Is there life on Mars? Only science will tell, this week on Planetary Radio.

I'm Sarah Alahmed of the Planetary Society with more of the human adventure across our solar system and beyond.

Today we're diving into an exciting new mission concept, the Mars Life Explorer.

Amy Williams, the science champion that helped make this mission a priority in the most recent decadal survey, is here to explain why this mission is so vital and why we hope to send it to Mars sooner rather than later.

Then Bruce Betts, the Chief Scientist of the Planetary Society, will join me for what's up and a celebratory conversation about reestablishing contact with our beloved Voyager 2 spacecraft.

Back in 1975, NASA launched the Viking 1 and 2 missions. These twin spacecraft, which each consisted of an orbiter and a lander, were poised to give humanity the most comprehensive look at the red planet yet.

Before the landing of Viking 1, the only mission to operate on the surface of Mars was the Soviet Union's Mars 3 spacecraft, which touched down just a few years earlier in December 1971.

Unfortunately, Mars 3 stopped working just two minutes after it touched the surface.

But Viking 1 transmitted its first image from the surface of Mars on July 20, 1976, and it was a site that no human had witnessed in such detail.

We saw Mars as it truly was, a red and desolate landscape littered with rocks, but also infinite opportunities to learn more about our place in the cosmos.

While the Viking landers recorded temperatures and analyzed the iron-rich Martian ground and conducted a bunch of chemical experiments, it was the lander's in situ experiments to detect life that still puzzled scientists to this day.

The mission introduced water with nutrients and radioactive carbon to Martian soil samples. If life existed, the hypothesis was that the Martian microbes would consume the nutrients and emit radioactive carbon.

Strangely, that's exactly what the instruments detected. But when the soil was sterilized, the results vanished, and the mystery deepened.

Later missions discovered the presence of perchlorate in the Martian soil, leading to debates about whether this compound might have caused the positive readings as opposed to actual life.

The results from Viking's life detection experiments remain inconclusive to this day, but the proposed Mars Life Explorer mission hopes to carry on that legacy.

The Mars Life Explorer, or Emily Mission, was announced as a priority in the most recent Decadal Survey, which was released in April 2022.

The Decadal Survey is a report prepared every 10 years by the National Academy of Sciences, Engineering and Medicine, at the request of NASA.

It represents the consensus opinion of leading experts in the field, specifically addressing the most pressing scientific questions facing the space community, and outlining a priority list of missions that can answer them.

There are many missions on Mars trying to assess its past habitability, but Emily, like the Viking landers, hopes to take it a step further, and answer the question of whether or not there's still life on the red planet to this day.

Our guest today is Dr. Amy Williams, the science champion for the proposed Mars Life Explorer mission.

She's an assistant professor of geology at the University of Florida, with a specialized focus on the formation and preservation of biosignatures and terrestrial environments.

She has been instrumental in the research that could reveal clues to potential life on Mars.

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