Spectroscopy on Mars: How NASA’s SHERLOC is Redefining Planetary Exploration

By Ibtisam AbbasiReviewed by Louis CastelOct 13 2025

Spectroscopy plays a vital role in planetary exploration, offering a powerful tool for analyzing the molecular structure of matter. In astrobiological missions, it enables researchers to study mineral surfaces in detail and investigate potential signs of extraterrestrial life. By capturing and interpreting spectral data, scientists can efficiently characterize planetary materials and environments, making spectroscopy an essential technique in the search for life beyond Earth.¹

Image Credit: Shutterstock.com

The Perseverance Mars rover is an astrobiology-focused mission designed to search for signs of microbial life on Mars, that incorporates a seven-instrument suite for performing high-quality imaging and spectroscopic analysis. Central to this effort is SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals), a Raman spectroscopy instrument that enables fine-scale metrological analysis and the detection of organic compounds. By analyzing the mineralogy and chemistry of Martian rocks and soil, SHERLOC helps scientists assess the planet’s past habitability and potential biosignatures.

What is SHERLOC and How Does it work?

The SHERLOC instrument is located at the end of the robotic arm of the Perseverance Mars rover. This advanced instrument is equipped with an auto-focusing camera that captures black-and-white images and supports WATSON (Wide Angle Topographic Sensor for Operations and eNgineering), SHERLOC’s companion system designed for taking high-resolution color images and analyzing rock textures. SHERLOC also features a high-powered laser that targets the precise center of geological samples on the Martian surface. This laser is essential for conducting Raman spectroscopic analysis, enabling the detection of minerals in microscopic rock features with pinpoint accuracy.²

Download the PDF of the article

Spectroscopy Modes for Detection of Life

SHERLOC analyzes the availability of key organic elements, including organic macromolecules, steranes, and energy sources on the Martian surface, rocks, and outcrops. It includes micro and macro-mapping modes, allowing for the analysis of the morphology and mineralogy of bio-signatures using Deep UV (DUV) native fluorescence and resonance Raman spectrometry techniques.

Using deep UV laser-induced fluorescence, SHERLOC employs a laser to excite atoms and molecules within Martian geological samples. As these excited particles return to their ground state, they emit photons through the fluorescence process. This emission provides critical data, enabling the detection of biological microorganisms, organic compounds, and other materials present in the soil and minerals. Thanks to its high spatial resolution, SHERLOC can analyze these features with exceptional detail, making it a powerful tool in the search for past or present life on Mars.³

Furthermore, SHERLOC’s narrow-linewidth (<3 GHz) DUV laser (248.6 nm) also makes it possible to perform fluorescence-free resonance and pre-resonance Raman spectroscopic analysis, which helps further classify aromatic and aliphatic organics as well as minerals.⁴ These attributes make SHERLOC a crucial instrument for astro-biological Mars exploration missions.

Key Discoveries So Far

In February 2021, NASA’s Perseverance rover explored Jezero crater. During the first campaign, the SHERLOC instrument collected microscale, 2-D images displaying mineral and organic molecule detections on 10 different natural and abraded targets.

During the Crater Floor Campaign, SHERLOC analyzed 10 distinct targets; three from the Séítah region, all of which had abraded surfaces, and seven from the Máaz region, consisting of three natural surfaces and four abraded ones. The mineral identifications across these targets included a range of compositions, such as undefined silicate, olivine, phosphate, pyroxene, and sulfate. These findings help build a clearer picture of the geological diversity and past environmental conditions on Mars.

In the Séítah region, SHERLOC identified a variety of minerals at the Dourbes abrasion site, with carbonate and pyroxene emerging as the most prominent. Using laser-induced fluorescence spectroscopy, the instrument delivered spatially resolved data on elemental composition, revealing the presence of silicon, magnesium, and aluminum. These results offer valuable insights into the mineralogical makeup and potential habitability of ancient Martian environments.⁵

In its first 400 days on Mars, the Perseverance rover detected a wide range of organic molecules, including polycyclic aromatic hydrocarbons (PAHs), compounds often considered potential building blocks of life. SHERLOC plays a key role in this process, working in tandem with the WATSON camera to capture detailed images of rock textures and mineral structures. By integrating these images with spectral data, SHERLOC creates spatial maps that show the distribution of minerals and organic compounds across rock surfaces, helping scientists understand the chemical and environmental history of the region.⁶

Experts analyzed samples from different craters, like the Jezero crater, and published the findings in the journal Nature. The research paper revealed that the detections by both fluorescence and Raman spectroscopy are consistent with the presence of organic materials. The analysis suggests that the organic molecules may have been deposited through abiotic aqueous processes or formed within the altered volcanic materials on the crater floor. However, confirming their organic origin and precisely identifying these molecules will require returning the samples to Earth for laboratory study.⁷

Future Implications

SHERLOC continues to play a crucial role in collecting targeted samples from Martian rocks and sub-surfaces. In 2023, two key samples were acquired with the help of SHERLOC’s camera system, which was instrumental in identifying core mineral surfaces and capturing detailed imagery to guide successful drilling operations. These efforts are part of the broader Mars Sample Return mission, which, following approval by the U.S. Congress, aims to bring these samples back to Earth by 2030.⁸

Experts continue to refine spectroscopy techniques and instruments to enhance accuracy and efficiency in space and planetary exploration. In a recent breakthrough, researchers from the Netherlands developed a compact, lightweight terahertz spectrometer, measuring just a few centimeters, that has the potential to replace traditional, bulkier spectroscopy equipment. This advancement could significantly reduce payload weight and fuel consumption for future missions. At the core of this innovation is a high-performance metasurface, which enables the spectrometer to outperform many conventional systems despite its smaller size.⁹

Recent innovations underscore the critical role of spectroscopy and optical instruments in planetary exploration. With growing investment in advanced imaging technologies, researchers and space agencies are focused on improving performance while reducing operational costs. Looking ahead, we can expect to see increasingly intelligent and miniaturized spectroscopy systems used not only in the search for life on distant planets, but also in probing large-scale cosmic phenomena like the expansion of the universe.

Read the full story of Perseverance on AZoQuantum

Further Reading

1. Hanke, F. et. al. (2023). Comparative Raman spectroscopy of astrobiology relevant bio-samples and planetary surface analogs under UV–VIS–IR excitation. Journal of Raman Spectroscopy. 1(55). 26-42. Available at: https://doi.org/10.1002/jrs.6603
2. National Aeronautics and Space Administration (NASA). Jet Propulsion Lab, Caltech. (2025). Mars 2020’s SHERLOC Instrument. [Online]. Available at: https://science.nasa.gov/resource/mars-2020s-sherloc-instrument/ [Accessed on: September 27, 2025].
3. Hanson Research Group, Stanford University (2025). Laser-Induced Fluorescence. Imaging and Photophysics. [Online]. Available at: https://hanson.stanford.edu/our-approaches/imaging-and-photophysics/laser-induced-fluorescence. [Accessed on: September 27, 2025].
4. Washington University in St. Louis (2025). SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals). Mars 2020 (Perseverance). Instruments. [Online]. Available at: https://an.rsl.wustl.edu/help/Content/About%20the%20mission/M20/Instruments/M20%20SHERLOC.htm#:~:text=SHERLOC%20will%20ascertain%20if%20there,steranes%2C%20organic%20macromolecules%2C%20etc. [Accessed on: September 28, 2025].
5. Corpolongo, A. et. al. (2023). SHERLOC Raman mineral class detections of the Mars 2020 Crater Floor Campaign. Journal of Geophysical Research: Planets, 128(3), e2022JE007455. Available at: https://doi.org/10.1029/2022JE007455
6. NASA's Jet Propulsion Laboratory, California Institute of Technology. (2025). NASA’s Perseverance Rover Sees Mars in a New Light. MARS. [Online]. Available at: https://www.jpl.nasa.gov/news/nasas-perseverance-rover-sees-mars-in-a-new-light/ [Accessed on: September 28, 2025].
7. Sharma, S. et al. (2023). Diverse organic-mineral associations in Jezero crater, Mars. Nature. 619. 724–732. Available at: https://doi.org/10.1038/s41586-023-06143-z
8. Wogsland, B. et. al. (2023). Science and Science-Enabling Activities of the SHERLOC and WATSON Imaging Systems in Jezero Crater, Mars. Earth and Space Science. 10(11). e2022EA002544. Available at: https://doi.org/10.1029/2022EA002544
9. Communication TNW, Delft University of Technology (2024). Revolutionary terahertz spectrometer: a step forward in space observation. [Online]. Available at: https://www.tudelft.nl/en/2024/tnw/revolutionary-terahertz-spectrometer-a-step-forward-in-space-observation [Accessed on: October 1, 2025].

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.