While exploring, a player may encounter Covert or Besieged Research Facilities, which are commonly known as "Ghost Sites". These differ from other exploration sites in rather dangerous ways, as their containers will eventually self destruct violently after a random, but usually tight timer, often requiring a compromise to be made between leaving some loot behind or risking to lose the ship.
More information on the Covert and Besieged Research Facility sites can be found in the following dev blogs: