I worked with an Air Force Vietnam veteran who worked at SAC and handled the side-looking cameras of the Blackbird. He told me some interesting stories.
One of the stories was when he was hanging out around the back of a refueling tanker. From his account, in order to refuel, the tanker had to go into a pretty steep dive at high subsonic Mach, with the SR71 matching the trajectory, in order for the Blackbird to refuel. It was, as he described it, a hair-raising operation. There would be three tankers lined up in intervals, in case one wasn't able to refuel the Blackbird successfully, the Bird would zoom up to meet the next tanker. If by the third tanker it was still unsuccessful, the mission would be aborted.
Other colleagues said that this man was always FOS, but I'm naive enough to take him at his word.
Online research shows nothing of the kind. Maybe he was embellishing a lot. But online research also has no information on the 494L nuclear second-strike system that the US used to use, he described it to me in some detail, as he programmed the thing.