Terry... I think it is just engineering....

The human ribosome is a biological example of self-replicating nano-technology... so such is not science fiction.

We can use a laser the size of a solar system to columnate a beam of energy to power a space ship less that a gram in mass... there is a seperate trick for slowing down on other side.

Micro-meteors in intersteller vaccum are exceedingly rare, still they exist. And each one will completely destroy one of our micro machines... so they are spread out within the laser beam that powers them. They exist as duplicated parts of a complex machine that keep rebuilding itself from feedstock atoms that we are shooting at them along with the energy we send.

Thus our "copier" spacecraft is many microscopic components feeding off our umbilical cord ... and they replicate the destroyed parts over and over until it gets to its target. (whole mechanical organism keeps itself separated by spinning, and moves its own parts around internally by sequential electrostatic pushing and pulling)

with a replicator planted in a remote system, we simply just grow an energy collector at the remote star, then an environment that we can download into (maybe we only construct the single cell needed to kick off our species, or who knows what we create there). Yes it takes a hundred or so mellinia to inhabit the millions or billions of systems near us, but hey that is an eye-blink for the galaxy.

Yes this is colossal engineering by today's standards I agree, but there is no science fiction here, just colassal engineering. (just as the 100 story building or a fighter jet is colassal engineering by ancient standards.)

so what do you think? did I break some laws of physics here?