Factorio Forums

Steps: Build something on a space tile, say some underground pipes. Copy them.
Expected: Tiles don't get copied (same as when copying on land), or tiles get listed in the item counts.
Actual: Tiles get copied.
The same thing happens when copying belts:
And buildings:
Copying the space platform tiles does make sense even though it's not consistent with the behaviour of other tiles because you can't build without them, nor can you run underground belts / pipes under a gap. But it should definitely show the number of space platform tiles being copied.

I think it's not actually copying the tiles, but instead ghost building them because they are needed to support the actually copied entities.

For example, you get the same behaviour if you copy stuff from land and try and paste it on water (with shift held down). In which case it will add landfill for you.

It's definitely copying the tiles. If you copy a building but don't catch the full building in the copy rectangle then it goes red when you try to paste it in space, with the error that you can't build in empty space.
But if you copy the entire building it includes the tiles underneath it