Life on Mars using aerogels?
Aerogels are excellent thermal insulators, and a thin layer could make Mars more habitable...
Scientists at Harvard University have shown that aerogels could provide the insulation from ultraviolet radiation and extremely cold temperatures required for life to be sustainable on Mars.
Due to its thin atmosphere, the surface of Mars can reach -100°C, and the ultraviolet radiation levels are considerably higher than on Earth.
This study - published in Nature Astronomy - examined conditions inside a polystyrene bowl covered with a layer of aerogel, in a similar way to covering a bowl with a layer of cling film.
After shining a lamp that simulates sunlight on Mars, the researchers found that the temperature inside the bowl was 50°C higher than outside (for a 3 cm thick aerogel layer). In addition, the aerogel blocked ultraviolet radiation from the lamp to a level that was safe for humans to experience.
Richard Collins, from IDTechEx in Cambridge, described an aerogel as “a highly porous material. If you imagine a gel - which has a liquid and a solid component - and you remove the liquid component, and you’re just left with the solid network... that is an aerogel.” The aerogels used in this study were made from silicon dioxide, the same material that is found in most types of sand.
The network of solid silicon dioxide surrounds thousands of small pockets of trapped air. Aerogels can contain up to 97% air by volume within these small pores in the solid structure. Since this air is trapped, and cannot flow through the material very easily, the conduction of heat is poor. This large network of air pores give the aerogel its good thermal insulating properties.
The results from the study suggested that - with a thin layer of aerogel insulation - life might be able to survive on Mars. However, “it was more a hypothetical. There are so many barriers to actually making this happen,” said Collins.
Since this study was conducted in a laboratory - on Earth - the next challenge is thought to be getting these aerogels onto the surface of Mars.
Collins said, “the paper does say that there would be serious manufacturing challenges that would have to be shifted. They are exceptionally light, but then you have got volumetric space to consider, as well as the brittleness of actually transporting it.”
Aerogels are well known in the materials science world for being extemely brittle. The large volume of air, combined with the thin network of silicon dioxide, means that cracks can form very easily. It is clear that the transport of these materials into space is going to prove a challenge.
Manufacturing the aerogels on Mars was hypothesised as an alternative option, but this may not be easy; conditions on the surface of Mars are very different to a laboratory on Earth.
Whilst the study is believed to be an exciting first step towards making life on Mars more feasible, there is still a long way to go!