Mysterious Russian satellites are now breaking apart in low-Earth orbit - Ars Technica

The mission carried three small military communications satellites, but observers noted that the mission appeared to eject a fourth object into orbit.

In May 2014 another Rokot booster carried three communications satellites into orbit as well as a fourth object, which was designated Cosmos 2499.

Finally, this happened a third time in April 2015, with a third mystery satellite known as Cosmos 2504.

However, the Object E satellites are now causing a more significant concern in low-Earth orbit.

There are not that many sizable chunks of debris from the small satellites; however, this debris will be long-lived, as it starts out at such a high altitude above Earth's atmosphere.