> up to 18km/s

Vs

> 0.1c

Off by quite a bit

Where are you getting either of these figures?

The up to 18km/s is from the linked shield.

Up to 0.1c is from the interstellar spaceship competition "cruise" speeds (also used 0.01c) as presented in their deck.

They're a few orders of magnitude difference.

Also, there's plenty of resources around on interstellar travel that shows interstellar dust/debris is going to be a huge problem.

For example Atomic Rockets, which has a bunch of good reference materials (albeit poorly organized), or the Astronomy Cafe

https://sten.astronomycafe.net/at-what-speed-does-the-inters...

Whipple shields are consumed by impacts.

> Whipple shields are consumed by impacts

Everything is consumed on such a voyage. If we can send a generation ship at 0.01c, we can send replacement parts quicker and probes ahead to verify our estimates even faster.

Are you just casually handwaving away sending a dockable resupply ship at 0.01c to somewhere in interstellar space, then doing some kind of rendesvous with it at 0.01c with a spaceship measured kilometers in length?

There's no free lunch. Every gram of mass that you want to get to interstellar space requires exactly as much fuel to get there as you'd have to add to the original spacecraft to just carry it.

(thought experiment - have them fly side by side, then connect them by string, then shorten the string until they touch, then weld them together - the fuel required doesn't change at any point).

And a shield + a resupply ship has a lot more grams than just adding the shield to the original thing.