NASA’s Curiosity rover has found the highest amounts of clay in any sample taken so far during its mission to Mars. To celebrate, the rover snapped a selfie as it explored the aptly-named “clay-bearing unit” where the newest samples were taken.
To generate this selfie, 57 different images captured by Curiosity’s Mars Hand Lens Imager (MAHLI) were combined into one panoramic image. The MAHLI is a camera placed on the end of the rover’s robotic arm, and the arm itself was digitally removed from the final image to show the rover in all its Martian glory.
If you look to the left and below the rover in the image, you can see two small drill holes. These two targets are called “Aberlady” and “Kilmarie” and were recently made by Curiosity as it dug through the surface to collect samples. They are the 20th and 21st drill sites for Curiosity on its mission so far.
Curiosity is traveling through the clay-bearing unit as it slowly wends its way up Mount Sharp. This region is of particular interest as clay often forms when water is present, and it is believed that there was water on the surface of Mars billions of years ago. Examining the clay that still exists on the surface could give an indication of whether there were conditions that could have supported life at one point in Mars’ history.
To analyze the samples, Curiosity uses its CheMin instrument (a portmanteau of chemical and mineralogy) which can identify and measure the amount of certain minerals in the Martian rock. Notably, in addition to the clay, the CheMin instrument detected very low levels of hematite in the clay-bearing unit. Hematite was abundant in the nearby Vera Rubin Ridge, where Curiosity was exploring at the start of the year.
These new findings provide compelling evidence there was once water in the region, but researchers still have questions about how water interacted with the rocks. It could be that rocks were formed when water pooled into lakes, with layers of sediment at the bottom. Over time, the sediment formed into the rocks which still litter the surface of the region today.