A core sample of Archer's Comet
A core sample was a cylindrical sample taken from below the surface of the ground in order to determine the composition of the underlying materials.
In 2151, Lieutenant Malcolm Reed and Ensign Travis Mayweather were the drilling team sent to the surface of Archer's Comet to extract a core sample of the comet, rich of eisillium. They had to place charges and create an explosion to get closer to the layer and were able to retrieve a core sample by using the drilling rig inside the crater. (ENT: "Breaking the Ice")