this will work great with Space Exploration mod. other surfaces should be untouched;

i tested the following:

local function on_chunk_generated(event)
    local surface = event.surface
    if (surface.name == 'nauvis')
    then
            local lt = event.area.left_top
            local rb = event.area.right_bottom

            local w = rb.x - lt.x   
            local h = rb.y - lt.y
        --    print("Chunk generated: ", lt.x, lt.y, w, h)

            local tiles = {} 
            for y = lt.y-1, rb.y do
                for x = lt.x-1, rb.x do
                    table.insert(tiles, {name=get_world_tile_name(x + spawn.x, y + spawn.y), position={x,y}})
                end
            end
            surface.set_tiles(tiles)
    end
end

I put that change in place. Let me know if you need more.
Also, at first, I didn't realize this was for Earth, not Cities. I was confused as heck. :p

thanks, perfect.