> it would by nature need to be capable of full self repair

Why? If we can accelerate a small city to 0.01g in a year, we can accelerate smaller packages to catch up with it once a year.

How is that package going to navigate, and then match velocity to dock?

Should be doable with beamed propulsion. Basically give each package a lightsail & you can have it maneuver when illuminated by laser arrays either in the home system or on the interstellar craft itself.

The beauty of this setup is that if you are really good at keeping the schedule, this can be all pre-computed. With time slots being allocated beforehand when the laser arrays send beams in a given direction & the packages (or the craft itself) just making really sure they stay in the beam & properly oriented when it arrives at the planed place and time.

Imagine the mythology that will develop on that general ship about the beamed packages.

> full self repair, with the shipped materials and energy, and with no wasted byproducts.

Isn’t this impossible? Doesn’t entropy preclude perfect ongoing repair?

> Isn’t this impossible? Doesn’t entropy preclude perfect ongoing repair?

Yes, but we don't actually need "perfect". Also: you can counter a lot of entropy from the energy supply of those engines.

Counter-but: we aren't even close to good enough for what we do need.