OK so I'm writing a story (or I will be after I finish exams November 5) and it will involve the first interstellar craft. But I want it to be practical, not something of PURE science fiction with an explanation no better than saying it was magical. How do you think early interstellar craft will work? I'm trying to get it so that it can travel with an average speed of at least 0.5C, though if it's a constant acceleration craft then that means it reaches the speed of light. Perhaps it won't be a constant acceleration craft then. How about it gets arbitrarily close to the speed of light and then stays there for a while before slowing itself down again?
The plan is that I want it get to Epsilon Eridani (about 10 light years away) in 20 years or under.
So far my plan is that it will be a two-stage-non-rocket, using a nuclear blast in an Orion type fashion:
http://en.wikipedia.org/wiki/Project_Or ... propulsion)
This will start it off, but the Orion concept's maximum velocity is in the single digit, or less, percentages of c, so that will take too long for the story. So what I imagine is that it will shed off a lot of it's mass once the ship reaches the top speed the Orion propulsion can get it, as an Orion craft needs a lot of mass to avoid lethal accelerations (or you could just reduce the force of the explosion I suppose) and because the next form of propulsion requires minimal mass. A Bussard ramjet:
http://en.wikipedia.org/wiki/Bussard_ramjetSo now you'll have the magnetic sail using the solar wind to push it along (and as long as they're in the heliosphere they might use solar sails as well, minimal mass involved there) before leaving and switching the sails forward to pull interstellar medium into a fusion generator.
So that's the plan so far, but what do you guys think? Have you got some more original ideas for getting a craft across the interstellar 'void'?