3 ms·

I could be wrong, but these two things don’t seem like they’re really that comparable. Apollo was certainly a monumental engineering achievement, but did it req

I could be wrong, but these two things don’t seem like they’re really that comparable. Apollo was certainly a monumental engineering achievement, but did it require that we 100X the state of the art efficiency of some critical tech?

JumpCrisscross 2y ago
> Apollo was certainly a monumental engineering achievement, but did it require that we 100X the state of the art efficiency of some critical tech? One order of magnitude in propulsion. When Kennedy made his “We choose to go to the Moon” speech [1], our most powerful rocket was the Saturn I. Its H-1 engines thrusted at 200k lbf [2]. The Saturn V’s F-1s did 1.5mm lbf [3]. (The Saturn V, similarly, could lift an order of magnitude more mass to LEO than the Saturn I.) It wouldn’t surprise me to find 100x increases in some material’s performance, et cetera. [1] https://en.m.wikipedia.org/wiki/We_choose_to_go_to_the_Moon https://en.m.wikipedia.org/wiki/We_choose_to_go_to_the_Moon [2] https://en.m.wikipedia.org/wiki/Rocketdyne_H-1 https://en.m.wikipedia.org/wiki/Rocketdyne_H-1 [3] https://en.m.wikipedia.org/wiki/Rocketdyne_F-1 https://en.m.wikipedia.org/wiki/Rocketdyne_F-1
- bandyaboot 2y ago
  So I specifically called out efficiency because 100X’ing your thrust is about scaling up technology. That generally involves solving engineering problems—figuring how to control vibration resonance would be one example in the case of the Saturn. 100X’ing efficiency, it seems to me, is another animal entirely—it’s often about legitimate scientific breakthroughs. Like going in, you don’t even know for sure of its possible.
  - JumpCrisscross 2y ago
    > 100X’ing efficiency, it seems to me, is another animal entirely Saturn V had a specific impulse of 263 s [1]. NSTAR did 3,000 s [2]. That’s an order of magnitude improvement in efficiency in 30 years of low-effort improvements. Starship should demonstrate in-orbit refuelling next year. That’s another 10x technology. Add on a solar sail and you’re in the realm of two orders of magnitude of efficiency gains with known technologies. (Three from Apollo.) [1] https://en.m.wikipedia.org/wiki/Saturn_V https://en.m.wikipedia.org/wiki/Saturn_V [2] https://en.m.wikipedia.org/wiki/NASA_Solar_Technology_Application_Readiness https://en.m.wikipedia.org/wiki/NASA_Solar_Technology_Applic...

JumpCrisscross 2y ago

> Apollo was certainly a monumental engineering achievement, but did it require that we 100X the state of the art efficiency of some critical tech? One order of magnitude in propulsion. When Kennedy made his “We choose to go to the Moon” speech [1], our most powerful rocket was the Saturn I. Its H-1 engines thrusted at 200k lbf [2]. The Saturn V’s F-1s did 1.5mm lbf [3]. (The Saturn V, similarly, could lift an order of magnitude more mass to LEO than the Saturn I.) It wouldn’t surprise me to find 100x increases in some material’s performance, et cetera. [1] https://en.m.wikipedia.org/wiki/We_choose_to_go_to_the_Moon https://en.m.wikipedia.org/wiki/We_choose_to_go_to_the_Moon [2] https://en.m.wikipedia.org/wiki/Rocketdyne_H-1 https://en.m.wikipedia.org/wiki/Rocketdyne_H-1 [3] https://en.m.wikipedia.org/wiki/Rocketdyne_F-1 https://en.m.wikipedia.org/wiki/Rocketdyne_F-1

bandyaboot 2y ago
So I specifically called out efficiency because 100X’ing your thrust is about scaling up technology. That generally involves solving engineering problems—figuring how to control vibration resonance would be one example in the case of the Saturn. 100X’ing efficiency, it seems to me, is another animal entirely—it’s often about legitimate scientific breakthroughs. Like going in, you don’t even know for sure of its possible.
- JumpCrisscross 2y ago
  > 100X’ing efficiency, it seems to me, is another animal entirely Saturn V had a specific impulse of 263 s [1]. NSTAR did 3,000 s [2]. That’s an order of magnitude improvement in efficiency in 30 years of low-effort improvements. Starship should demonstrate in-orbit refuelling next year. That’s another 10x technology. Add on a solar sail and you’re in the realm of two orders of magnitude of efficiency gains with known technologies. (Three from Apollo.) [1] https://en.m.wikipedia.org/wiki/Saturn_V https://en.m.wikipedia.org/wiki/Saturn_V [2] https://en.m.wikipedia.org/wiki/NASA_Solar_Technology_Application_Readiness https://en.m.wikipedia.org/wiki/NASA_Solar_Technology_Applic...