SETTING foot on Mars: it’s the stuff of science fiction.

But it will take hard science to turn it into reality.

Getting there represents the greatest challenge humanity has ever undertaken.

Staying there, however, would make even that achievement pale into insignificance.

Real progress is being made.

But there’s still a long, long way to go.

Can the world muster the will, the inspiration — and the cash — to get us there?

Professor of Astrobiology at the University of New South Wales Dr Malcolm Walter thinks so. With a caveat or two.

“I’ve been interested in this subject since the 1970s, and it’s always been 20 years away. But I’m convinced it will happen,” he says.

“I’d not be at all surprised if people were on Mars within 20 years. It is inevitable someone will do it — even if it’s not one of the space agencies.”

NASA says it can afford to put a small crew on Mars by 2039 — but only if it abandons the International Space Station.

But China also has plans, the first step of which involves sending a rover there in 2020. Europe has already sent several probes to the red planet. Unfortunately, most have failed. India put a probe in orbit in 2013 while Japan is looking at putting a lander on one of Mars’ small moons to bring back a sample. Even the United Arab Emirates is planning an orbiter to examine its weather.

Could such a diverse collection of nations pull together?

While established partners such as NASA and the European Space Agency are likely to work together, Dr Walter says he is seeing a return of the international space race mentality.

“National pride has again entered the formula,” he says. “I can see that as at least partly driving any program to get to Mars — or anywhere else for that matter.”

Entrepreneurs such as Elon Musk are also taking up the challenge. He boasts he can put privately-funded humans on Mars by 2025.

The red planet beckons. Few, however, have detailed the challenges to be overcome — let alone provide a blueprint on how to get there, and stay there.

ASTRONOMICAL HURDLES

Our robot invasion of Mars has already begun. But it’s suffered quite a few setbacks, with roughly half the missions sent there suffering catastrophic failure.

The biggest and most successful of these, the Mars Science Laboratory mission, helps put the challenge of establishing a colony there in perspective. This probe unleashed the Curiosity Rover. All up, its payload was the size of a small car and weighed 900kg.

Transporting the building blocks for a manned colony would require a much, much larger effort.

“We’re talking tens of tonnes,” Dr Walter says. “Getting that safely on the ground would be a huge challenge.”

The risk to astronaut lives is the most likely deal-breaker, he says.

“I can’t see a government sending anyone there quickly because of all the political fallout such a tragedy would raise. But someone like Musk might just be able to do it.”

Air. Water. Food. Tools. Radiation shielding. Everything we need to live on Mars we’d need to carry there. At least initially.

Balancing the stark equations of supply and demand will always be on every astronaut’s mind.

Then there’s Mars itself.

A balmy day will present you with a dim Sun — pumping out enough radiation to dangerously expose anyone bounding along the surface under one-third of Earth’s gravity.

The impact of that microgravity on our bodies is itself not fully understood.

The gentle 12km/h breeze can rapidly ramp up to a 90km/h gale — though it won’t carry much punch, as the atmosphere is just one per cent the thickness of Earth.

But it can carry lots of fine red dust.

In that dust is perchlorate, a toxin that can upset the human thyroid gland.

BEACHHEAD

In October last year, the Lunar and Planetary Institute in Houston, Texas, looked at potential landing sites. It identified about 50.

Criteria included a large area without boulders, dunes or craters. Yet scientifically significant terrain must be within a 100km radius. The site should be able to sustain between three and five landers, with their four-to- six person crews, for up to 500 sols (Mars days).

“We care deeply about whether the site is going to kill us and whether we can perform the assigned work,” NASA astronaut Stanley Love told National Geographic.

So far the primary prerequisite appears to be underground ice. Such a reservoir would not only provide vital drinking water. It would be a necessary part of any construction work, as well as the synthesis of fuel. While we know such subterranean ice exists on Mars, it is not extensively mapped.

The probes necessary to do so are only now in the blueprint stage. Then it needs to be established if this water can be made fit for human consumption.

Also necessary are easily obtainable Martian resources, such as minerals and even the kinds of rock suitable for construction work.

In the ‘nice’ category is the presence of a small, deep crater or two. Better yet, caves. It is hoped these can quickly be adapted into weather and radiation-proof accommodation.

“The best chance is to go to the caves,” Dr Walter says. “We know where lava tubes are, and they can be very large. So why try to build something when you’ve got caves there anyway that are easily accessible?”

All this can only be established by carefully surveying potential landing sites with robotic landers.

We have proven the effectiveness of Mars rovers. We have potential landing sites.

Now what is needed is a pairing of the two.

No such survey is yet in the works.

TOEHOLD

Dr Walter says the idea of colonising Mars is still very much in the realms of science fiction.

While possible, the enormity of the challenge is yet to be fully recognised, yet alone addressed, he says.

Once radiation-shielded accommodation is established and a water supply secured, colonists could set their minds towards the holy grail of self-sustainability.

“Water is not going to be a constraint in my mind,” he says. “It will be micronutrients.”

Carbon dioxide will need to be harvested. This, with water, can be used to manufacture oxygen and propellant.

Melting subterranean ice, extracting it and filtering it will be a complex process.

“The issue is getting to it, and if you have to drill that requires a lot of energy,” Dr Walter says. “But if you can find it near the surface you can harvest it fairly easy.”

Then there’s keeping oxygen production and air filtration systems constantly running.

“I don’t see a colony being established,” Dr Walter says. “I see something like an Antarctic research station being set up as a first step. Even that would be optimistic. A visit of a few days or weeks is feasible for the next few decades, but no longer at the moment.”

THE HUMAN FACTOR

Plenty of effort has been invested into understanding human behaviour and needs for extended periods in confined spaces. This is because of parallels with the military’s submarine service and isolated research stations in Antarctica.

When it comes to actually living in space, it largely remains a whole new world.

Radiation is an enormous concern. Recent research showed that those who travelled to and around the Moon during the Apollo program (a trip measured in days, not months) had their lives shortened by the equivalent of several years.

“Cosmic rays can kills us,” Dr Walter says. “As will ultra-violet radiation. It will be a huge problem, as will providing the heavy shielding needed to protect people from it.”

Space station stays also hint at potential problems with vision, digestion and attention span.

Then there are the matters of the mind.

“Basically, we’re looking into how to keep them alive and sane … not wanting to kill each other in a long Mars mission,” Kim Binstead of NASA’s year-long isolation mission HI-SEAS told National Geograpic.

Dr Walter thinks human behaviour is the least of our concerns.

“There’s been a lot of research over the decades on mental health and things like that,” he says. “It’s the things we haven’t thought of that will give us headaches.”

There have been several complex simulations of the technical and psychological challenges involved in sending a crewed mission to the red planet. While the psychological effects of isolation in a simulated spacecraft were severe, they appear to have been manageable — if the team had been carefully selected.

But there remains one outstanding element in all these simulations, despite being on the ISS, in mountainous deserts or remote parts of Antarctica.

None are really all that much like Mars.