Spy Satellite's Mysterious On-Orbit Fade and a 1981 Spent Booster
According to Dr. Marco Langbroek (sattrackcam.blogspot.com) the satellite performs "what is known to observers as a disappearance trick". The U.S.'s Lacrosse 5 satellite has a tendency to suddenly lose brightness. Russian space junk is also observed.
Credit: Dr. Marco Langbroek (sattrackcam.blogspot.com)