All ships and planets have the ability to detect objects within a given radius, depending on settings which can be altered at game setup. Each can see other objects of the chosen type that exist within that radius. The default detection range for ships is 300 Light-Years; the default detection range for planets is 10,000 Light-Years (or rather larger than the Echo Cluster). Minefields can't be detected except by ships on the Mine Sweep or (in a limited form) Lay Mines missions. Most other navigational hazards are detectable at the planetary range.