[Spktyr]

Not quite true. France continued atmospheric testing all the way through to 1974 and China didn’t stop until 1980. The laggers’ tests did include microprocessor study samples.

[cynwoody]

But nobody in modern times has lofted a nuke well into the ionosphere and studied the consequences of its detonation.

The concern of the thread is, what if the Norks (or the Iranians) do it for real over the present-day USA?

The laggers’ tests did include microprocessor study samples.

And the results were? Do tell!

Starfish Prime was not the first high-altitude test by the US. There were others, but the results were inconclusive. There was one test, on 31 July 1958, 47 miles above Johnston Island. It was visible from Hawaii for half an hour. HF communication across the Pacific was knocked out. Johnston Island was unable to contact the mainland for eight hours.