A new experiment held on board the International Space Station (ISS) has indicated that Mars rovers are unlikely to detect biomarkers on the Red Planet unless they dig deep.
Both Curiosity and Perseverance utilize Raman spectrometers in order to identify organic compounds, using a laser to excite molecules and analyze exactly how they scatter light. However, the research published in Science Advances and led by Mickael Baqué of the German Aerospace Center (DLR) suggested that biological cells have hardly no chance of surviving on Mars’ surface due to the intense ultraviolet radiation coming from the sun.
The researches exposed a sample of molecules to conditions similar to those on Mars for 469 days in the Biology and Mars Experiment (BIOMEX), including seven different types commonly found in organisms. Only three— chlorophyllin, quercetin and melanin — remained detectable after such exposure and even then, the signal from those molecules weakened by 30% to 50% due to the ultraviolet light.
"Ultraviolet [radiation] only penetrates the first few micrometers to millimeters of the Martian surface, so organic compounds and potential biomolecules should be protected beyond these depths," Baqué told press.
As a result, the researchers suggested that the Martian surface would likely appear dead unless the planet has enough life to constantly replenish such biomarkers. Otherwise, the rovers will have to dig under the first few "micrometers to millimeters" to find a layer not affected by the radiation.