[Space] Panspermia and the Campgaign

[Anthony]

Originally Posted by whswhs

What scale of agriculture or mining?

Earth 250 years ago, as you specified, though even 5,000 years ago you'd be able to detect and at least recognize as odd agricultural patterns in areas such as the Nile. TL0 wouldn't be visible from space, but TL 1+ won't hide at interplanetary distances.