After a year and a half of waiting since the Perseverance rover landed on our nearest planetary neighbor, new data is coming — and with some surprises.
The rover, the size of a car and carrying seven scientific instruments, has been exploring Mars’ 30-mile-wide Jezero Crater, a once lake and ideal location for evidence of ancient life and information about Mars. Earth’s geology and climate past.
In a paper published today in the journal scientific progress, a team of researchers led by UCLA and the University of Oslo found that the rock formations at the bottom of the crater, as observed by the rover’s ground-penetrating radar instrument, were unexpectedly sloping. The slope, thickness and shape of the sloping sections suggest that they either formed from slowly cooling lava or were deposited as sediments in the former lake.
Perseverance is currently exploring the delta on the western edge of the crater, where a river once fed the lake, leaving behind a lot of dirt and rocks picked up along the way. As the rover collects more data, the researchers hope to unravel the complex history of this part of the red planet.
“We were very surprised to find the rocks piled up at an oblique angle,” said David Page, UCLA professor of Earth, planetary and space sciences and one of the principal investigators of the Mars Subsurface Experiment Radar Imager, or RIMFAX. Horizontal rocks are seen at the bottom of the crater. The fact that they slope like this requires a more complex geological history. They may have formed when lava rose to the surface, or, they may represent older delta sediments buried at the bottom of the crater .”
Most of the evidence the rover has collected so far points to the origin of igneous rocks or melts, Page said, but based on the RIMFAX data, he and his team haven’t been able to determine how the sloping layers formed. RIMFAX acquires images of subsurface features by emitting a series of radar waves beneath the surface, which are reflected by rock formations and other obstacles. The shape, density, thickness, angle, and composition of subsurface objects affect how radar waves bounce off, creating a visual image of subsurface objects.
During Perseverance’s initial 3-kilometer traversal, the instrument acquired continuous radar images that revealed electromagnetic properties and bedrock formations (the arrangement of rock layers) at a depth of 15 meters, or about 49 feet, of the Jezero floor. The image revealed ubiquitous layered rock formations, including rock formations that sloped up to 15 degrees. Complicating the mystery is that within these sloping areas there are puzzling, highly reflective rock formations that actually slope in multiple directions.
“RIMFAX gave us a view of the Martian formations, similar to the highway road cuts you see on Earth, and sometimes tall rock formations can be seen on hillsides as you drive past,” Page explained. “Prior to Perseverance’s landing, there were many assumptions about the exact nature and origin of the material on the crater’s ground. We have now been able to narrow down the possibilities, but the data we have obtained so far suggest that the crater’s historic crater floor may be larger than ours Expected to be much more complicated.”
The data collected by RIMFAX will provide valuable context for the rock samples Perseverance is collecting that will eventually be brought back to Earth.
“RIMFAX gave us the backstory of the samples we were going to analyze. It’s exciting that the rover’s instruments are generating data and we’re starting to learn, but there’s more to be done,” Page said. “We landed at the bottom of the crater, but now we’re heading towards the actual delta, which is the main goal of the mission. It’s just the beginning of what we hope to learn about Mars soon.”
The paper, “Ground Penetrating Radar Observations of Subsurface Structures at the Floor of Mars’ Jezero Crater,” is one of three published concurrently and discusses some of Perseverance’s first data.
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Svein-Erik Hamran et al., Ground Penetrating Radar Observations of Subsurface Structures at the Floor of Jezero Crater on Mars, scientific progress (2022). DOI: 10.1126/sciadv.abp8564
Courtesy of UCLA
Citation: First Underground Radar Image of Mars Perseverance Rover Reveals Some Surprises (25 Aug 2022), 25 Aug 2022 from https://phys.org/news/2022-08-underground-radar -images-mars-perseverance.html retrieved
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