This is a variation of the old Starwisp idea from 1985: https://en.wikipedia.org/wiki/Starwisp https://en.wikipedia.org/wiki/Starwisp tl;dr: a lightweight (ab

This is a variation of the old Starwisp idea from 1985: https://en.wikipedia.org/wiki/Starwisp https://en.wikipedia.org/wiki/Starwisp tl;dr: a lightweight (about 1kg) vehicle made out of carbon wire mesh. It acts as a microwave mirror. You both use this for propulsion, by blasting it with microwaves from a Sol-system maser cannon, and for data recovery; its sensors cause the reflected microwave signal to be perturbed based on what its sensors see. So, you accelerate them (in bulk) at about 2G up to .1c. You ignore it until it's about 80% of the way there, and then for fire the maser at it again; the beam reaches the starwisp as it passes through the target system and powers the sensors. A few years later you read back the return signal. There were a whole bunch of technical problems with it, not least how to build a microwave lens 560km across, but it's still vastly more plausible than trying to push steel cans across the interstellar gulf. I'd be really interested to see if this version works.