Europe's upcoming Mars rover mission has received an unexpected boost in its search for signs of ancient life. The Rosalind Franklin rover, scheduled to launch in 2028, will land in Oxia Planum, a vast clay rich plain that formed in water billions of years ago. Two new studies have revealed that natural Martian processes could deliver organic rich materials directly to the rover. These new findings, presented at the joint Europlanet Science Congress and American Astronomical Society meeting in Helsinki, show how rockfalls and ancient floods could bring previously inaccessible organic materials within the rover's reach.
Dr Aleksandra Sokołowska from Brown University and Imperial College London has identified 258 rockfalls scattered across the rover's landing region. By using high resolution imagery from NASA's Mars Reconnaissance Orbiter, the team were able to spot give away signs of the geological events such as great big grooves in the Martian surface that were several metres deep and stretch for 500 metres. The falling rocks that are thought to have created the grooves, range in size from 2.5 to 8 metres across.
"The discovery of rockfalls in Oxia Planum opens up the exciting possibility for the rover to increase the diversity of its samples with material that would otherwise be inaccessible,” - Dr Aleksandra Sokołowska from Brown University.
These fallen boulders are particularly valuable because they were previously embedded high up on slopes, partially shielded from the intense space radiation that constantly bombards Mars. This protection could mean that organic molecules within the rocks have survived intact, something that scientists hope to find when searching for evidence of ancient Martian life. The deep tracks carved by these rolling stones also expose material from metres below the surface, providing the rover with fresh samples that haven't been weathered by eons of Martian conditions without the need to dig.
Meanwhile, evidence has been uncovered that the clay rich sediments in Oxia Planum didn't form locally, but were transported from elsewhere on Mars over 3.5 billion years ago through a series of ancient floods. By studying crater walls throughout the region the team discovered multiple alternating layers of different clay types. The pattern reveals that craters at lower elevations have thicker clay layers than those at higher elevations, and the layers generally get thicker as you move downslope from ancient highlands to the northwest.
The multiple layers suggest repeated episodes of flooding in cyclical bursts of water that spilled into Oxia Planum during Mars' somewhat wetter past. It’s possible therefore that the clays could preserve organic molecules from a much wider range of ancient Martian environments than previously thought. The combination of rockfall materials and transported clay layers create two new options for studying and hopefully discovering signs of ancient life. Whether through rocks that tumbled from radiation shielded slopes or clay sediments that journeyed across the planet billions of years ago, Mars appears to have created its own delivery service for the very materials scientists most want to study.
Source : How the Stuff of Life Could Be Brought to Europe’s Mars Rover by Rockfalls and Ancient Floods