5 ms·

>immediately So far this hasn't been shown even on much simpler Falcons. The barge gives quite some energy advantage for not having to boost back. Ideally the

>immediately So far this hasn't been shown even on much simpler Falcons. The barge gives quite some energy advantage for not having to boost back. Ideally they'd build a capesize kinda barge with chopsticks to catch it in the ocean, then perhaps service what they have to while it's steaming back.

literalAardvark 2y ago
Hasn't been shown because they're not meant to be immediately reusable. Spaceship and/or super heavy are (I don't remember the details).
- jojobas 2y ago
  I'll believe it when I see it.
  - avmich 2y ago
    It would be good because there are many people who, roughly, refuse to believe their own eyes and keep moving goalposts, misrepresenting what they said or meant earlier, inventing additional conditions, changing their mind etc. If you would honestly believe that Starship can fly frequently when you see it flying frequently, you're already ahead of some.
    - jiggawatts 2y ago
      I remember when people doubted that the full-flow staged combustion methalox engines could work... until SpaceX showed over a hundred of them working now. Then the ULA CEO Tory Bruno claiming that the SpaceX photos of the first Raptor 3 were “partially assembled”, to which Gwynne Shotwell replied with this: https://x.com/Gwynne_Shotwell/status/1821674726885924923?t=vT35PMKOMiUfWg6hun2f_A https://x.com/Gwynne_Shotwell/status/1821674726885924923?t=v...
      - avmich 2y ago
        I'd consider that cheating on the Gwynne side. It could be argued if chamber tilting mechanism is part of the engine - after all, it was added separately to NK-33 - but surely for Raptors it's considered an integral part, the fire test was then a test of chamber, not the engine :) . Though Gwynne had to answer positively, having little good choice.
        timschmidt 2y ago
        The outer ring of engines on Superheavy do not tilt. They're rigidly mounted and exclude even the engine start hardware which is contained in the launch mount, further reducing weight. And they're only used during liftoff, not for boostback or landing.
        avmich 2y ago
        Raptor is non-functional without tilting. That is, it's possible to build rocket where all Raptors are fixed, but that defeats some ideas of Raptors. And I haven't seen tilt mechanisms considered parts of the rocket. So, while engines without tilting have been used - e.g. NK-15 - Raptors aren't from that category.
        modeless 2y ago
        Raptor is used in a non-tilting configuration on both the booster and ship. You could certainly design a rocket to get to space with only non-tilting raptors, if you wanted. It would be silly to consider it incomplete without tilt, even if Starship does have some tilting ones too. Consider it two variants if you like, both complete on their own.
        timschmidt 2y ago
        Differential thrust has been used to steer rockets for decades, and raptor has the sort of deep throttling capability required for it. Tilting is absolutely not required for anything but landing.
modeless 2y ago
Falcon 9 wasn't designed for immediate reuse. Immediate reuse is just a theory right now, but SpaceX has an excellent track record of turning their theories into reality. SpaceX did purchase some oil rigs with the intention to turn them into launch platforms, but later abandoned the idea. It's probably something they will return to later once Starship is flying regularly. You're right that avoiding the boostback burn is a big advantage. But maybe they don't need to bring the booster back after it lands on a platform, it can just launch again from there. Maybe they could have a bucket brigade of launch platforms ringing the Earth!
- ethbr1 2y ago
  The oil rig idea is brilliant, especially for cargo flights. I.e. the bulk of near / intermediate term launches Far fewer people care if you "oops" an unmanned rig in the ocean.
  - CableNinja 2y ago
    The issue is logistics, and in this case isnt an easy solve. You have to get fuel, and the rocket, out to a pad in the ocean, and have to deal with a rocket lift on varying conditions. If you dont want to do most of that, then the only option is putting your manufacturing on the rig too, which negates lifting a rocket, but instead makes the rig huge, and requires having a train of ships in and out 24/7 to keep it supplied. There was even a company in the late 90s that tried oil rig launch platforms and ultimately abandoned it.
    - ethbr1 2y ago
      Most heavy lift is transported by barge over water anyway. Since the 2 stages of Starship aren't intended to be road mobile, due to size, there's no transportation benefit to being land-accessible. So really the main concern is piping propellant... but afaik some rigs off the shallow coast of Texas are directly piped to land? The main benefit you get is terrifying the FAA et al. less, as the consequences of a missed catch are now out in the ocean.
- 2y ago

literalAardvark 2y ago

Hasn't been shown because they're not meant to be immediately reusable. Spaceship and/or super heavy are (I don't remember the details).

jojobas 2y ago
I'll believe it when I see it.
- avmich 2y ago
  It would be good because there are many people who, roughly, refuse to believe their own eyes and keep moving goalposts, misrepresenting what they said or meant earlier, inventing additional conditions, changing their mind etc. If you would honestly believe that Starship can fly frequently when you see it flying frequently, you're already ahead of some.
  - jiggawatts 2y ago
    I remember when people doubted that the full-flow staged combustion methalox engines could work... until SpaceX showed over a hundred of them working now. Then the ULA CEO Tory Bruno claiming that the SpaceX photos of the first Raptor 3 were “partially assembled”, to which Gwynne Shotwell replied with this: https://x.com/Gwynne_Shotwell/status/1821674726885924923?t=vT35PMKOMiUfWg6hun2f_A https://x.com/Gwynne_Shotwell/status/1821674726885924923?t=v...
    - avmich 2y ago
      I'd consider that cheating on the Gwynne side. It could be argued if chamber tilting mechanism is part of the engine - after all, it was added separately to NK-33 - but surely for Raptors it's considered an integral part, the fire test was then a test of chamber, not the engine :) . Though Gwynne had to answer positively, having little good choice.
      - timschmidt 2y ago
        The outer ring of engines on Superheavy do not tilt. They're rigidly mounted and exclude even the engine start hardware which is contained in the launch mount, further reducing weight. And they're only used during liftoff, not for boostback or landing.
        avmich 2y ago
        Raptor is non-functional without tilting. That is, it's possible to build rocket where all Raptors are fixed, but that defeats some ideas of Raptors. And I haven't seen tilt mechanisms considered parts of the rocket. So, while engines without tilting have been used - e.g. NK-15 - Raptors aren't from that category.
        modeless 2y ago
        Raptor is used in a non-tilting configuration on both the booster and ship. You could certainly design a rocket to get to space with only non-tilting raptors, if you wanted. It would be silly to consider it incomplete without tilt, even if Starship does have some tilting ones too. Consider it two variants if you like, both complete on their own.
        timschmidt 2y ago
        Differential thrust has been used to steer rockets for decades, and raptor has the sort of deep throttling capability required for it. Tilting is absolutely not required for anything but landing.

modeless 2y ago

Falcon 9 wasn't designed for immediate reuse. Immediate reuse is just a theory right now, but SpaceX has an excellent track record of turning their theories into reality. SpaceX did purchase some oil rigs with the intention to turn them into launch platforms, but later abandoned the idea. It's probably something they will return to later once Starship is flying regularly. You're right that avoiding the boostback burn is a big advantage. But maybe they don't need to bring the booster back after it lands on a platform, it can just launch again from there. Maybe they could have a bucket brigade of launch platforms ringing the Earth!

ethbr1 2y ago
The oil rig idea is brilliant, especially for cargo flights. I.e. the bulk of near / intermediate term launches Far fewer people care if you "oops" an unmanned rig in the ocean.
- CableNinja 2y ago
  The issue is logistics, and in this case isnt an easy solve. You have to get fuel, and the rocket, out to a pad in the ocean, and have to deal with a rocket lift on varying conditions. If you dont want to do most of that, then the only option is putting your manufacturing on the rig too, which negates lifting a rocket, but instead makes the rig huge, and requires having a train of ships in and out 24/7 to keep it supplied. There was even a company in the late 90s that tried oil rig launch platforms and ultimately abandoned it.
  - ethbr1 2y ago
    Most heavy lift is transported by barge over water anyway. Since the 2 stages of Starship aren't intended to be road mobile, due to size, there's no transportation benefit to being land-accessible. So really the main concern is piping propellant... but afaik some rigs off the shallow coast of Texas are directly piped to land? The main benefit you get is terrifying the FAA et al. less, as the consequences of a missed catch are now out in the ocean.
2y ago