Mars spacecraft may have to dig deeper than thought to find traces of life

"The results also indicate that the complex organic molecules that the Mars rovers Curiosity and Perseverance have discovered, which intrigue scientists but are not indicators of life, may have been altered over time by radiation exposure.

The team's research was published June 26 in the journal Astrobiology."

Good to see some more constraints here concerning life on Mars. Other reports I read indicate flowing water makes it hard to form complex proteins and organic molecules as well. Ancient Pilbara rocks provide a glimpse into cradle of life on Earth,, "In the hot springs they analyzed, Martin's team found the chemicals necessary for life to begin from non-life—a phenomenon known as "abiogenesis." The findings are evidence against the popular theory that life sprung from deep sea hydrothermal vents. In the enduring theory, it's thought that the heat and mineral-rich water in the hydrothermal vents attracted a huge diversity of microbial life, creating the ideal conditions where live organisms could form. But according to Martin, the deep sea vent hypothesis has an Achille's heel: water."

So now we have more constraints, cosmic rays, radiation, and water. I will add here, the Faint Young Sun too. Mars should be very cold.