[Ruy Dias de Bivar]

If I remember what I read many years ago, a US satellite picked up a super lightning bolt in a cloud formation off South Africa.

Some then speculated that Israel and South Africa had co-operated to build a nuke bomb and the lightning flash was really a test of the bomb.

[Calvin Locke]

US satellites also look for GRBs as well, a telltale sign of a nuclear explosion.