☄️ Discovery of an object on Mars that doesn't belong there

Amidst the flat, fragmented rocks strewn across the Vernodden region on Mars, an isolated block with a peculiar morphology rises. This object, named "Phippsaksla," resembles none of the specimens observed so far in Jezero crater. Its meticulous examination by the instruments on NASA's Perseverance rover reveals a unique chemical signature, opening the trail to an origin far more distant than the Martian soil itself.

This discovery marks a notable milestone for Perseverance. After more than one thousand sols (Martian days) traversing and analyzing local geological formations, the rover is potentially confronted with an external visitor. The presence of such an object, although rare, is not unprecedented on Mars. Nevertheless, it offers scientists a precious opportunity to study, directly on-site, a sample of material from elsewhere. The collected data enriches our understanding of the frequency and nature of impacts on the red planet over time.

A composition revealing a distant origin

The initial analysis of Phippsaksla was conducted using the spectrometer of the SuperCam instrument. The results, published in a mission update, indicate an abnormally high iron and nickel content compared to typical Martian rocks. This association of elements is characteristic of a specific class of meteorites, known as metallic meteorites. These are considered fragments from the cores of differentiated asteroids, celestial bodies massive enough to have melted in their youth, allowing heavy metals to migrate towards their center.

The very morphology of the rock provides additional clues. Its sculpted appearance and resistance to erosion, contrasting with the surrounding rocks, are consistent with the effects of atmospheric passage and high-velocity impact, even in Mars' thin atmosphere. These processes shape and densify the surface of meteorites. The discovery was the subject of a detailed communication on the official Mars 2020 mission website, before being relayed by specialized publications like Space Science Reviews.

Definitive confirmation of its nature will require further investigation. The rover has other tools, such as the PIXL spectral imager, capable of mapping elemental composition with very high precision. These analyses will allow the search for specific minerals, like taenite or kamacite, whose crystalline structure is an undeniable signature of iron-nickel meteorites. This detailed study is essential to rule out a Martian origin, even though it is already unlikely.

A rare visitor in the Jezero landscape

The discovery of Phippsaksla satisfies a curiosity for the Perseverance team. Indeed, other rovers like Curiosity in Gale crater, as well as Spirit and Opportunity, have already identified several metallic meteorites during their missions. The absence of such a find in Jezero, an ancient impact crater showing many small secondary craters, was therefore notable. This late discovery suggests these objects are extremely scattered.

Studying these extraterrestrial fragments directly on Mars presents a considerable advantage. It allows observation of their state of preservation in the Martian environment, without the potential alterations suffered during a fall on Earth. Furthermore, their presence and distribution provide information about the history of meteoritic bombardment on the planet's surface. These data help calibrate models of impact frequency, ultimately enabling the dating of planetary surfaces.

If its status as a meteorite is confirmed, Phippsaksla could potentially join the collection of samples that Perseverance is tasked with collecting and sealing. These sealed tubes are intended to be brought back to Earth by a future sample return mission. Laboratory analysis on Earth would then offer a much more in-depth characterization than possible in situ, perhaps allowing the history of its parent body to be traced.