[tivert]

> But what puzzles me is why we have never followed up with any further experiments to try and detect life? After the Viking missions we never conducted any further experiments that could rule out any other possible chemical reactions to get closer to confirming the presence of microbial life.

According to Wikipedia, the radiation levels are too high:

https://en.wikipedia.org/wiki/Life_on_Mars#Cosmic_radiation

> Even the hardiest cells known could not possibly survive the cosmic radiation near the surface of Mars since Mars lost its protective magnetosphere and atmosphere.[63][64] After mapping cosmic radiation levels at various depths on Mars, researchers have concluded that over time, any life within the first several meters of the planet's surface would be killed by lethal doses of cosmic radiation.[63][65][66] The team calculated that the cumulative damage to DNA and RNA by cosmic radiation would limit retrieving viable dormant cells on Mars to depths greater than 7.5 meters below the planet's surface.[65] Even the most radiation-tolerant terrestrial bacteria would survive in dormant spore state only 18,000 years at the surface; at 2 meters—the greatest depth at which the ExoMars rover will be capable of reaching—survival time would be 90,000 to half a million years, depending on the type of rock.[67]

[baja_blast]

People have said the same thing many times yet we keep discovering extremophiles thriving the some of the most hostile environments. And in 2020 they conducted an experiment on the ISS that exposed Earth bacteria to direct cosmic radiation for 3 years and it turns out they survived https://www.smithsonianmag.com/science-nature/scientists-dis.... And this was just Earth bacteria that did not evolve under these conditions, any remaining microbes on Mars would have developed adaptions to survive in such conditions.

[Qem]

So we just need to find a recently excavated impact crater, a few thousand years old, and send a probe there, to inspect freshly exposed layers.