You can’t build chests in space, so there’s very limited buffering or surplus options.

I think the biggest change with space is that it appears that the asteroids are an infinite resource.

Yep, but if you run out of storage space then The Factorio Way™ has always been to use some kind of destruction method - from handgunning a wooden box to using a mod to vaporize it into the ether.

The factory may need those resources to grow at some point. Best to stash em away just in case.