The patient was an unshielded source detected at a few feet. A nuclear weapon in Earth orbit will be shielded by its casing and be hundreds of miles away. The intensity of any radioactive decay signal diminishes as the square of the distance. Norad might be able to estimate a satellite’s density, but that can be spoofed also.
I was referring to a possible suitcase weapon( ground based) that was smuggled into the country.I would believe we also have some kind of “stealth” satellite system up there that checks out orbital payloads.
Really would like to know the missions purpose of the new “spy” spacecraft we have been putting up there.