Damaged interstellar relay towed by a worker bee
An interstellar relay was a type of unmanned communication relay station operated by Starfleet Communications in the mid-23rd century.
In 2256, the USS Shenzhou was dispatched to repair an interstellar relay located in a binary star system at the edge of Federation space. It was eventually found that the Klingons had damaged the relay as a trap, knowing that Starfleet would send a vessel given their exemplary reputation for tech hygiene. (DIS: "The Vulcan Hello")
There were interstellar relays orbiting Earth. (DIS: "Will You Take My Hand?")
StarTrek.com identifies this technology as an "interstellar positioning relay" and states its purpose to be monitoring the remote boundaries of Federation space. [1](X)