“It always seems impossible until it is done” - Nelson Mandela.

As a project revolving around Mars and creating habitable areas, we knew that testing our material at Earth conditions wouldn’t suffice. The gravity is not the same and humans cannot breathe in the low pressure of Mars atmosphere, so the pressure inside the buildings needs to be higher than the atmosphere. This leads to a pressure gradient resulting in stress on the material. Using COMSOL we have simulated these conditions on our final structure using COMSOL, with material properties measured by ourselves. Secondly, the radiation hitting earth is deflected by the magnetic field and absorbed by the atmosphere, neither of these are very strong on Mars. This could potentially limit the growth, this we have also tested[LINK TO MATHIAS’ RADIATION].

1.

Firstly, not many have made building materials from Aspergillus, so we made tests of the material properties of our own bricks. These tests were based on the statistical design of experiments. We then used this data and COMSOL to simulate the stresses on our structure on Mars. These simulations showed that based on our materials we would need a wall thickness a little over 0.3 m.

Secondly, the radiation levels on Mars are higher, since there’s no protective magnetosphere (1). This means that when the bricks are grown, they will have to withstand a constant level of increased radiation, compared to Earth. Growth experiments were conducted, testing the effects of the increased amounts of $\gamma$-radiation, since $\beta$-radiation and $\alpha$-radiation are fairly easy to block. It was found that the fungus was still able to grow under a level of $\gamma$-radiation [LINK TO RADIATION GROWTH], which is comparable to that on the surface of Mars. Controls were prepared, but it is thought that the temperature of the irradiated samples was higher than 20° Celsius, since the controls had grown less than the irradiated samples.

2.

Now that we had faith in our structure based on physics, we could turn our attention to our actual material. Fungus, with their immense biodiversity, holds a wide range of growth conditions that are all affected differently. Unfortunately, our early experiments mostly illustrate that A. oryzae grows at a slower rate, at colder exposure (it showed no growth in the refrigerator over multiple days; we refer to our notebook for further details). We hypothesize that by implementing the choline dehydrogenase and/or betaine aldehyde dehydrogenase from Psychromonas ingrahamii, as was demonstrated by the Stanford-Brown team in 2012 (2), we could surpass this issue.

Due to various phenotypic signals, color changes in the amilCP constructs and MelA constructs, we are optimistic that our system will work on site.

As our project isn’t necessarily a solution attractive to the general population as most people do not spend their time on considering Mars habitation, we found it difficult to engage with them and troubleshoot our solution outside the circle of specialists. Through our work in human practices we were able to hear opinions from a wide range of audiences and learn that the topic revolving our project is becoming a more common discussion subject. The biggest issue regarding our project lied with the use of GMO which around 60% of Denmark do not want (3). It is GMO in food that people holds a negative attitude against and as this isn’t our goal, we were able to positively influence most opinions.

Our solution compelled to a high percentage and it seemed our solution is encouraged by a meaningful size of the population for a future Mars habitation advancements.

(1) Matt W. How Bad is the Radiation on Mars? Universe Today. 2016. https://www.universetoday.com/14979/mars-radiation1/. Accessed October 15, 2018.

(2) iGEM Stanford-Brown. Hell Cell - cold. 2012. https://2012.igem.org/Team:Stanford-Brown/HellCell/Cold. Accessed October 15, 2018.

(3)Hansen PB. Danskerne vil ikke spise GMO. Altinget. 2010. https://www.altinget.dk/foedevarer/artikel/2010-5-10-danskerne-vil-ikke-spise-gmo. Accessed October 15, 2018.