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Nuclear rockets are a dramatic improvement on chemical rockets. We've already built those. Ion engines are a dramatic improvement on chemical rockets. We are cu
by stcredzero 8y ago
Nuclear rockets are a dramatic improvement on chemical rockets. We've already built those. Ion engines are a dramatic improvement on chemical rockets. We are currently using those. Robert Forward also calculated that almost any conceivable mission in the solar system could be accomplished by an antimatter rocket with only a 3/5ths fuel fraction. Fusion rockets would be a somewhat watered-down version of that. (Though, nowhere near what's shown on The Expanse with Epstein Drives.)
Beamed propulsion throws out the rocket equation altogether, as do light sails.
- vkou 8y agoThe problem with beamed propulsion is that you still need a rocket, or some equivalent thereof to stop going, whenever you get to your destination. Not an issue for flybys, but an issue if you want to get into an orbit.
- mLuby 8y agoOr just a mirror ahead of the spacecraft!
- stcredzero 8y agoThe problem with beamed propulsion is that you still need a rocket, or some equivalent thereof to stop going, whenever you get to your destination. False. Robert Forward has a technique for deceleration for interstellar lightsail craft, which is described in Rocheworld and one of his science books. Magsails using beamed particle propulsion can also exploit the interstellar medium to decelerate without onboard fuel. Not an issue for flybys, but an issue if you want to get into an orbit. Carrying a small rocket for a circularization burn is vastly cheaper than a 1st stage. This is covered in Jordin Kare's modular laser launch proposal, and this technique was also considered for Bull's light gas space gun. Those can produce launch economics approaching those of space elevators.
- Alupis 8y ago> False. Robert Forward has a technique Sorry, but you're citing a science fiction author as proposing a credible method, yet don't even state what that method is. Yes, I know Robert Forward used to work in aerospace, but his fiction writings are... fiction. He's been out of the industry since 2002 and a hand-wavy "he has a technique" doesn't strike me as being particularly credible.
- stcredzero 8y agoSorry, but you're citing a science fiction author as proposing a credible method Sorry, but he was also a noted physicist. yet don't even state what that method is. http://lmgtfy.com/?q=Robert+Forward+laser+sail+deceleration http://lmgtfy.com/?q=Robert+Forward+laser+sail+deceleration
- abecedarius 8y agoSkyhooks (rotating tethers). Energetically they're like an elevator with a counterweight. They're also another non-rocket answer for the outbound leg.
- stcredzero 8y agoI think Venus might have an economic edge in the early days of the trans-Solar System economy, because the whole of its civilization will be floating at high altitude. Even without orbital rings and space elevators, everything will have very cheap access to space through skyhooks.
- abecedarius 8y agoLots of solar power, too, and lightsails and magsails have more to work with. (I was thinking of free-space skyhooks, exchanging momentum between inbound and outbound trips, but the ones for planets are also cool. Just harder when the planet is heavy like Earth and Venus.)