The rover discovered some unexplainable variations in the oxygen levels.
Curiosity’s Sample Analysis at Mars (SAM) instrument is used by NASA scientists to monitor the amount of different substances in the martian atmosphere and their seasonal variations. A few days ago, the space agency released the results of their discoveries for the last five years.
Many of the results were not surprising, as the majority of substances had the variations predicted. The surprise came when observing the oxygen level variations, which defied any expectations scientists might have had.
The researchers said that the findings suggest “significant seasonal and inter-annual variability, suggesting an unknown atmospheric or surface process at work.” The oxygen measurements in the Gale crater don’t show the expected stability or patterns based on the knowledge sources and sinks in the atmosphere of the red planet.
Curiosity picked up higher amounts of oxygen than expected during the northern hemisphere’s late spring and summer and less oxygen than expected during the northern hemisphere’s winter. NASA scientists have already come up with various theories that could explain this phenomenon. One of them claims that the rover’s SAM instrument might be broken, but the explanation for it is lacking.
Melissa Trainer, a planetary scientist at NASA, said: “The fact that the oxygen behavior isn’t perfectly repeatable every season makes us think that it’s not an issue that has to do with atmospheric dynamics. It has to be some chemical source and sink that we can’t yet account for.”