We get humans to Mars. What then? Here's what we'll really do on the Red Planet – and why it could solve the greatest mystery in science

 Staying alive. That’s what the priority will be each morning for the first humans on Mars.

Astronauts will start each day – or sol, as a day on Mars is called – by checking life-support systems, monitoring their physical condition and assessing their mental health.

Only then will the work begin.

Here's what humans will really do on Mars – if we ever get there.

Why Mars is so dangerous

Living and working on Mars will mean going outside into one of the most hostile environments humans have ever faced.

In pressurised suits, crews will step onto a surface where the pressure is only 0.6% that of Earth, where radiation is ever-present and fine dust clings to everything.

Their aim will be to drill and collect samples, but even walking will feel unfamiliar: in Mars’s gravity, just 38% that of Earth, movement becomes a controlled skip, rather than a natural stride.

If the mornings are about survival, the afternoons will be spent analysing samples inside compact laboratories.

The evenings will be for maintenance – clearing dust from seals and instruments, repairing worn components and preparing for the next sol.

For the first humans on Mars, life will be repetitive, relentless and, from a scientific point of view, hugely rewarding. 

Mission goals: finding life

At the centre of every Mars mission concept lies a defining question: did life ever exist there?

It’s a question that has shaped a new report from the USA’s National Academies of Sciences, Engineering and Medicine.

"This is the millennia-old question – are we alone in the Universe?" says Lindy Elkins-Tanton, a planetary scientist and co-chair of the Committee on a Science Strategy for the Human Exploration of Mars. “It is our top science objective on Mars.” 

At the heart of the report is the search for evidence of past or present life, alongside signs of habitability and prebiotic chemistry.

Scientists will aim to reconstruct Mars’s environmental history by studying its water and carbon dioxide cycles, mapping its geology and identifying environments – such as ancient lakebeds or volcanic regions – where life might once have thrived.

Researchers will also study how the Martian environment affects astronauts over time, including both their physical and mental health.

After all, there are risks from radiation, toxic dust and microbial changes within the closed habitats they will need to live in.

Long-term experiments will also explore how plants and animals grow and reproduce, helping to assess whether sustainable ecosystems – and eventually human settlements – could one day be possible.

Any human mission would also investigate how to use Mars itself as a resource.

By studying local materials such as water-ice and atmospheric gases, astronauts will test technologies for producing fuel, air and water on site.

But they’ll also need to learn about Martian dust storms – which can engulf the entire planet for months – and other hazards that must be understood if a permanent human presence on the Red Planet is ever to be sustained.

Investigating whether life ever existed on Mars, however, will remain the highest-priority task.

The search is not for visible organisms, but for biosignatures – subtle chemical or structural traces preserved in rock.

Mars is thought to retain a record of its wetter past, especially in sedimentary deposits and subsurface ice.

Astronauts will drill into these materials, extracting cores and analysing them for organic molecules, isotopic patterns and mineral structures that might hint at biological activity.

Crucially, they’ll drill much deeper than any rover could – perhaps as deep as 5km (3 miles). 

What happens to those samples next is just as important. Samples collected on Mars are intended to be returned to Earth, where far more sophisticated laboratories can examine them in detail.

"Wouldn’t we love it if we sent a person up there and they found a fossil?" says Elkins-Tanton.

"But that is wild, wishful thinking. It’s got to come back to Earth where we can all look at it, and we can all argue about it, and we can all measure it in different ways. That’s the only way to reach an answer."

The Mars science plan in detail

Reaching Mars is governed by orbital mechanics. Launch windows occur roughly every 26 months, when Earth and Mars are closest.

Even then, a journey using conventional chemical propulsion takes 6–9 months.

That constraint defines the details of the mission design in the report, down to the size of the crew.

It means that 4–6 astronauts must either remain on Mars for extended periods or carry the fuel needed for an early return – a costly trade-off. As a result, mission timelines stretch into years.