If you're talking about nuclear weapons, their major effect on satellites (Starfish Prime as the reference point) isn't EMP effects, but ionizing radiation—crea

If you're talking about nuclear weapons, their major effect on satellites (Starfish Prime as the reference point) isn't EMP effects, but ionizing radiation—creating a persistent radiation belt of MeV electrons. (A physical process that took months to disable some satellites). Beyond that I don't know much.