Target buoy
A target buoy was a type of unmanned probe designed to be destroyed as a mean of testing weapons capability.

Such a buoy was utilized by the Entharan weapons merchant Kovin while demonstrating the use of an isokinetic cannon, which he was attempting to sell to Captain Janeway of the  in 2374. The cannon was able to successfully destroy a target buoy composed of ten-meter thick solid monotanium, protected by a chromoelectric force field. ()

See also 
 Target drone

Military technology