Maybe facet the mirrors so that the reflections would flicker in some something like Morse code. I imagine it would be very difficult to decipher and could onl

Maybe facet the mirrors so that the reflections would flicker in some something like Morse code. I imagine it would be very difficult to decipher and could only convey a few bytes though. Maybe just send a sealed capsule capable of re-entry into an orbit that would actually intersect earth in a few hundred thousand years. I doubt we're capable of that sort of precision though..