Space scaner detect incoming rocket bug

I think that is the way it's supposed to be? I assumed it was working in the way that if the rocket is approaching or is at base, the signal is active. When on route, signal is false.
But what do I know...

I think this is a bug. Doesn't make sense for the scanner to signal when there's a rocket in the base. That's when I want doors closed. Rocket returning... open doors... rocket lands... close doors. Surely.