![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2025\/04\/1-PIA26554-Curiosity_Surveys_the_Ubajara_Sampling_Site_4-Figure_A.jpg\")
<\/p>\nNASA\u2019s Curiosity rover, which has been driving around the surface of Mars for over 12 years, recently discovered a mineral called siderite on the slopes of Mount Sharp in Gale Crater. Interestingly, siderite might be the mineral that helps planetary scientists finally solve the mystery of where Mars\u2019 carbon dioxide-rich atmosphere went.<\/p>\n
Solving such a mystery could prove vital to understanding the red planet\u2019s past and provide scientists with insight into how the atmosphere of Mars evolved to its current state.<\/p>\n<\/p>\n
Currently, Mars has a thin atmosphere composed of approximately 95% carbon dioxide. Scientists have long theorized that Mars\u2019 atmosphere was once much thicker and rich with carbon dioxide. When coupled with flowing liquid water on the surface, this ancient atmosphere and water should have reacted with surface features to create carbonate materials. However, no missions to Mars have been able to identify such carbonate materials \u2014 until Curiosity\u2019s latest discovery.<\/p>\n
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Curiosity\u2019s image of its tracks leaving the Ubajara site in Gale Crater, where siderite was later discovered. (Credit: NASA\/JPL-Caltech\/MSSS)<\/p>\n
As discussed in a new study led by Benjamin Tutolo of the University of Calgary in Canada, data collected from several of Curiosity\u2019s drill sites in Gale Crater have shown the presence of siderite. Siderite is an iron carbonate mineral that exists within the sulfate-rich rocky layers of Mount Sharp, the 5,500 m tall mountain at the center of the crater that Curiosity is climbing.<\/p>\n
\u201cThe discovery of abundant siderite in Gale Crater represents both a surprising and important breakthrough in our understanding of the geologic and atmospheric evolution of Mars,\u201d Tutolo said.<\/p>\n
Curiosity\u2019s drill is used by planetary scientists to further study the chemical and mineral composition of the red planet. By drilling three to four centimeter holes into the Martian surface, Curiosity collects powdered rock samples and drops them into its Chemistry and Mineralogy (CheMin) instrument.<\/p>\n
Once deposited into CheMin, the instrument uses X-ray diffraction to analyze the dust and soil samples. The results from CheMin\u2019s analysis are then sent back to Earth, where scientists at NASA\u2019s Johnson Space Center Astromaterials Research and Exploration Science (ARES) division further analyze the data.<\/p>\n
NASA mission updates (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n \u201cDrilling through the layered Martian surface is like going through a history book. Just a few centimeters down gives us a good idea of the minerals that formed at or close to the surface around 3.5 billion years ago,\u201d said NASA Ames research scientist Thomas Bristow, who served as a co-author of the paper.<\/p>\n Curiosity drills into rock on the surface of Mars. (Credit: NASA\/JPL-Caltech\/MSSS)<\/p>\n The discovery of siderite within the slopes of Mount Sharp suggests that other, non-carbonate materials may mask carbonate minerals on Mars in infrared satellite analysis. While other sulfate-rich layers on the surface may contain carbonates like siderite, the amount of carbon dioxide stored within them would be much less than the amount needed for a thicker atmosphere to support liquid water. Thus, the rest of the carbon dioxide needed to support the existence of this ancient atmosphere must be hidden in deposits elsewhere on the Martian surface or lost to space over time.<\/p>\n To confirm where the rest of Mars\u2019 surface carbon dioxide is hidden, scientists will need to send more missions to sulfate-rich areas on the Martian surface. Furthermore, continued analysis of these regions using orbital data could prove useful in solving the mystery of Mars\u2019 once-thick atmosphere.<\/p>\n![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2025\/04\/MarsCuriosityRover-Drilling-01-e1745479564440.jpg\")
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