The Roswell Incident was declassified as well. It was a weather balloon with a microphone attachment that was meant to listen to a certain layer of the atmosphere where nukes are loudest. I don't have the link as I'm on mobile.
I don't think the government would deny any extraterrestrial claims by the news during the cold war because it would scare the commies shitless if they thought the United States had alien technology.
The US government has been caught spreading alien conspiracy theories. They were the ones supplying Paul Bennewitz with his bogus info to muddy the waters on the stealth craft they were working on at the time.
If I remember the story correctly the balloon was, as you said, to detect nuke detonations. When it crashed the government lied because they didn't want anyone to know what they were up to.
That method of detection wasn't very effective anyway, we figured out much more reliable means of detecting nuclear explosions right on the ground using resonance, but it was pretty obvious the government was lying, so of course peoples imaginations went wild with conspiracies and the ufo thing was born.
It was (and still is) a great thing for the US government, it deflects from what's really going on and keeps the idiots busy chasing bullshit, and the enemies guessing as to what kind of tech they may really have. Toss them a bone once in awhile to keep the frenzy going and you have a reliable means of obfuscation for little to no effort.
Roswell was actually multiple incidents remembered incorrectly iirc
https://open.spotify.com/episode/7droUsVVRsNC3hCXQvd5ph?si=qRPRLKaaQWywq95fubt63Q
Good pod on the topic
