Aerogels are a type of porous solids that are mostly known for their extreme low densities. This means that because they are open-porous, they are impermeable to gas. Aerogel was created by Dr. Samuel Stephens who discovered it between 1929 and 1930 (A, 2000). Aerogels are the lowest density solids; like the silica aerogel that was three times heavier than air, and, when extracting the air from its pores, can be lighter than it. Aerogels are also transparent because of the presence of silica particles smaller than the wavelength of visible light. Aerogels are open porous and can be made out of a wide array of substances such as silica, carbon, carbon nanotubes, metals, and much more (Aerogel.org, NA).
Aerogels are made by first obtaining a gel and purifying it before processing. Due to the chemical reactions within, it leaves behind impurities all through the liquid interior of the gel and obtrude with the drying process. Purification is produced by immersing the gel in a solvent, allowing the impurities to diffuse and the solvent to penetrate. After that, the gel is laid in a pressure vessel below the same liquid held within its pores. The liquids vapor pressure is then raised as the pressure vessel is heats up to the liquid’s critical temperature. This causes the pressure in the vessel to reach the critical temperature of the liquid which is soon. The critical point is then exceeded, changing it into supercritical fluid (Aerogel.org, 2019). With the supercritical fluid spread throughout the entire vessel, the gel’s fluid is be removed. Next, the vessel is gradually depressurised and cooled to room temperature. Meanwhile, the fluid changes into a gas phase, rather than a liquid because most of the liquid has already been removed, and, an aerogel is left behind (Aerogel.org, 2019). Another way to create silica aerogel is to mix tetraethoxysilane – Si(OC2H5)4 with ethanol and water to make it polymerize creating a water based silica gel.
A solvent, such as methanol, is used to extract and replace water. Silica aerogel is the most common type of aerogel. Silica aerogel is made by separating the liquid from the structure of the silica gel in a way that preserves at least 50% of the gels’ framework’s original volume (Aerogel.org, NA). They have a wide array of uses but are mainly used in high-tech science and engineering.
Terraforming Mars has been a dream that a lot of scientists have thought about. However, in 2018, scientists at the University of Colorado considered the question and have concluded that it is not possible with our current technology.
“Our results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming were the gas to be put into the atmosphere; in addition, most of the CO2 gas is not accessible and could not be readily mobilized. As a result, terraforming Mars is not possible using present-day technology,” said Bruce Jakosky, professor at the Laboratory of Atmosphere and Space Physics at University of Colorado, Boulder. (G, 2019)
A study in Nature Astronomy, suggested that Mars could be habitable if we use new technology and only inhabit small parts of the planet, instead of all of it (G, 2019). This regional approach into making Mars habitable is more achievable than making the entire planet habitable.
Researchers have explained how a thin layer of aerogel could make extensive regions of Mars more habitable. In the latest study, researchers have designed an experiment to replicate how UV light passing through an aerogel dome could change the environment below. They have discovered that using a layer of silica aerogel 2 to 3 centimetres thick, transmitted enough UV to pass through for plants to use for photosynthesis whilst also blocking harmful radiation. This would allow the temperature to increase underneath the dome and allow water to flow and plants to bloom. Many researchers have created ‘strong’ silica aerogels by combining silica precursors with polymers, but the it also resulted in a decrease in transparency and has the addition of polymer meaning there is limited use for these aerogels (Vinayak P, 2017). Although this new aerogel has been created, it is still unknown how people will travel through the dome to get in or out.
Aerogels possess characteristics such as low thermal conductivity, modulus, refractive index, dielectric constant, sound speed, high specific surface area and broad adjustable ranges of the density and the refractive index (especially for silica aerogel); low relative density and high porosity (Ai D, 2013). These characteristics displayed, makes it a perfect material to use when on Mars. The extent of these characteristics can be changed my modifying the process that it is made. For example, to change the pore diameter in the aerogel, the reactant concentrations could be changed.
The construction of using aerogel to make Mars habitable was complex and took many hours of research and discussion between all parties involved. The three main researchers, Robin Wordsworth, Laura Kerber and Charles Cockell all had a major impact in the research of using aerogel. The planning of using aerogel consisted of 4 parties; the researchers, the client, the engineer and the space companies. These parties have to be conscious of the amount of money it will take to create this project and if it can be accomplished with today’s technology. Collaboration with Harvard University, U.S., China, Japan and other countries, in addition to a cluster of proposed private company launches to Mars will be vital as well so that it can be transported to Mars.
In conclusion, aerogels are a type of porous solid that can be used to create life on Mars. This substance can be used to create a ‘dome- like’ structure that will keep the CO2 gases in and therefore raising the temperature inside. This theory was researched by Harvard University and researchers from NASA that gave results saying that it is possible but only when inhabiting small areas. The communication and collaboration between different countries meant that the research was possible and was sped up.