Spirit captured this panorama on the summit of "Husband Hill" inside Mars' Gusev Crater. Credits: NASA/JPL-Caltech/Cornell
More than 20 years after NASA's Spirit Rover landed on Mars, a researcher from Edith Cowan University (ECU) has uncovered new evidence that suggests water may once have covered large parts of the Red Planet.
ECU Deputy Vice-Chancellor Research, Professor Paulo de Souza, who worked on NASA's Mars Exploration Rover mission, has discovered mineral clues that had remained hidden in rover data for decades.
By re-examining observations collected by the Spirit Rover over more than 2,000 days on Mars, Professor de Souza identified traces of hematite and altered magnetite in Martian soil.
These minerals are important because they can form when rocks interact with water.
The findings provide fresh insight into the Red Planet's ancient environment and strengthen evidence that water once played a major role in shaping the planet's surface.
Professor de Souza analysed data collected from 32 undisturbed soil sites across Gusev Crater between 2004 and 2010.
By combining hundreds of individual measurements, he created the most detailed iron-mineral profile ever produced for typical Martian soil.
"One of the most important discoveries was finding crystalline hematite in ordinary Martian soil," Professor de Souza said.
"This mineral's widespread presence suggests not only that water was present, but that significant areas of Mars may have once been covered by water."
Scientists had previously believed hematite was mostly absent from these soils.
However, the new analysis suggests the mineral was there all along, but in amounts too small for individual rover measurements to detect.
"The original rover observations were limited by time, power and the gradual aging of the instrument used to collect the data," Professor de Souza said.
"Many measurements were not detailed enough on their own to identify minerals present in very small quantities. By bringing the data together and analysing it in a new way, we were able to reveal information that had been hidden for years."
The new research also supports the idea that much of Mars is covered by a similar layer of dust and soil.
Scientists believe this layer formed over millions of years through wind erosion, extreme temperature changes and the movement of dust across the planet.
Professor de Souza said the discovery highlights the value of revisiting data from past space missions.
"This work shows that important discoveries are not always made by collecting new data," he said.
"Sometimes they come from looking at existing data with fresh eyes and better analytical techniques."
The article, A consolidated Mossbauer spectrum for undisturbed soils from Gusev Crater, Mars, is published online in Interactions by Springer Nature.
