Naval Oceanic Surveillance Satellite
On the evening (August 10, 1996) before the peak of the popular Perseid Meteor shower, many amateur astronomers noticed an unusual array of three satellites traveling in formation across the Eastern half of the US. I was fortunate to observe these satellites from a dark sky (mag 6.5) site in Montana. The three satellites were about the same brightness and angular size as the constellation Delphinus, through which they were traveling. This was a stunning, if not a puzzling sighting! Previously, I was unaware of satellites which traveled in formation. From my understanding of orbital mechanics, satellite formations are unstable, the satellites will disperse in a few orbits.
Astronomy Magazine (November, 1996) reported and identified the August 10, 1996 sightings as "Whitecloud", a secret naval oceanographic surveillance system. Recently, I have found The Satellite Encyclopedia a website which describes in more detail the experiments of "Whitecloud". Look up the NOSS listing for information about "Whitecloud" and "Triplet". In fact, "Whitecloud" experiments were begun in the 1970s and discontinued several years ago. There is a new program to replace "Whitecloud", now named "Triplet". I do not know the original source of this information, but it is intriguing.
I am very interested in hearing about your observation and learning more about these satellites - public information only!