You can't intercept an interstellar object from a loitering orbit around the sun, with something that has basically zero delta-v (in terms of this context) onbo

You can't intercept an interstellar object from a loitering orbit around the sun, with something that has basically zero delta-v (in terms of this context) onboard. The loitering orbit, by necessity, has a fairly tightly constrained velocity vector, and the interstellar object, by virtue of having escape velocity from our sun, must have a much higher velocity vector by a certain large number of kilometers per second at a minimum, basically unbounded on the upper end. By the time you have something like a nuclear rocket in space that has the requisite delta-v, there becomes no particular reason to station it around the sun, since you can get to the right vectors from anywhere in the system.