How do the laser pods work?

I'm not sure to understand how the laser pods work, especially their culture/farming system. It looks like you can only have one laser pod per defense tree you own at a time: once the laser pod has been produced, the defense tree it came from won't be able to grow a new seed into a new laser pod until the first one you produced get destroyed.

Also: how are the final laser pod's specs (energy/fight/speed) determined? Is it some sort of average between 1/ the asteroid where the seed comes from and 2/ the asteroid where the defense tree host is situated?