Breaching

There are points at edges of star systems that allow dramatically accelerated travel to another warp point located near another star. This travel requires opening a "breach", a shortcut between two points in space, the process of opening one includes using sensitive, expensive machinery and expending significant amount of energy and time, depending on how big breach should be and how stable. Location of stars accessible by bridge is usually not possible to assess, either because they are too far to compare with EM sensors or perhaps completely unaccessible otherwise.