3 ms·

Excuse my ignorance but... Wouldn't the energy required to launch something from a slingshot be the same as using a propulsion engine?

• truncular 5y ago
  Roughly. But in theory it is easier/cheaper to harness that energy in a ground based system (like spinlaunch) than with a complex and traditionally unreusable rocket engine.
• mcguire 5y ago
  Yes-ish. If you replace the first stage of a rocket with one o' these things, you don't need to lift the first stage's fuel and engines.
• jfengel 5y ago
  No, because you don't have to carry your fuel with you. A rocket engine is subject to the Rocket Equation, where the amount of fuel you need is exponential in the amount of velocity you're trying to acquire. If you can impart all of that energy on the ground, you don't have to use 90% of the fuel to lift 10% of the mass halfway, and then 90% of that to get you the rest of the way, meaning your rocket outweighs your payload by almost 100x. https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation In this, the fuel all gets to remain on the ground. It's a bit like if you could take your capsule and put it on top of a giant exploding pile, getting all its speed all at once. You'd need a lot less fuel that way... except you wouldn't survive the explosion. The energy savings of this are great. Everything else is completely bonkers.