Strangest fact
The photos are real NASA pictures of a real unknown-looking object in orbit, and it does look like a black, angular machine. It is a case where the evidence is genuine and the story attached to it is not.
The Black Knight story is a patchwork of unrelated events, as Space.com and others have traced. Believers point to radio signals Nikola Tesla reported in 1899, to long-delayed radio echoes heard in Norway in 1927, to 1954 newspaper stories about claims that the Air Force had detected two artificial satellites before any were launched, and to a 1960 report of a 'dark object' in orbit that turned out to be part of the American Discoverer 8 spy satellite.
The pictures that made the legend famous came from STS-88 in December 1998, the first shuttle mission to assemble the International Space Station. They show a dark, twisted, wing-like object against the Earth. NASA's astronaut photo catalog lists frame STS088-724-66, taken on December 11, 1998, with the feature tag "SPACE DEBRIS."
During a spacewalk on that mission, astronaut Jerry Ross was installing thermal covers on the new Unity module when one came loose. Commander Robert Cabana told him, Jerry, one of the thermal covers got away from you.
NASA's STS-88 mission summary lists a trunnion pin cover
among items that floated away. The cover was tracked as debris and, according to fact-checkers, re-entered the atmosphere on December 14, 1998.
James Oberg, who worked on the STS-88 trajectory team and knows the astronauts involved, says the photographs show that lost blanket. A flexible blanket with a dark side and a shiny side, tumbling in harsh sunlight, changes shape from frame to frame, which is why the photos look so strange.