For years now, I’ve been following what’s happening in the field of interstellar travel. Not closely, but close enough to know what kinds of technology are out there. Paul Gilster’s blog Centauri Dreams is a good resource.
Because of the large distances involved, and because of the energy needed to accelerate a probe to the speed required to cover them, probes need to be light, no more than a few grams. Previous designs proposed propelling the tiny probed using high energy laser beams, but that would be costly. A new design by David Kipping proposes to use the sun’s radiation to spin up a slingshot, kind of like a giant Crookes radiometer. It seems to be an entirely new idea, but if it’s feasible remains to be seen.
Nehaveigur 