Strangest fact
The 'objects' look like notched discs, and some seem to go behind a tether that was miles away. If that were true they would have to be enormous.
STS-75, flown by Space Shuttle Columbia in February and March 1996, carried the Tethered Satellite System, an Italian satellite on a thin conducting cable, to study electricity in the upper atmosphere. NASA's mission summary says the tether snapped on flight day three when the satellite was just short of full deployment of about 12.8 miles (20.6 kilometers)
and the satellite sped away. The crew was never in danger.
Cameras kept filming the loose tether as it drifted off. In the footage, the tether appears as a bright line, and many glowing dots and larger round shapes with dark centers seem to move around it, some apparently passing behind it. Promoters of the clip have presented it as showing UFOs approaching the tether.
At the time, astronaut Franklin Chang-Diaz described the objects as a little bit of debris that kind of flies with us,
lit by the Sun, according to a 2014 Houston Chronicle report. Later analysis, summarized in the same report, noted that the camera lens used a mirror design with a hole in the middle, which turns out-of-focus points of light into rings with dark centers. The bright, overexposed particles near the camera look large and can seem to pass behind the far-off tether even though they are in front of it.