INDICATORS ON UNDERWATER NUCLEAR TEST 'UMBRELLA' (1958) YOU SHOULD KNOW

With test moratoriums to the horizon, American weapons labs rushed out many new patterns. A hard deadline for testing was established at midnight (0000 hrs), 31 Oct 1958, as negotiations ended up established to get started on that day, along with the timetable demonstrates it, with 29 tests executed in October, 4 of these on the last working day. 1