Making Mars habitable through silica aerogel
A team of researchers from Harvard University, NASA’s Jet Propulsion Lab, and the University of Edinburgh suggest that regions of the Martian surface could be made habitable with the material silica aerogel, which mimics Earth’s atmospheric greenhouse effect.
Living on Mars is not just something for science fiction authors to fantasise about anymore. Already in the early 1970s, a scientist named Carl Sagan suggested that by vapourising the northern polar ice caps of the planet, which consists of frozen water and CO2, a thin atmosphere could be created.
In 2018, researchers from University of Colorado, Boulder and Northern Arizona University calculated that if all sources available on Mars would be utilised, it would only increase the atmospheric pressure to about 7 per cent of that of Earth, way too little for humans to survive.
Terraforming the entire planet appears to be impossible, which is why the team from Harvard, NASA and Edinburgh took a more regional approach. Through modelling and experiments, they found that a two to three centimetre thick shield of silica aerogel could transmit enough visible light for photosynthesis, block hazardous ultraviolet radiation, and raise temperatures underneath permanently above the melting point of water, without the need for an internal heat source.
The researchers were inspired by the frozen CO2 on Mars’ ice caps, which allows sunlight to penetrate while trapping heat. In summer, this effect creates pockets of warming under the ice.
Silica aerogel is one of the most insulating materials ever created. It is 97 per cent porous, which means that light can penetrate the material, but the interconnecting nanolayers of silicon dioxide slow the conduction of heat significantly. The material is used in a wide range of applications, including NASA’s Mars rovers.
Since the material works passively, it wouldn’t require large amounts of energy or maintenance to keep an area warm over long periods of time.
A next step in the research is to test the material in Mars-like climates on Earth, like the dry valleys of Antarctica or Chile.