A new analysis of data collected by NASA’s Spirit rover identified minerals that suggest vast areas of Mars may have been covered by water in the past. The investigation also demonstrates the potential of revisiting information gathered during older space missions with new analytical techniques.
More than two decades after Spirit arrived on the surface of Mars, a new investigation has reinforced the evidence that the red planet may have had water across much of its surface.
The study, led by Paulo de Souza, Vice-Chancellor for Research at Edith Cowan University (ECU) in Australia, reanalyzed data collected by NASA’s rover between 2004 and 2010 and identified traces of minerals whose formation is associated with the presence of water.
The investigation focused on observations conducted at 32 intact soil sites in Gusev Crater, an ancient impact basin that was chosen as Spirit’s landing site because it showed signs of past water activity.
By combining hundreds of measurements taken over more than 2,000 Martian days, the researcher was able to produce the most detailed profile to date of the mineralogical composition of iron present in typical Martian soils.
Among the main results is the identification of crystalline hematite and altered magnetite, minerals that can form when rocks interact with water.
“One of the most important discoveries was finding crystalline hematite in common Martian soil,” says Paulo de Souza.
According to the researcher, the widespread presence of this mineral suggests “not only that water existed, but that significant areas of Mars may have been covered by water.”
Until now, scientists believed hematite was virtually absent from these soils. However, the new analysis indicates that the mineral was already present in the original data, albeit in concentrations too low to be identified by the rover’s individual measurements.
Paulo de Souza explains that the mission’s instruments were limited by operating time, available energy, and the natural wear over the years of exploration.
By integrating all observations into a single data set and applying new analytical methodologies, it was possible to identify information that had remained hidden for more than two decades.
In addition to reinforcing the hypothesis that water played an important role in Mars’ geological evolution, the study also supports the idea that large parts of the planet are covered by a relatively homogeneous layer of dust and soil, formed over millions of years by wind action, extreme temperature variations, and the transport of particles across the Martian surface.
For the researcher, the results also demonstrate the importance of revisiting data obtained from previous space missions.
“This work shows that important discoveries do not always result from collecting new data,” says Paulo de Souza. “Sometimes they arise from looking at existing data with a new perspective and using more advanced analysis techniques.”
The study was published in the scientific journal Interactions, by Springer Nature.
