While the Martian novice Perseverance was unable to take samples of the Martian soil the first time, the old-timer Curiosity, it seems, has been exploring for nine years not what scientists expected.
Curiosity landed at Gale Crater in August 2012 and has since traveled over 150 km along the bottom of the crater and the slopes of Mount Sharp, which rises in the center, more than 150 km.
Pre-rover data suggested that part of the crater in the distant past could have been filled with a huge lake. The estimated age of the crater at 3.5-3.8 billion years, as well as the estimated lifetime of the lake in tens of millions of years, gave scientists hope that now traces of ancient life on Mars can be found in the crater rocks. And all these nine years, the rover has been finding confirmation that there really was a lake in the crater in the past.
However, a recent study by specialists from the University of Hong Kong indicates that the past of Gale Crater may have been somewhat different. In short, the study suggests that there was not one huge lake in the crater, but several small ones. And then a lot of sediment, which the rover explored, got into the crater due to wind or volcanic activity, and then changed under the influence of acid rain.
The problem is that small lakes, most likely, have existed in the crater for only a few tens of thousands of years, which is probably not enough for the emergence of a large number of living organisms. At least if we assume that in the distant past there were only primitive life forms on Mars.
If everything was exactly like that, the Curiosity rover traveled for nine years in far from the most successful terrain from the point of view of its main task.
On the other hand, this is only one study, so, as is often the case in such cases, it is too early to put an end to it. Moreover, the rover itself can work for a long time.