The Perseverance rover landed in Jezero crater, Mars in February 2021. We used the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument to perform deep ultraviolet Raman and fluorescence spectroscopy of three rocks within the crater. We identify evidence for two distinct ancient aqueous environments at different times. Reactions with liquid water formed carbonates in an olivine-rich igneous rock. A sulfate-perchlorate mixture is present in the rocks, probably formed by later modifications of the rocks by brine. Fluorescence signatures consistent with aromatic organic compounds occur throughout these rocks, preserved in minerals related to both aqueous environments.

The goals of NASA's Mars 2020 mission include searching for evidence of ancient life on Mars, studying the geology of Jezero crater, understanding Mars' current and past climate, and preparing for human exploration of Mars. During the mission's first science campaign, the Perseverance rover's SHERLOC deep UV Raman and fluorescence instrument collected microscale, two‐dimensional Raman and fluorescence images on 10 natural (unabraded) and abraded targets on two different Jezero crater floor units: Séítah and Máaz. We report SHERLOC Raman measurements collected during the Crater Floor Campaign and discuss their implications regarding the origin and history of Séítah and Máaz. The data support the conclusion that Séítah and Máaz are mineralogically distinct igneous units with complex aqueous alteration histories and suggest that the Jezero crater floor once hosted an environment capable of supporting microbial life and preserving evidence of that life, if it existed.

The presence and distribution of preserved organic matter on the surface of Mars can provide key information about the Martian carbon cycle and the potential of the planet to host life throughout its history. Several types of organic molecules have been previously detected in Martian meteorites1 and at Gale crater, Mars2–4. Evaluating the diversity and detectability of organic matter elsewhere on Mars is important for understanding the extent and diversity of Martian surface processes and the potential availability of carbon sources1,5,6. Here we report the detection of Raman and fluorescence spectra consistent with several species of aromatic organic molecules in the Máaz and Séítah formations within the Crater Floor sequences of Jezero crater, Mars. We report specific fluorescence-mineral associations consistent with many classes of organic molecules occurring in different spatial patterns within these compositionally distinct formations, potentially indicating different fates of carbon across environments. Our findings suggest there may be a diversity of aromatic molecules prevalent on the Martian surface, and these materials persist despite exposure to surface conditions. These potential organic molecules are largely found within minerals linked to aqueous processes, indicating that these processes may have had a key role in organic synthesis, transport or preservation.

We describe the wavelength calibration of the spectrometer for the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard NASA’s Perseverance Rover. SHERLOC utilizes deep-UV Raman and fluorescence (DUV R/F) spectroscopy to enable analysis of samples from the martian surface. SHERLOC employs a 248.6 nm deep UV laser to generate Raman scattered photons and native fluorescence emission photons from near-surface material to detect and classify chemical and mineralogical compositions. The collected photons are focused on a charge-coupled device (CCD) and the data are returned to Earth for analysis. The compact DUV R/F spectrometer has a spectral range from 249.9 nm to 353.6 nm (~200 cm-1 to 12000 cm^−1) (with a spectral resolution of 0.296 nm (∼40 cm^−1)). The compact spectrometer uses a custom design to project a high-resolution Raman spectrum and a low-resolution fluorescence spectrum on a single CCD. The natural spectral separation enabled by deep UV excitation enables wavelength separation of the Raman/fluorescence spectra. The SHERLOC spectrometer was designed to optimize the resolution of the Raman spectral region and the wavelength range of the fluorescence region. The resulting illumination on the CCD is curved, requiring a segmented, non-linear wavelength calibration in order to understand the mineralogy and chemistry of martian materials.

We describe a new compact diode-pumped solid-state frequency quadrupled quasi-three-level neodymium-doped gadolinium vanadate (Nd:GdVO 4) laser that generates $50 mW of 228-nm quasi-continuous wave light as ns pulses at a tunable kilohertz repetition rate. We developed two generations of this laser. The first generation has a high duty cycle and a tunable repetition rate. The second generation is optimized for maximum output power. We utilize these new lasers to measure ultraviolet resonance Raman (UVRR) spectra of many important chromophores that absorb in deep ultraviolet (UV). We demonstrate the utility of this excitation by measuring the 228-nm absolute differential Raman cross sections of explosives, peptides, aromatic amino acids, and DNA/RNA nucleotides. Deep UV excitation at 228 nm occurs within the π ! π* electronic transitions of these molecules. The 228-nm resonance excitation enhances the Raman intensities of vibrations of NO x groups, peptide bonds, aromatic amino acid side chains, and DNA/RNA nucleotides. The measured 228-nm UVRR cross sections of these molecules are 10 3-10 4 fold greater than those excited in the visible spectral region. These new lasers should be of great interest for UVRR spectroscopy and for other applications that benefit from compact, high average power deep UV laser light sources with low peak powers.