I'll bet that back in the 60s more than a few of these were reported as UFOs.
I only ever saw one fly. June 1968 in Colorado Springs.
The thing was awesome. Just plain awesome.
The stillborn YF-12A variant was even meaner looking.
I always thought the sensors on the leading edge just off of the nose, always looked sinister to me.
To think that those things were designed with sliderules and built without CNC...can you imagine working on that project?
It had to be a blast.