Biosignature stability in space enables their use for life detection on Mars

TLDR

Mars rover missions use Raman spectrometers to detect biomolecules, but the stability of Raman‑detectable biomolecules in the Martian environment remains uncertain, complicating result interpretation. The study aimed to quantify the stability of Raman‑detectable biomolecules by exposing seven compounds for 469 days to a simulated Martian environment aboard the International Space Station. Seven biomolecules were exposed for 469 days to a simulated Martian environment outside the International Space Station. UV radiation markedly altered Raman spectra, whereas shielding caused only minor changes, demonstrating that biomolecules remain detectable by Raman spectroscopy in Martian regolith analogs after prolonged space exposure and supporting subsurface biosignature searches.

Abstract

Two rover missions to Mars aim to detect biomolecules as a sign of extinct or extant life with, among other instruments, Raman spectrometers. However, there are many unknowns about the stability of Raman-detectable biomolecules in the martian environment, clouding the interpretation of the results. To quantify Raman-detectable biomolecule stability, we exposed seven biomolecules for 469 days to a simulated martian environment outside the International Space Station. Ultraviolet radiation (UVR) strongly changed the Raman spectra signals, but only minor change was observed when samples were shielded from UVR. These findings provide support for Mars mission operations searching for biosignatures in the subsurface. This experiment demonstrates the detectability of biomolecules by Raman spectroscopy in Mars regolith analogs after space exposure and lays the groundwork for a consolidated space-proven database of spectroscopy biosignatures in targeted environments.