Hi 4space,
That's a very good question. I have a missing sector in front of my door. From my experience I can tell that a missing sector still has its stars. In case of good stars you cannot fully tap into them inside the house but you can still activate them on the outside (if you have a garden or yard there). In case of negative stars, the stars will also still be there and they are not weakened because part of the area is missing.
I hope this helps
Astrid
