Just a little history here. During the Vietnam conflict, private United States UFO investigative organizations received reports from their own members who happened to be in the military, stationed in Southeast Asia. APRO's Coral Lorenzen confirmed to me many years ago that APRO members stationed in that part of the world stayed on top of UFO incidents, and indeed various newsletters and journals occasionally reported on S.E. Asian UFO activity. For the most part, news services either remained blissfully uninformed about these incidents, or simply didn't care. But sometimes. . .
This one certainly wasn't among the best reports, but I did find a curious and widely reported September, 1972 news account from Agence France-Presse about an object observed over Hanoi, the capital of North Vietnam. According to a reporter with binoculars, a bright spherical "luminous orange" object appeared high over the city in a clear blue sky and seemed to remain in one position. The thing's mere presence caused Hanoi officials to sound air raid sirens, and barely as soon as warnings ceased three surface-to-air missiles were launched toward the object.
The missiles apparently failed to locate their extremely high target, and nearly an hour and a half later the object was still visible, though not as bright.
I have no further information (nor specific time of day) about this incident (more of an unidentified aerial object encounter than a flying one, so it would properly be called a UAO and not a UFO), and of course our first thought would be that Hanoi officials observed a bright planet, though the color noted suggests otherwise. Something about this affair made it newsworthy, and because no other media reports surfaced with an explanation, and because astronomers apparently did not come forward with a solution, we might assume that this case baffled one and all.