This is a lesser known one originally uncovered by longtime Sydney researcher Bill Chalker that adds to the question...why are UFO encounters so often
near nuclear assets?
Australian RAAF files show in 1973, following a DEFCON 3 nuclear alert sent out by a base at North West Cape, two officers saw a “black sphere”
UFO hovering and soon after, take off with near instantaneous acceleration. The NSA wrote about an incident that year, though all information is
redacted.
One month earlier, a Soviet officer at the Sary Shagan Weapons Testing Range in what is now Kazakstan saw a green, circular UFO that expanded into
concentric circles when observed. Sary Shagan was a major site of USSR atmospheric nuclear testing in the 60s.
Two years later, in late 1975 and early 76, six different USAF bases in the American mainland reported their own encounters, most of whom stated craft
were seen just a few hundred feet above weapons storage areas. A lot of these cases get lost or forgotten, but when put together, it really does feel
like nuclear assets are being surveyed, and when multiple trained observers see instantaneous acceleration and forces that would kill ordinary human
pilots, one has to ask if these are extraterrestrial or inter dimensional in nature, or something (or some clandestine group) on Earth that's been
here and is capable of technology governments don't have.