Rugged, remote and brutally cold.
Tying your shoelaces is challenging at the South Pole - let alone building a runway out of snow.
But that’s exactly what researchers from the University of the Sunshine Coast in Queensland think they may have found a way to do, in a recent article published in the Journal of Cold Regions Engineering.
Using something as simple as coloured dye.
The problem
There is already a 'skiway' at the South Pole. A 3.6km-long strip of snow that services the research station there. But as Dr Adrian McCallum points out, there's a glaring issue with the current facilities.
“They can only land ski-equipped Hercules aircraft at the pole, and they can only carry a limited amount of fuel. But the whole Amundson-Scott research station relies on diesel to run the generators,” Dr McCallum said.
Instead, fuel and other supplies are flown to the warmer coastal airstrips of Antarctica and then towed to the research station via the South Pole traverse road.
“What they'd like to be able to do, is create a runway at the South Pole where they can land a normal aircraft with wheels,” Dr McCallum said.
“It's one of the last great polar logistical problems.”
The science
So why can’t you build snow runways at the South Pole? Dr Greg White says it’s more than a matter of simply shoving snow together.
“Snow strength comes from sintering of the particles, which is partial melting leading to bonds on a microscopic scale. It’s like sugar granules bonding together over time if you leave them undisturbed in a jar,” Dr White said.
“At the South Pole it’s -30°C most of the year and snow only sinters quickly enough to be helpful at about -10°C.”
At the edges of the continent where the summer temperatures are typically -10°C to +5°C, this is possible. But as you head further inland and gain altitude, the temperature plummets to an average minimum of -29°C even in the summer months.
“It might be great for skiing, but it's not much good to land aircraft on.”
The solution
It’s a complex problem that’s stumped polar researchers and engineers for decades.
Past ideas included everything from heating the snow up to mixing it with sawdust to make miniature bricks, but no practical solution has been found.
But the theory behind using coloured dye to create a stronger snow, is surprisingly simple.
“The dye attracts sunlight because its darker, which increases the temperature from -30°C to -10°C, which accelerates the sintering process,” Dr White said.
“This means the snow gets stronger in a reasonable and practically viable time frame, rather than taking years to harden up.”
To test the idea, Dr White and Dr McCallum with the help of student Jaspre Outram, stepped into a freezer simulating South Pole temperatures and shaved down manufactured ice into snow-sized particles consistent with what you’d find on Antarctica.
The snow was packed into beakers and given different concentrations of dye, before being exposed to a lamp emitting light at the same frequency as the sun over the course of several months.
The results backed up the theory.
At the end of the trial, the dye-coloured snow tested as warmer, denser and stronger.
“The next step would be to verify the results with real snow in a large freezer designed for snow research. The dye also needs to be approved for application in Antarctica, which is a protected environment,” Dr White said.
“But if that occurred, it could be done with confidence that the concept is sound.”
Dr McCallum believes the results showed great promise.
“As long as it was done with an inert dye that didn’t cause any environmental harm, I think it’s viable,” Dr McCallum said.
“If we went to Antarctica and sprayed this dye along a 1km x 100m metre wide section, then stood back and let the sun do its thing… I think it could work.
The scientists
So how did two scientists on the sun-soaked Sunshine Coast end up designing airstrips in Antarctica?
For Dr White it comes from a long history of engineering study, specialising in airfields and pavements.
“I actually vaguely knew Greg (Dr White) from his Air Force days. He’s since become Australia's asphalt and airport pavements guru,” Dr McCallum said.
Dr McCallum’s own military history played a part in his decision to dedicate himself to studying snow, ice and engineering, under tragic circumstances.
“I was in the Navy. We were on a Mount Everest expedition in 2001 and there was an avalanche that killed three people, including an eight-year-old girl,” Dr McCallum said.
“That made me want to study the strength of snow, and snow mechanics.
“So, I left the Navy, to join the Army and study civil engineering.”
Their two specialised fields don’t offer a lot of collaboration opportunities.
But their combined knowledge in two very different areas of engineering, has allowed Dr White and Dr McCallum to seek solutions in a place few other scientists can explore.
“Adrian is interested in snow. My work is focused on airport pavements. The overlap is a small niche, and this is not our first foray into snow runways,” Dr White said.
“We wrote a paper a few years ago reviewing the construction and design of snow and ice runways. So this is just furthering that relationship,” Dr McCallum said.
“There are other folks out there who deal with snow roads and snow runways - but arguably you could say we are becoming global experts in our field.”
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