The No-Spawn Zone is a lot like the Build Zone. Like the build zone it has a radius of effect, it needs to be powered by a power frame and it makes a nebula. The biggest difference is the effect, the No-Spawn Zone makes an orange nebula that makes it impossible to teleport in to.
It so happens that every now and again a creature will teleport into your great mothership. All the weapons couldn't stop it, they are aimed from the outside parameter. If only we had the No-Spawn Zone. Now you do, use it!
Simplest way of making the No Spawn Zone work is by power frame. Other means of powering may be used aswell of course.
Note: Orange nebula do not naturally spawn, they can only be created by No-Spawn Zone.