SpaceX is preparing to head there in a few short years and NASA’s moon missions are seen as a stepping stone to the red planet, but the cold, hard truth is this: Mars wants to kill you. Its gravity is detrimental to bones and muscles, it provides little protection from radiation and it’s incredibly cold. If humans ever want to colonize Mars, they’ll have to come up with unique ways to survive there.
Enter “frozen smoke.” An international team of scientists is proposing the use of silica aerogel, sometimes dubbed frozen smoke because of its appearance, to warm up the surface of the red planet enough to support life and melt frozen water. The aerogel is an incredibly lightweight material already being manufactured on Earth and is currently used in NASA’s Mars rovers as insulation.
The study, published Monday in the journal Nature Astronomy, essentially created Mars-in-a-box, simulating the light that hits the planet’s surface in the laboratory and placing a layer of aerogel, around an inch thick, over the top.
“We used a customized solar simulator to reproduce the spectrum and intensity of the sunlight falling on the Martian surface,” said Robin Wordsworth, first author on the study. Wordsworth and his colleagues then measured the temperature and how much UV radiation passed through the aerogel.
He said the experiments were conceived because existing ideas to modify Mars’ environment on a global scale seem “very hard to achieve.” Instead, the team wanted to replicate the effects of Earth’s atmosphere on the distant planet on a much smaller scale.
“Earth’s atmosphere raises surface temperature via the greenhouse effect, and blocks UV radiation via the ozone layer,” he said. “Any solution to habitability on Mars must do these two things, as a minimum.”
They found that the thin layer of aerogel, which looks like a frozen cloud, did just that. It could block UV radiation but allow enough visible light to pass through to warm the surface of Mars above the melting point of water. The aerogel tiles were able to raise the temperature by up to 50 degrees Celsius (122 degrees Fahrenheit).
To complement the lab work, the team also ran computer simulations of how the aerogel shield would fare if placed over Martian ice deposits. Their results demonstrated that “Earth-like temperatures” ranging from 32 to 77 degrees Fahrenheit could be achieved through almost the entire Martian year, which would ensure liquid water was available to anyone at the surface.
So what’s the hold up? We can just fly this stuff to Mars and get colonizing, right?
Not exactly. The team stresses that if Mars is to be made habitable in the near future, there are philosophical and ethical questions that require serious mulling over, especially if Mars still contains life today. If we were to begin transporting humans and, inevitably, microorganisms from Earth to Mars, those invasive species could threaten life already present on the planet. We don’t know yet that Mars currently supports any life, but it has been proposed as an answer to some of Mars’ enduring mysteries. The authors note that creating a self-contained system as described in the paper wouldn’t support life outside of the aerogel-shielded regions.
Wordsworth said he plans to conduct more lab experiments to “explore a greater range of Mars environmental constraints,” in addition to continuing the computer simulation work. Field work is also planned using Mars-like sites here on Earth, where the research team can venture out and test their aerogel shields in the environment.