Growing fungi structures in space
The additive manufacturing technology is very promising technique for utilising in situ resources on the Moon and Mars. However, when using the indigenous resources, it is also important to consider the investments needed for (a) prospecting to locate and validate the accessibility of indigenous resources and (b) developing and demonstrating capabilities to extract indigenous resources, (c) developing capabilities for processing indigenous resources to convert them to needed products, and (d) any ancillary requirements specifically dictated by use of ISRU . In that case, fungi based biocomposites might offer a cost effective alternative for constructing structures in situ. In situ manufacturing of fungi structures would require bringing seeds of specific fungi to space which then would grow into composite structures in situ. However, only a minimum amount of seeds should be brought from the Earth for the pilot structure as the seeds for the following projects would be produced in situ. The production of fungi structures could be low cost and could require only limited human assistance, eliminating therefore costly and time consuming locating, validating and extracting processes of local resources .
Fungi based biocomposites are produced by combining fungal mycelium with a natural reinforcement or filler. These materials are renewable and recyclable, and are slowly starting to replace various plastics, packaging and insulating materials on Earth. The fungi based biocomposite is also being discovered by artist, designers and architects who have been successful in using these materials in many new ways . Bricks and new architectural structures have been produced with fungi , as well as various fungi based products [5,6,7]. The combination of 3D printing with living organisms has been studied using 3D printing technique with organic waste, which then formed the basis for the mycelium growth. The mycelium grew through the organic waste, forming a network of interwoven roots, which then bound the material into cohesive and strong biocomposite structure .
From a large group of fungi, Ascomycota and Basidiomycota are known to be the best type of fungi to create mycelium based materials as they can construct larger and more complex organic structures than other fungi . From the two, Basidiomycota have two important properties which can make them more suitable for producing biocomposites: Septa and Anastomosis. Septa, special transverse cell walls, have an opening that can be closed in order to block the draining of a cytoplasma through the rapture when hypha becomes damaged. This will decrease the damage of the colony and therefore will lead to faster colonization of a substrate. Also anastomosis increases the growth speed of mycelium by fusing two different hyphae together when they meet. In addition, it creates a more homogeneous network of mycelium which promotes a fast transport of nutrients.
It is possible to create suitable growing conditions for fungi regarding temperature, humidity and atmosphere in a space environment. An important question, however, is whether fungi are able to survive in environments with a high radiation level. Due to weak or inexistent magnetic field, the Moon and Mars are exposed to galactic cosmic radiation (GCR), solar winds and solar particle events (SPEs). There is, however, evidence that a specific type of fungi can survive the simulated Martian conditions [10,11] and that the ionizing radiation can even enhance the growth of melanised black fungi [12,13,14]. Onofri, de Vera, Zucconi, et al proved in their Lichens and Fungi Experiment (LIFE) that Cryomyces antarcticus and Cryomyces minteri are able to survive the simulated martian conditions aboard the Internatinal Space Station for 18 months. They found that more than 60% of the cells and rock communities did not undergo any change due to the exposure . Dadachova, Bryan, Huang, et al studied melanised microorganisms, such as Cryptococcus neoformans, Wangiella dermatitidis and Cladosporium sphaerospermum and found that ionizing radiation changes the electronic properties of the organisms and enhances their growth . In another study, researchers were able to provide clues how melanised black yeast Wangiella dermatitidis has adapted the ability to survive or even benefit from exposure to ionizing radiation . These studies suggest that melanin pigments play a crucial role in the survival of fungi when exposed to radiation, which could mean that it is necessary to choose, either melanin containing fungal species when developing the architectural structures for space environment, or add melanin pigments to the species which does not contain them yet.
Fungi based biomaterials could offer the following advantages over other in situ manufacturing technologies:
- Costs: Lower manufacturing and energy costs due to excluding the costs of (a) prospecting to locate and validate the accessibility of indigenous resources, (b) developing and demonstrating capabilities to extract indigenous resources and (c) developing capabilities for processing indigenous resources to convert them to needed products
- Manufacturing: Full manufacturing loop following a cradle-to-cradle principle: the waste of another process (e.g. greenhouse) can be used as a basis for building structures, which at the end of their service period can be used biodegraded
- Mass: Light weigh, therefore easy to handle. Can be used for complex shapes
- Known to hold compressive and tension stresses. Non-flammable, waterproof, good insulation properties.
- Strength: Forms a fibrous composite with a substrate, which enhances the material strength. Can be used for complex shapes
- Diversity of applications and products: Enables to produce a variety of different fungi based materials: from transparent films to concrete/ brick like materials
- Speed: Grows relatively fast (in general two weeks)
References Rapp, D., 2008. Human Mission to Mars. Enabling Technologies for Exploring the Red Planet. Springer
 Howe, A.S., Wilcox, B., McQuin, C., Townsend, J., Rieber, R., Barmatz, M., Leichty, J., 2013. Faxing Structures to the Moon: Freeform Additive Construction System (FACS). AIAA SPACE 2013 Conference and Exposition, September 10-12, 2013, San Diego, CA
 Officina Corpuscoli: 10. http://www.corpuscoli.com/
 MycoWorks: http://www.mycoworks.com/portfolio/mycotecture/
 Ecovative Design: http://www.ecovativedesign.com/
 Saporta, S., Yang, F., Clark, M., 2015. Design and Delivery of Structural Material Innovations. Structures Congress 2015, p. 1253-1265
 The Living New York: http://thelivingnewyork.com/hy-fi.htm
 Eric Klarenbeek: http://www.ericklarenbeek.com/
 Lelivelt, R.J.J., 2015. The mechanical possibilities of mycelium materials. Eindhoven Univeristy of Technology
 Scalzi, G., Selbmann, L., Zucconi, L., Rabbow, E., Horneck, G., Albertano, P., Onofri, S., 2012. LIFE Experiment: Isolation of Cryptoendolithic Organisms from Antarctic Colonized Sandstone Exposed to Space and Simulated Mars Conditions on the International Space Station. Origins of Life and Evolution of Biospheres 42, p. 253-262
 Onofri, S., Vera, J.-P., de, Zucconi, L., Selbmann, L., Scalzi, G., Venkateswaran, K.J., Rabbow, E., Torre, R., de la, Horneck, G., 2015. Survival of Antarctic Cryptoendolithic Fungi in Simulated Martian Conditions On Board the International Space Station. Astrobiology 15 (12), p. 1052-1059
 Zhdanova, N.N., Tugay, T., Dighton, J., Zheltonozhsky, V., Mcdermott, P., 2004. Ionizing radiation attracts soil fungi. Mycological Research 108 (9), p. 1089–1096
 Dadachova, E., Bryan, R.A., Huang, X., Moadel, T., Schweitzer, A.D., Aisen, P., Nosanchuk, J.D., Casadevall, A., 2007. Ionizing Radiation Changes the Electronic Properties of Melanin and Enhances the Growth of Melanized Fungi. Plos One (5), e457
 Robertson, K.L., Mostaghim, A., Cuomo, C.A., Soto, C.M., Lebedev, N., Bailey, R.F., Wang, Z., 2012. Adaptation of the Black Yeast Wangiella dermatitidis to Ionizing Radiation: Molecular and Cellular Mechanisms. Plos One 7 (11), e48674