An ultraviolet-light instrument on the robotic arm of NASA’s Mars 2020 rover will use two types of ultraviolet-light spectroscopy, plus a versatile camera, to help meet the mission’s ambitious goals, including a search for signs of past life on Mars and selection of rock samples for possible return to Earth. It is called SHERLOC, for Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals.
“This instrument uses two distinct detection strategies,” said its principal investigator, Luther Beegle of NASA’s Jet Propulsion Laboratory in Pasadena, California. “It can detect an important class of carbon molecules with high sensitivity, and it also identifies minerals that provide information about ancient aqueous environments.”
SHERLOC will shine a tiny dot of ultraviolet laser light at a target. This causes two different spectral phenomena to occur, which the instrument captures for analysis. The first is a distinctive fluorescence, or glow, from molecules that contain rings of carbon atoms. Such molecules may be clues to whether evidence of past life has been preserved. The second is an effect called Raman scattering, which can identify certain minerals, including ones formed from evaporation of salty water, and organic compounds. This dual use enables powerful analysis of many different compounds on the identical spot. Via SHERLOC to micro-map Mars minerals and carbon rings.