Mars is a harsh planet.
Between its lack of a breathable atmosphere,
no protection from UV rays,
and temperatures that can range from a pleasant 20 to a hellish minus 153 degrees Celsius,
Mars ain’t the kind of place to raise your kids.
Science fiction thinks we can solve these problems with terraforming;
you know, radically engineering the planet’s climate to make it livable,
even though we can’t control the climate of the perfectly liveable planet we’re on right now.
No, a life on Mars will probably have to be lived indoors,
but we may have just the wonder-material to make that possible.
The material in question is silica aerogel, also known as frozen smoke.
At the nanoscale, aerogel has a sponge-like structure made of silica oxide.
Silica is the same material usually found in glass, so like glass aerogel is translucent.
But its porous structure means it’s 1000 times less dense than glass.
Filling in those nanoscopic pores is just air,
and it can make up as much as 99.8% of the material, making it the lightest solid in the world.
All these properties got scientists thinking that it may make an ideal material for a greenhouse on Mars.
They got the idea from a process that’s occurring there naturally already,
called the Solid-State Greenhouse Effect.
Mars has ice caps made of frozen carbon dioxide, or what you might know better as dry ice.
The solid CO2 traps heat in the soil underneath it, and in the spring, this warming turns the CO2 to gas.
It spouts out of the surface like a geyser, spraying regolith up with it
and leaving dark patches we can see from space.
So researchers asked themselves if there was a material that could produce a similar effect,
and they landed on silica aerogel.
Because it’s translucent, light can still pass through it, allowing for photosynthesis underneath.
But because of what its made of and how its structured, it makes an incredible insulator.
It’s 39 times more effective than fiberglass—
in fact, aerogel has already been used for this purpose on Mars.
It’s helped keep components warm on every rover we’ve sent to the red planet.
Better still, the material also turns away UV rays that cause sunburns and damage DNA.
So far on paper, aerogel sounds like a key piece of a permanent Martian settlement.
Of course we don’t shoot things off to other planets just because it sounds nice on paper,
we're not Elon Musk,
so the scientists decided to set up an experiment as a proof of concept.
They shined a light tuned to mimic the sunlight on Mars
at a 2.5 centimeter thick sheet of aerogel in a polystyrene box,
and found it increased temperatures as much as 50 kelvin.
They speculate that if they could develop aerogel that was less smoky and let more light through,
they could get that number into the hundreds.
More warming means the aerogel can be placed at higher latitudes,
where there’s more frozen groundwater to melt,
but even the warming from current materials could be used to grow plants.
We could make greenhouses out of it to grow food on Mars,
or simply place it in the soil to encourage algal growth.
But as well-suited as aerogel is for the task, it’s not perfect.
Remember how it’s made from the same stuff as glass?
Well, that also makes it extremely stiff and brittle.
Either we’d have to combine it with other materials like plastic,
or we’d have to institute an extremely strict “no golfing” policy on Mars.
Sorry, Alan Shepard.
So, the scientists are going to keep experimenting.
The next step is to take it to the most Mars-like environments on Earth,
like South America’s Atacama Desert or Antarctica,
to see if aerogel really can make these kinds of harsh environments more hospitable.
If it passes muster there,
maybe one day small bits of Mars could be the kind of place to raise your kids, after all.
Just don’t play baseball little Timmy or a homerun might doom us all.
Thanks for watching!
If you want to learn more about living on Mars,
check out this Focal Point episode on how engineers are building 3D printed habitats for the red planet.
Would you live in a greenhouse on Mars even if it meant you could never return to Earth?
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See you next time on Seeker!