A team of researchers led by Prof. Du Aimin from the Institute of Geology and Geophysics of the Chinese Academy of Sciences (IGGCAS) has made a significant discovery during the initial 1-kilometer journey of the Zhurong rover on Mars. Their findings, published in the journal Nature Astronomy on June 19, reveal the presence of extremely feeble magnetic fields, indicating a lack of detectable magnetization anomalies beneath Zhurong’s landing site.
To conduct the first-ever magnetic field survey on the Martian surface within the Utopia Basin, the researchers utilized two fluxgate magnetometers installed on the Zhurong rover. “Surprisingly, we observed remarkably weak magnetic field intensity within the Utopia Basin,” stated Prof. Du Aimin, who serves as both the first author and corresponding author of the study.
Comparing their results to measurements obtained by NASA’s Mars lander InSight, which touched down approximately 2,000 kilometers southeast of Zhurong, the researchers noted a contrasting outcome. InSight’s measurements unveiled a crustal magnetic field at its landing site that was significantly stronger than what orbital measurements had indicated. Conversely, the average intensity of magnetic fields measured by Zhurong was found to be an order of magnitude weaker than what was inferred from orbit.
Precisely measuring planetary surface magnetic fields poses a considerable challenge in the field of planetary exploration. The inclusion of magnetometers on the Zhurong rover marked a pioneering step forward in this regard. The researchers employed a process of along-track calibration, employing rotations of the rover and its mast to differentiate between the Martian magnetic field and any interference caused by the rover itself. As a result, the accuracy of in-situ magnetic measurements on the Martian surface has now reached the nanotesla range.
The remarkably feeble magnetic fields detected by Zhurong suggest two possible explanations. Either the crust beneath the Utopia Basin has remained without magnetization since its formation approximately 4 billion years ago, or it experienced demagnetization due to a significant impact event during the early Hesperian period. This newfound understanding of the timeline of the Martian dynamo contributes valuable insights into the interconnected history of Mars’ magnetic field, climate, and interior processes during its early stages.
Source: Chinese Academy of Sciences