Kiwi scientists are helping answer one of this century's most tantalising questions: is there life on Mars?

Humans will likely set foot on the red planet within the next few decades - Nasa is under presidential orders to land astronauts by 2033 – but in the meantime, scientists are investigating whether Mars could bear any form of life.

Next year, Nasa and the European Space Agency will embark on missions to deploy rovers on the planet's surface, where they'll drill into refuges where simple microbial life might still exist.

Yet part of the answer to that mystery might already lie here on Earth.

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With brutally high UV radiation exposure and incredibly salty soil that receives no rainfall, Chile's Atacama Desert is one of the most extreme places on the planet.

It's also considered one of closest matches we have to Mars, making it an ideal testing ground for future missions.

Nasa recently used it to see whether a robotic drill and sampling device mounted on a prototype rover could recover soil samples down to a depth of 80cm.

That was crucial because any life on Mars would have to occur below underground to escape the harsh conditions on the surface.

Back in New Zealand, AUT scientists Dr Stephen Archer and Dr Kevin Lee processed and analysed samples sent back from the desert.

They found the soil contained unusual and highly specialised microbes distributed in patches, which they linked to the limited water availability, scarce nutrients and geochemistry of the soil.

The microbes were adapted to high salt levels, similar to what may be expected in the Martian subsurface.

Nasa views the Atacama desert as one of the closest matches to Mars on this planet and used it to test a prototype rover. Photo / David Wettergreen
Nasa views the Atacama desert as one of the closest matches to Mars on this planet and used it to test a prototype rover. Photo / David Wettergreen

"What we essentially found was that life [on Mars] is not necessarily going to be everywhere – so we'll need to know the best places to start looking for it when we get there," Archer said.

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The study's leader, Professor Steve Pointing, formerly of AUT and now based at Yale-NUS College, said the microbes were very different from those previously known to occur on the surface of deserts.

The findings, published in the journal Frontiers in Microbiology, will aid the search for evidence of signs of life during future planned missions to Mars.

"Finding life or even traces of past life will address one of the greatest scientific questions of all time; whether life evolved on more than one planet," Pointing said.

"If life is found on Mars, it improves the chances of discovering life elsewhere in the galaxy."

Later this year, another team of AUT scientists will travel to the Atacama for a joint project with the famous Search for Extraterrestrial Intelligence (Seti) Institute programme.

The team, led by Associate Professor Barbara Bollard, will use drones mounted with special cameras that can detect spectral signatures from plant species below.

Microbes collected from the Atacama were adapted to high salt levels - similar to what may be expected in the Martian subsurface. Photo / David Wettergreen
Microbes collected from the Atacama were adapted to high salt levels - similar to what may be expected in the Martian subsurface. Photo / David Wettergreen

They've already honed the high-tech approach in two of Earth's other extreme spots: Africa's Namib desert, and Antarctica.

LIFE ON MARS

• Mars could have once harboured life and there is some conjecture that life might still exist there today.

• About 3.8-3.5 billion years ago, Mars and Earth were much more similar, and evidence from Mars missions suggest Mars may have been much warmer and wetter than we observe it to be today.

• Because water is key to life as we know it, earlier Mars missions were designed to "follow the water". Progressive discoveries related to evidence of past and present water in the geologic record make it possible to take the next steps toward finding evidence of life itself.

• Future missions will be driven by new technologies allowing us to explore Mars in ways we never have before, resulting in higher-resolution images, precision landings, longer-ranging surface mobility and even the return of Martian soil and rock samples for studies in labs here on Earth.