Allen Steele, in his book Coyote Frontier, talks about a stargate bridge that connects Earth with a distant planet. In fact, once two portals have been positioned and synchronized, vessels can jump almost immediately across the vast distances of space connecting them. Steele also suggested that the second ship was composed of the parts needed to construct the second portal gate, which could be built from these parts, once the ship had arrived at its destination. Could a starbridge be formed by creating a standing wave between two oppositely charged portals? http://www.physicsclassroom.com/Class/waves/u10l4b.cfm You might be able to fire a noble gas--like abundant argon (Ar)--from each end, from each portal, to create the necessary standing wave between them that creates the starbridge. Perhaps you could use the propulsion system, like VASMIR that uses argon for its propulsion, for the second portal. http://spaceflight.nasa.gov/shuttle/support/researching/aspl/vasimr.html I would also suggest that it might be possible to use the cantilever system of constructing such a bridge, so that you extend it as you go.