The Spectrometers on NASA’s Perseverance

Currently, one of the most popular and talked-about scientific missions is the Mars 2020 mission. This mission, which was designed to collect samples from the Martian surface and investigate the planet for signs of ancient microbial life, saw the launch of the National Aeronautics and Space Administration (NASA)’s Perseverance rover (1). As of April 2025, the rover has uncovered evidence of past water activity, including sedimentary and igneous rocks altered by water, and has been exploring the crater's rim to study rocks ejected during the crater's formation 3.9 billion years ago (1).

The Perseverance rover is equipped with many cameras and different instruments to conduct scientific experiments on Mars, including several spectrometers. The first spectrometer, known as SHERLOC, is mounted on the rover’s robotic arm (1,2). Short for Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals, SHERLOC’s main purpose is to conduct fine-scale detection of organic molecules, minerals, and biosignatures (1,2). To look for signs of life, SHERLOC is assisted by a color camera called WATSON, which takes images of surface textures and rock grains (1,2). By analyzing the chemical makeup of Martian rocks and soil, SHERLOC helps scientists select the most promising samples for potential return to Earth (2). Its investigations are crucial in understanding Mars’ geologic history and assessing its past habitability.

Mars Rover Exploration Red Planet Landscape Futuristic Spacecraft Scientific Mission. Generated by AI. | Image Credit: © Narongsag - stock.adobe.com

The second spectrometer is called the Planetary Instrument for X-ray Lithochemistry, or PIXL. Mounted on the turret at the end of the rover’s robotic arm, PIXL uses a powerful X-ray fluorescence (XRF) spectrometer to determine the abundance of chemical elements at a small scale (2). PIXL also includes a micro-context camera to capture detailed images of rock textures and structures (2). By precisely mapping the distribution of elements, PIXL helps scientists interpret the geologic processes that formed Martian rocks and assess whether the environment may have once supported microbial life. Its high-resolution capability allows for the detection of subtle chemical variations that can indicate ancient biosignatures. PIXL’s data contributes to the selection of rock samples for caching and future return to Earth, making it an essential component in NASA’s search for signs of past life on Mars.

The third spectrometer is called the Mars Environmental Dynamics Analyzer (MEDA). MEDA monitors the Martian atmosphere and the weather by measuring wind speed and direction, air and ground temperatures, atmospheric pressure, relative humidity, and radiation across ultraviolet, visible, and infrared (IR) wavelengths (1,2). It also assesses dust properties, including particle size and concentration, which are crucial for understanding Martian weather and climate (2). MEDA is designed to provide continuous reports on the Martian weather from the Jezero Crater, which is where Perseverance has conducted its research (2). The information that is collected from MEDA helps scientists learn more about the Martian weather and environment, which is important in designing equipment and habitats that can withstand the planet's harsh environmental conditions.

The fourth instrument was the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), which was designed to produce oxygen from Mars’ carbon dioxide-rich atmosphere. This instrument is one of the first steps in NASA’s preparation for human exploration on Mars (2). Utilizing solid oxide electrolysis, MOXIE heated Martian air to approximately 800°C, separating CO₂ molecules into oxygen and carbon monoxide (2,3). Between April 2021 and August 2023, the toaster-sized device generated 122 grams of oxygen, with peak outputs reaching 12 grams per hour at 98% purity (3). MOXIE’s success paves the way for future missions to scale up this technology, potentially producing the substantial oxygen quantities needed for rocket propellant and life support.

And finally, the Radar Imager for Mars’ Subsurface Experiment (RIMFAX) is designed to allow scientists to see geological features underneath the Martian surface using radar. It reveals subsurface rock layers, helping scientists study Mars’ geologic and climate history (4). The findings from RIMFAX have suggested, for example, that Mars had volcanic and sedimentary formations, which might indicate past water presence on the planet (4).

References

1. NASA, Mars 2020: Perseverance Rover Homepage. NASA.gov. Available at: https://science.nasa.gov/mission/mars-2020-perseverance/ (accessed 2025-04-18).
2. NASA, Mars 2020: Perseverance Rover. NASA.gov. Available at: https://science.nasa.gov/mission/mars-2020-perseverance/science-instruments/#spectrometer (accessed 2025-04-18).
3. Jet Propulsion Laboratory, NASA’s Oxygen-Generating Experiment MOXIE Completes Mars Mission. NASA.gov. Available at: https://www.jpl.nasa.gov/news/nasas-oxygen-generating-experiment-moxie-completes-mars-mission/ (accessed 2025-04-18).
4. NASA, Searching for Buried Treasure on Mars With RIMFAX. NASA.gov. Available at: https://science.nasa.gov/blog/searching-for-buried-treasure-on-mars-with-rimfax/ (accessed 2025-04-18).