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.
More on Mars
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.
The report proposes a core mission design called ‘30-Cargo-300’, which would see astronauts landing on Mars for 30 sols before returning to Earth, followed by a cargo delivery and then a 300-sol (or even 500-sol) mission by a second crew.
The mission plan favoured in the report would see astronauts land in a 100km-diameter (62-mile) ‘exploration zone’, with the initial 30-sol mission likely to search for drilling sites for the 300-sol mission, while also bringing home samples from a potentially habitable site.
It’s the most ambitious, science-rich mission design in the report, focused on achieving all high-priority science objectives in one location.
Another campaign prioritises the search for life, targeting a location where deep drilling could reach liquid water beneath the surface.
Samples would be collected, partly studied on Mars, but mostly returned to Earth for examination.
This campaign focuses on seeking life beneath the Martian icy crust and would require deep drilling down to 1.5–5km (1–3 miles). Why so deep?
"Because that’s where liquid water might be," says Dava Newman, Apollo Program professor of aeronautics, astronautics and engineering systems at the Massachusetts Institute of Technology, and a committee co-chair for the report.
"It’s the highest potential for detecting life, and it requires advancements in our technology to make this happen."
A fourth mission architecture, ‘30-30-30’, involves sending three crewed missions to three separate sites on Mars, for 30 sols each (though up to 90 would be possible), to explore volcanic terrain, sedimentary rocks and glaciers in turn. Each of these shorter-stay missions would last about 500–800 days in total.
Life during the journey to Mars
The journey to Mars itself will present significant challenges. Beyond Earth’s magnetic field, crews are exposed to galactic cosmic rays and solar radiation storms.
To protect them from these potentially deadly doses of radiation, spacecraft will need robust shielding and spacious habitats.
"They’re going to need a full-up habitat comparable to the living space on the International Space Station," says Les Johnson, former NASA chief technologist at Marshall Space Flight Center, who worked on Artemis I and led innovation in propulsion, power, lunar landers and life-support systems at NASA.
"It would require something of that size to have enough room for the crew to move around, have some privacy, do their exercising."
That habitat would likely stay in orbit while a lander carried astronauts to the surface.
Surviving the journey is only part of the challenge.
Living on Mars means building a closed system – one that can provide air, water and food in an environment where none are readily available.
Oxygen will likely be produced from the Martian atmosphere itself, which is more than 95% carbon dioxide.
Technologies such as MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment), successfully tested on the Perseverance rover, have already shown that it is possible to extract breathable oxygen from carbon dioxide on Mars.
Food will rely on pre-packaged supplies in these early missions, while water will come from recycling and extraction.
On the International Space Station, astronauts already recycle sweat, urine and moisture from breath into drinking water.
Similar closed-loop systems would be essential on Mars, eventually supplemented by mining subsurface ice where it is accessible.
Mars – a fragile outpost
Even basic human needs become engineering problems. Toilets cannot rely on gravity; instead, they use airflow to remove waste, which is then stored or processed as part of the recycling system.
Fine dust can infiltrate seals, machinery and habitats, posing both mechanical and health risks.
Radiation, however, remains one of the most serious long-term threats.
Without a global magnetic field or thick atmosphere, Mars is exposed to high-energy particles from space, meaning habitats may need to be shielded with layers of Martian soil or built partially underground.
Living on Mars will feel like maintaining a fragile outpost – one that depends on constant vigilance, careful resource management and systems that cannot fail.
Could nuclear power help us get to Mars?
It’s increasingly possible that any crewed mission to Mars will be nuclear-powered.
NASA has traditionally relied on chemical rockets to push spacecraft out of Earth’s orbit and on towards Mars.
However, that approach means long flight times and heavy propellant loads.
Enter the agency’s emerging nuclear‑electric propulsion plans: a compact space reactor called Space Reactor-1 (SR-1) Freedom, slated for launch in December 2028.
Able to generate a steady flow of electrical power to drive high‑efficiency ion or Hall‑effect thrusters, nuclear-electric engines are highly efficient and gradually build up speed to reach far higher velocities than conventional chemical rockets can achieve.
The spacecraft will use a 20kWe reactor fueled by enriched uranium to power advanced electric thrusters, taking around a year to reach Mars.
Once there, concept plans include deploying three autonomous helicopters or drones.
This so-called Skyfall payload of helicopters (much like the Ingenuity drone which flew on the Red Planet 72 times between 2021 and 2024) will land at different locations on Mars to map terrain, analyse slopes and hazards, and search for subsurface water-ice.
The mission is ambitious, but if it works as planned, SR‑1 may be a pathfinder for a new class of deep‑space transport, particularly as NASA plans to share the reactor design for SR-1 Freedom with the commercial space industry.
Beyond reach: the 40-minute silence
Humans on Mars will be truly on their own, cut off from real-time contact with Earth.
Radio signals travel at the speed of light, but even that isn’t fast enough to enable real‑time, back‑and‑forth communication between a Mars crew and Earth.
Depending on the orbital geometry, the one‑way communication delay ranges from about four minutes at closest approach to roughly 24 minutes when the planets are on opposite sides of the Sun.
That means even a single question and reply could take 40-50 minutes, making conversations little more than exchanges of recorded messages.
This delay breaks NASA’s usual human spaceflight protocol, in which a ground controller in Houston can talk a crew through failures in seconds.
On Mars, Mission Control becomes Mission Support. Flight controllers can still run simulations, provide procedures, uplink software patches and review data, but they can’t steer the crew through a leak, fire or computer crash in real time.
For astronauts on Mars, autonomy will be everything. They’ll need to diagnose alarms, reconfigure power systems, fix life‑support glitches and improvise, with minimal guidance from Earth.
That, in turn, shapes everything from training and crew selection to the design of habitats, vehicles and onboard AI assistants, all aimed at enabling humans to make good decisions during the long silences.
Why we're sending humans to Mars
The importance of Mars lies not in the act of landing, but in what it reveals.
If life once existed there, it would suggest that biology emerges readily under the right conditions – that the Universe may be filled with living systems.
If not, it would raise equally profound questions about how rare life might be and how unique Earth could be.
"The first human landing on Mars will be the most significant moment for human space exploration since we first set foot on the Moon over 50 years ago," says Elkins-Tanton.
But for those who go, the experience will not be defined by arrival or that first footstep, but by years
of work: planning, travelling, drilling, analysing, repairing and enduring.
Mars will be understood slowly – one risky sol at a time.
What are your thoughts on plans to send humans to Mars? Let us know by emailing contactus@skyatnightmagazine.com
