Gamma Ray Spectrometer - sswelm/KSPInterstellar GitHub Wiki

The Gamma Ray Spectrometer (or GRS) is an instrument that measures the intensity of Gamma Ray emission across a range of photon energies. It can be used to map the concentration of radioactive, gamma emitting elements, such as Uranium and Thorium directly from orbit.

The Gamma Ray Spectrometer will tell you the concentration of Uranium and Thorium beneath your vessel at all times, resource "hotspots" can also be shown. Thorium is marked in purple and Uranium in yellow. These markers are likewise visible on the map view.