When it comes to Martian rocks, details matter. NASA intends to bring tiny rock samples collected by the Perseverance rover back to Earth for study. This means tracking not only where the Jezero samples were taken from, but also their original orientation in the host rock. To do this, the rover is engaged in a small physical graffiti on the red planet.
In June, Perseverance used the laser portion of its mast-mounted SuperCam to etch three L-shaped dots into a rock. But this is not free graffiti. There is a good scientific reason.
SuperCam principal investigator Roger Vince described the L as “the first letter laser-etched on Mars” in Thursday’s mission update, which details why it was necessary.
In search of ancient traces of life
The rover is studying an ancient river delta that could be its best chance of finding evidence of past microbial life on Mars. This means that the rock samples collected there are of particular importance.
In addition to searching for life, the returned rocks could also help researchers piece together the history of Mars’ magnetic field and its effect on the planet’s atmosphere. Scientists studying this question want to know the orientation of the rock pieces “in order to understand the original directions of the magnetic domains in the samples. This is where laser marking technology comes into play.
As Vince points out, it is easy to determine the orientation of rock samples that have easily recognizable features. “However, if the surface is fine-grained, there may be nothing to indicate its original orientation. In this case, we have to make artificial marks on the surface,” he wrote. The fine-grained rock in the delta region was an ideal place to test this method.
The team chose the capital letter L as a simple and effective way to indicate the direction of travel. “Because the test was definitive, we are ready to use this procedure for labeling future samples,” writes Vince.
The rover could use its writing skills to carve all sorts of messages into the Martian rocks (like “Percy was here”), but NASA wants to use the mobile lab’s energy more for science, not nonsense. Perseverance may not venture beyond L in the alphabet, but that small letter could prove to be very important for a sequel.
CNET.com article adapted by CNETFrance