The SuperCam Instrument onboard Perseverance: Overview of the ongoing efforts

Perseverance landed in Jezero crater on February 18^th, 2021. Perseverance is equipped by seven scientific instruments, including the SuperCam suite. SuperCam combines several remote-sensing techniques in order to study both the Martian surface and its atmosphere: 1. the LIBS (Laser-Induced Breakdown Spectroscopy) technique gives access to the chemical composition of the targets (up to 15m); 2. The Raman spectroscopy enables the identification of major mineral phases; 3. The VISIR spectroscopy gives access to the mineralogy, via the reflection of sunlight to access the frequency of molecule bond vibrations of the targets; 4. The Remote Micro Imager (RMI) uses a CMOS camera of 2048x2048 pixels, with an angular size of 10 microradians and a resolution of 50 microradians; 5. The microphone records air pressure fluctuations from 20 Hz to 12.5 or 50 KHz, at sampling rates of 25 or 100 KHz, respectively.

SuperCam performs remote observations around the rover allowing a large number of acquisitions. When analyzing a target, several point analyses are performed when doing LIBS, Raman and/or VISIR, in order to assess its homogeneity and to improve the overall precision. Typically, ten points per target are performed. Moreover, the atmospheric studies require recurrent observations to investigate potential seasonal effects or atmospheric processes.

Up to sol 1100, SuperCam has analyzed a total of 992 geological targets. The laser has primarily been used to collect LIBS observations: 203 000 laser shots were used for the LIBS; whereas 148 000 were used for Raman, and 14 000 for the fluorescence. Raman analyses are more efficient when crystals in the target sample are large and relatively pure, which has been seen infrequently in Jezero crater. A total of 855 activities on mars targets use either the VIS or the IRS technique, for the first time in-situ. This represents a total of 8358 IRS data points for mineralogical investigations. Concerning atmospheric studies, 95 passive sky observations have been performed. The RMI is used to record context images for each analyzed target together with some long-distance investigations. A total of 4270 RMI have been acquired so far. Finally, the microphone is systematically combined with the LIBS activities to gain insight into the target’s physical properties. In addition, it has been used for 498 standalone microphone activities for atmospheric study, representing 22 hours of recording. The SuperCam data can be found on the Planetary Data System.

SuperCam observations have led to more than fifty publications since 2021. This literature addresses the main objectives of the mission: the context of the landing site, the igneous history of the crater floor, investigation of the alteration processes, and the actual environment.

After the crater floor, igneous minerals are encountered along the traverse in the delta in igneous boulders, and also in the delta bedrocks. Comparison of these igneous minerals from the delta and margin unit with those encountered in the crater floor and in Mars meteorites could help constrain their origin. Supercam investigates the composition of the carbonates found in the margin unit by comparing them to the primary minerals composition in order to better constrain their formation processes. Some light-toned float rocks have been encountered since the landing. Their mineralogical composition is modeled using VISIR data but also using LIBS. They also show an elevated Ni content, which could constrain their formation process. Some studies of terrestrial analogs are in progress. SuperCam is also used to investigate specific formations, such as coating and concretions. Comparison of IRS data acquired in situ by SuperCam with orbital observations from the same unit, with different instruments and length scales are ongoing. Multi-instrument studies are also performed on abraded patches to better understand the origin of the carbonates in these samples. VISIR data from SuperCam and MastCam-Z on the abraded patches and drill fines are also associated to document spectral features related to primary and secondary minerals. The first in situ sequence stratigraphic analysis on Mars has been realized on the Kodiak butte. The images acquired in the delta illuminate the fluvial and deltaic stratigraphy throughout the delta to better constrain the fluvial inputs in the crater, and therefore provide insights into the history of Jezero lake. The chemostratigraphy and mineralogy of the western fan revealed a complex aqueous history and alteration conditions in the delta front. The preservation or organic materials is also investigated via Raman data on the organic calibration target onboard the rover.

Since landing, the SuperCam microphone has led to several discoveries, with a review of the acoustic results presented at MarsX conference. One of the latest results describes the high frequency turbulence on Mars. Atmospheric observations have also contributed to the discovery of a Martian aurora from the SuperCam and MastCam-Z instruments. This is the first time such phenomena are observed in situ. Simulation efforts are underway, including a model simulating the propagation of the sound in the lower part of the atmosphere.

Several laboratory investigations are ongoing in support of Mars observations. Some of these studies include specific elemental calibrations, such as P or F. Other studies aim at improving the sensibility of SuperCam to detect serpentine. Some laboratory data explore the Raman signal on chocked carbonates, as observed in Mars meteorites. Some laboratory simulation experiments aim at understanding the formation pathways of the Na perchlorates observed with SuperCam, and others aim at constraining the redox and past aqueous environment during the carbonate formations. A spectral unmixing method is developped to identify some minor and trace elemental lines in LIBS data. A broader database of LIBS spectra is being assembled in order to better quantify LIBS data, which is ongoing. The LIBS plasma dynamics is also investigated to verify the quality of our data. Several modeling efforts are developed for the VISIR data to better identify the mineralogical assemblages present in the targets.