3 ms·

is this really more efficient than just launching the rocket normally with chemicals? the article doesn't really go into detail but alludes to the answer to my

is this really more efficient than just launching the rocket normally with chemicals? the article doesn't really go into detail but alludes to the answer to my question being "yes". I guess the idea is: you can spin a smaller rocket which requires energy EnergySml. Alternatively you could have a larger rocket which requires EnergyLrg to get out of the atmosphere. So EnergySml + Fuel in rocket to leave atmosphere << EnergyLrg (which is launch + leave atmosphere)? --- other questions I had were: - wouldn't the rocket being spun have to be heavier than the equivalently sized chemical rocket because it has to be able to survive being flung around in a centrifuge?

walrus01 5y ago
the important thing I think is that your energy-consuming device (the spinny part) can be huge and heavy and remain on the ground, so it doesn't need to be designed like a rocket first stage. Even if it's actually really inefficient in terms of watt-hours used to spin the thing, doesn't matter.
retrac 5y ago
You don't have to lift the fuel. A huge proportion of the fuel in a rocket's first stage is used to lift the fuel in the first stage off the ground for the first few hundred metres of flight. It's almost diabolically inefficient. Using a really big cannon, not entirely unlike in the Jules Verne novel, has been investigated seriously. It has similar efficiency benefits. Some limits on what can survive the acceleration though: https://en.m.wikipedia.org/wiki/Project_HARP https://en.m.wikipedia.org/wiki/Project_HARP
- FpUser 5y ago
  I knew this would come up in here. Gerard Bull was an amazing character. Unfortunately he was screwed by few governments and at the end he was assassinated (presumably by Mossad).
kumarvvr 5y ago
> you can spin a smaller rocket That could be extremely complex, unless (perhaps) the rocket using solid boosters, in which case, you are spinning a highly volatile mega bomb.
- __m 5y ago
  They ARE spinning a rocket
spoonjim 5y ago
You can use ground-based energy to spin the rocket, which is vastly cheaper and doesn't need to be lifted.

walrus01 5y ago

the important thing I think is that your energy-consuming device (the spinny part) can be huge and heavy and remain on the ground, so it doesn't need to be designed like a rocket first stage. Even if it's actually really inefficient in terms of watt-hours used to spin the thing, doesn't matter.

retrac 5y ago

You don't have to lift the fuel. A huge proportion of the fuel in a rocket's first stage is used to lift the fuel in the first stage off the ground for the first few hundred metres of flight. It's almost diabolically inefficient. Using a really big cannon, not entirely unlike in the Jules Verne novel, has been investigated seriously. It has similar efficiency benefits. Some limits on what can survive the acceleration though: https://en.m.wikipedia.org/wiki/Project_HARP https://en.m.wikipedia.org/wiki/Project_HARP

FpUser 5y ago
I knew this would come up in here. Gerard Bull was an amazing character. Unfortunately he was screwed by few governments and at the end he was assassinated (presumably by Mossad).

kumarvvr 5y ago

> you can spin a smaller rocket That could be extremely complex, unless (perhaps) the rocket using solid boosters, in which case, you are spinning a highly volatile mega bomb.

__m 5y ago
They ARE spinning a rocket

spoonjim 5y ago

You can use ground-based energy to spin the rocket, which is vastly cheaper and doesn't need to be lifted.