NASAmost recent Mars rover begins to study the soil of an ancient crater that once housed a lake.
NASA’s Perseverance rover has been busy serving as the communications base station for the Ingenuity Mars helicopter and documenting the rotorcraft’s historic flights. But the rover was also busy focusing its scientific instruments on rocks that lay on the floor of Jezero crater.
The information they reveal will help scientists create a timeline of when an ancient lake formed there, when it dried up, and when sediment began to accumulate in the delta that formed there. long ago in the crater. Understanding this timeline should help date rock samples – to be collected later in the mission – that might preserve a record of ancient microbes.
A camera called WATSON at the end of the rover’s robotic arm took detailed shots of the rocks. A pair of zoomable cameras that make up the Mastcam-Z imager on the rover’s “head” also surveyed the terrain. And a laser instrument called SuperCam zapped some of the rocks to detect their chemistry. These and other instruments allow scientists to learn more about Jezero Crater and focus on areas they would like to study more in depth.
An important question scientists want to answer: whether these rocks are sedimentary (like sandstone) or igneous (formed by volcanic activity). Each type of rock tells a different type of story. Certain sedimentary rocks – formed in the presence of water from rocks and mineral fragments like sand, silt and clay – are better suited to preserve biosignatures or signs of past life. Igneous rocks, on the other hand, are more precise geological clocks that allow scientists to create an accurate timeline of an area’s formation.
A complicating factor is that the rocks around Perseverance have been blown away over time and covered with younger sand and dust. On Earth, a geologist can trudge through the field and break a rock sample to get a better idea of its origins. “When you look inside a rock, that’s where you see the story,” said Ken Farley of Caltech, Project Perseverance scientist.
Although Perseverance does not have a hammer, it does have other ways of looking at the dust of the millennia. When scientists find a particularly attractive location, they can reach out with the rover’s arm and use an abrasion to grind and flatten the surface of a rock, revealing its internal structure and composition. Once done, the team gathers more detailed chemical and mineralogical information using arm instruments called PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC (Scanning for Habitable Environments with Raman & Luminescence for Organics. & Chemicals).
“The more rocks you look at, the more you know,” Farley said.
And the more the team knows, the better the samples they can ultimately collect with the drill on the rover’s arm. The best will be stored in special tubes and deposited in collections on the surface of the planet for a possible return to Earth.
Learn more about the mission
A key focus of Perseverance’s mission to Mars is astrobiology, including looking for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and hide Martian rock and regolith (broken rocks and dust).
Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for further analysis.
The Mars 2020 Perseverance mission is part of NASA’s Moon-to-Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.
JPL, which is managed for NASA by Caltech in Pasadena, Calif., built and manages the operations of the Perseverance rover.