The venerable rover on the red planet may be detecting signs of the aridity of the Martian climate in ancient times.
NASA’s long-running Curiosity mission, which will mark its 10th anniversary on the Red Planet in August, is making its way up the slopes of Mount Sharp (Aeolus Mons) to track Mars’ changing climate over the ages. Over the course of about the last year of its wanderings, Curiosity has noticed that the water-rich mud is giving way to a transition zone filled with salty sulfate. Scientists currently believe that these features determine where the streams dried up and dunes formed, according to a NASA statement. (Opens in a new tab).
What this means is that lake sediments that inhabited the lower slopes are not as common as Curiosity that reaches up the mountain. “Instead, we’re seeing a lot of evidence of drier climates, like dry sand dunes that were sometimes surrounded by currents,” Ashwin Vasavada, Curiosity project scientist at JPL, said in the statement.
Related: 12 stunning photos from the first year of the Perseverance rover on Mars
Besides more sulfates, geological features are catching the attention of scientists. They see sediments likely deposited in piles of “unstable strata”, including one nicknamed “Introduction” by team members.
JPL stated that the area has a complex history, including a story of dry origin as an area filled with sand dunes and some areas that appear to have water-borne sediments.
“Making the story richer and more complex is knowing that there have been multiple periods in which groundwater has been ebb and flow over time, leaving a jumble of puzzle pieces for Curiosity scientists to piece together into a precise timeline,” the officials added in the statement.
And while the rover is still doing well, the Jet Propulsion Laboratory notes that it shows inevitable signs of age, in particular holes on its aluminum wheels that have been navigating Martian terrain in the years since Curiosity’s August 5, 2012 landing.
The left middle wheel, as shown in photos taken on June 2 of this year, has more damage and bigger holes in her pants (treated). The Jet Propulsion Laboratory said the dredgers were unlikely to disintegrate completely, but observed ground testing shows that at worst, the vehicle could drive on its wheel rims if necessary.
Curiosity also had a brief crash in safe mode on June 7 after an unexpected overheating of the device’s control box. The craft exited safe mode after two days on the ground, and team members are investigating the cause.
“They suspect that safe mode is on after the temperature sensor provided an inaccurate measurement, and there is no indication that it would significantly affect rover operations since backup temperature sensors can ensure that electronics inside the rover body do not overheat.” JPL stated.
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