Perseverance rover SHERLOC's (scanning habitable environments with raman and luminescence for organics and chemicals) calibration target. NASA's Mars 2020 mission will study the geology of Mars and search for any signs of life. SHERLOC is a UV Raman laser spectrometer that will look at the minerals and organic compounds on Mars. The calibration target contains known materials (top row) to fine-tune the instruments. The bottom row of the calibration target contains materials from a spacesuit to test how they change in the Martian atmosphere. The calibration target also has a glass disk (circle, bottom left) with an inscription for the fictional detective Sherlock Holmes and a trackable code accessible to the public.