good, everything Elon and SpaceX have publicly stated leads one to the conclusion that it isn't ever going to happen. Heck, Falcon Heavy has turned out to be a much larger engineering problem than originally thought even without asparagus staging (cross-feed) due to issues with reinforcing the center core to handle the loads from the side cores. Based on Musk's latest presentation regarding BFR, it seems that Falcon Heavy will be a somewhat short-lived launch platform. Then again, with SpaceX, plans change early and often...
jczhang 9y ago
Does anyone know how they keep it NOT moving when doing a static fire of something like this?
- nickik 9y ago
  There are clamps in the launch pad that hold the rocket down. This is easier then one would think because the rocket is fuelled and the engines already have a hard time living the rocket at all. They use the same launch pad during launch and the clamps only release when the computer has made sure all engines have correctly stared and are running correctly. Check out the video from RocketLab when they had a launch abort to see a example of this.

paulmd 9y ago

> Re-using boosters for your early development is pretty nice and efficient too I imagine. It sounds good on paper but it's not easy in practice, see: the Russian N-1 moon rocket, which basically just took the R7 rocket and scaled it up with more engines. Turns out too many engines means too many points of failure, and the rocket never worked. https://en.wikipedia.org/wiki/N1_(rocket) https://en.wikipedia.org/wiki/N1_(rocket) Much like in computing, you can't substitute one oxen with a thousand chickens and expect the same outcome when you plow your field.

valuearb 9y ago
The N-1 failed for lots of reasons besides having so many engines. It's designer died before it was completed. It's primitive control systems were inadequate. It's funding was inadequate. SpaceX has already shown that with modern control systems, you can bundle a bunch of chickens together to plow a field. Having 9 engines has already helped them complete missions where one failed. The Falcon Heavy problem isn't scaling from 9 to 27 per se, it's building a new structure to handle all the new stresses that will occur, from the launch sequence to aerodynamic.
- MPSimmons 9y ago
  The engines were also ablative and couldn't be tested together.
- geerlingguy 9y ago
  And even the seemingly small things; like how to detach the side boosters, how to handle the vastly different aerodynamics when you don't have an interstage (nosecone instead), etc. It uses the same engines and very similar hardware, but there are so many new/not-flight-proven things on this rocket that it will be exciting, one way or another!
  - Pokepokalypse 9y ago
    Although, Boeing has proven the concept with Delta IV heavy, (and, I think there are a few other precursors, as well, including STS). So this isn't completely new territory.
mulmen 9y ago
I believe GP means literally re-using boosters that flew in space, not just the design.
greglindahl 9y ago
All supercomputing is now done with armies of chickens. It was a great saying when Cray said it, but the future was not what he imagined.
- paulmd 9y ago
  Armies of chickens today would be something like ARM server chips, which have been touted for a long time but have perpetually stalled out precisely because replacing one powerful core with a dozen weak cores doesn't work. Even for commodity tasks, but especially when you throw the need for interconnect scalability into the mix. Don't make the mistake of thinking that a large system is implicitly using weaker processors. They're as powerful as we can make them, some tasks just need a lot of them.
CPLX 9y ago
If you can control the chickens, anything is possible.
- troymc 9y ago
  Wow, that's my new motto!

ilogik 9y ago

Also, my understanding is that initially there was supposed to be a corss-feed system that would increase the total delta-V considerably, but it isn't ready yet

AshleyGrant 9y ago
That was initially the plan. It proved too complex and has since been dropped from the design. It won't be coming back. Which is too bad, because it would be really awesome if they had managed to make it work.
- garmaine 9y ago
  Do you have a source?
  - AshleyGrant 9y ago
    https://twitter.com/elonmusk/status/726561442636263425 https://twitter.com/elonmusk/status/726561442636263425
    - 0xffff2 9y ago
      That doesn't imply that cross-feed isn't coming back, only that it isn't needed for the capabilities Musk posted.
      - AshleyGrant 9y ago
        While that single statement might not imply that it's gone for good, everything Elon and SpaceX have publicly stated leads one to the conclusion that it isn't ever going to happen. Heck, Falcon Heavy has turned out to be a much larger engineering problem than originally thought even without asparagus staging (cross-feed) due to issues with reinforcing the center core to handle the loads from the side cores. Based on Musk's latest presentation regarding BFR, it seems that Falcon Heavy will be a somewhat short-lived launch platform. Then again, with SpaceX, plans change early and often...

jczhang 9y ago

Does anyone know how they keep it NOT moving when doing a static fire of something like this?

nickik 9y ago
There are clamps in the launch pad that hold the rocket down. This is easier then one would think because the rocket is fuelled and the engines already have a hard time living the rocket at all. They use the same launch pad during launch and the clamps only release when the computer has made sure all engines have correctly stared and are running correctly. Check out the video from RocketLab when they had a launch abort to see a example of this.