[refulgentis]

Ehhh, I guess, maybe to a newcomer who really was hell bent on understanding “exploded in the region” as “exploded on the ground”

Due to ex. gravity, whether it’s at altitude or not is a bit of a nit

[adastra22]

At over 100km it was in space. Three nukes were exploded in space, probably at orbital velocity too. The fact that this was over Antarctica was almost inconsequential.

[wkat4242]

Why at orbital velocity? It's much more efficient to not reach orbital velocity if you just want to explode something at 100km. And an explosion is a momentary thing so there's no need to be in orbit.

[mixmastamyk]

Unlikely that it launched from Antarctica, meaning velocity.

[justrealist]

Read the OP link... they were all launched from US navy vessels.