The MYCO-NIAC, or the “Mycotecture Off-Planet” project has been advanced by NASA’s Innovative Advanced Concepts (NIAC) program to Phase III. The award is $2 million over two years and allows the development of the concept to a higher “technology readiness level” TRL to be able to grow whole structures off-planet.
In Phases I and II Dr. Lynn Rothschild, astrobiologist at NASA Ames Research Center, and her team developed concepts and prototypes and tested them against simulated space environments. Dr. Rothchild is joined by architect, and mycotect, Chris Maurer who is also developing mycotecture for terrestrial applications as well, Dr. Jim Head III, planetary scientist for many of the Apollo missions, and researchers at Johns Hopkins, Stanford, Brown, McMasters, and Newcastle Universities.
Mycotecture uses fungi to shape the built environment and its benefits to space travel are manifold. Firstly, it is extremely expensive to deliver buildings or building materials to off-planet destinations. Some estimates are as high as $100,000 per pound to the moon and $1,000,000 per pound to Mars. [1]
This has led most space architects and designers to ideate around ISRU, or in situ resource utilization concepts. ISRU is working with the materials you have at destination. Several proposals have looked at 3d printing with regolith (lunar or Martian dirt), compacting regolith into blocks, and even building with ice (water is solid on the Martian surface, but on the moon it would sublimate immediately in the very hot (250F) , long (336 hour) lunar day.)
Figure 1: stills from an animation showing a structure growing on Mars. An inflatable structure is landed and met by rover to supply water and gasses to allow organisms to grow an outer shell. ( https://youtu.be/zsrWd1uJcQg )
Regolith is also challenging as a building medium. Although regolith can be made into very strong materials, strength isn’t what’s required in lunar and Martian environments. The gravity is such on the moon (17% that of Earth) and Mars (38% that of Earth) that bearing strength is not a big deal. The major structural requirement is that materials must withstand the pressure differentials of interior environments (filled with air to breath) and the exterior (no air). This causes an outward force on the structure and consequently, materials with good tensile strength are needed.
Other factors to consider include the huge diurnal (day/night) temperature swings and space radiation. On the Moon we see extremes of 250F in the daytime to -208F at night, and some of the permanently shadowed regions are as cold as -410F. That is very close to absolute zero, where atoms don’t even work anymore.
Regolith and ice are very brittle, are not good in tension, cannot maintain pressure envelopes well, are not good insulators, and while water is an excellent radiation shield when held in place, regolith is not.
Figure 2: Table from Brandic Lipinska et al., comparing ISRU materials. [2]
So, transport is a problem and in situ resources are also problematic. Rothschild and her team developed a middle-of-the-road concept: What if we brought small amounts of living matter and grew that into thousands, maybe millions, of tons of building materials using in situ resources?
How does one grow buildings on the Moon? The short answer is, just add water. The longer answer involves creating a series of lunar optimized bioreactor enclosures (LOBEs) within a well-packed inflatable payload. Rothschild and Maurer met at a biomimicry conference hosted by NASA’s biomimicry group VINE, and Great Lakes Biomimicry and they often turn to biomimicry for solutions. Not only is the building process powered by living organisms, but the architecture is inspired by biology as well. The series of bioreactors that link up are analogous to biological cells, and they are fed by a circulatory system that provides nutrients, gasses, liquids, immunity agents, and maintains thermal management just like our own circulatory systems. The cell walls of the LOBEs include light and heat sources to maintain environments for the microbes to grow; just like mini-spacesuits.
Figure 3: Section through the Myco-NIAC showing the lunar optimized bioreactor enclosures (LOBEs) in the outer perimeter of the inflatable building.
Mycelium needs a nutrient rich substrate, water, and oxygen to grow. The Moon has no atmosphere, but very likely has subsurface water in the permanently shaded regions near the South Pole. If the LOBE’s are pre-packed with a small amount of nutrient-rich hydrogel powder (such as malt extract agar commonly used to make mycological petri dishes) and a small amount of fungal inoculum, the remaining 90-96% of the mass can be sourced in situ by way of water and oxygen derived by water using electrolysis. These hydrogels do double duty. 1) They enable the growth of mycelium that we’ll soon see can be used for radiation shielding, and 2) they can be easily be converted into aerogels which make fantastic insulators.
Aerogels are created in several ways; the easiest amongst them is by freeze drying hydrogels. This is a low-temperature dehydration process that removes water from the frozen gel through sublimation. The sublimated gel is then left with tiny air pockets, which make them extremely light weight. They are also great insulators because as thermal energy (heat) transfers from solid to gas it must convert from conduction to convection, which slows the thermal migration.
The radiation shielding ability of fungi is very interesting. Researchers noticed that dark fungi proliferated near and on the reactors at Chernobyl after the 1986 disaster. When they brought the fungi into their labs to figure out what was happening, they noted that they grew toward radiation sources, making them “radiotropic”. It was further noted that these fungi seem to utilize melanin to shield ionizing radiation and may even transduce the high energy radiation into benign forms of energy like infrared radiation (heat). [3]
The radiation attenuating capabilities of fungi make them extremely invaluable for space travel. Space radiation is a “showstopper” for space explorations and is the main reason we’ve not yet settled on the moon. [4] The danger to our astronauts is too much with current shielding technology. If affective radiation shields are not made for the Artemis missions, astronauts will need to live four to ten feet underground to allow lunar regolith to be the main shield. [5]
The Myco-NIAC team has tested their fungal materials in low earth orbit on the outside of the International Space Station in MISSEs 12 and 13, and have tested their materials at Brookhaven National Laboratory’s BNL simulator of solar wind radiation. In space, there are many kinds of ionizing radiation. Ionizing electromagnetic radiation include Gamma rays, X-Rays, and high power Ultraviolet. Ionizing particle radiation includes galactic cosmic radiation GCR (which are subatomic particles travelling near the speed of light released by far away exploding stars) and coronal mass ejections CME and “solar wind” from our very own sun. From this latter category, proton radiation from the sun represents the biggest problem and the most radiation. A recent test at BNL showed that a myco-composites made by this NIAC team reduced near mission proton radiation dosage of 50cGy from the 50MeV radiation simulator by greater than 99% with just three inches of material – recall that regolith requires four to ten feet. [6] Much more testing needs to be done, but the initial results of the myco-composite materials are extremely promising.
Figure 4: Photo taken from the outside of the International Space Station with myco-composite samples exposed to low earth orbit. Courtesy of NASA, Kim de Groh.
Looking back at our criteria for design: tensile strength, insulation, and radiation protection, we see mycotecture is a great option. The tensile strength is taken up by the inflatable fabrics. Vectran® or Kevlar® inflatable materials have three times the tensile strength of steel. The insulation values of aerogels are greater than any commercially available insulation product, and the radiation shielding effects of the mycelium materials grown with the LOBEs may have shielding abilities of forty time greater than regolith. Add these to the benefit of not needing to disturb the lunar or Martian environments for resource extraction, and you can see why NASA wanted to advance mycotecture technology for space architecture.
Figure 5: Illustration of grown structure on Mars. The building’s fenestration is part of the bioreactor system allow light to pass through, but utilizing water and living organisms as shields for ionizing radiation.
Contributing Author: Christopher Maurer
Christopher Maurer is an architect and inventor of bioterial technologies. Chris has developed new architecture and manufacturing processes for NASA, MIT and other major research institutions. He has designed and built all over the world and is committed to furthering regenerative architecture to help humanity and ecosystems recover from current modes of building and production.
References
[2] Brandić Lipińska Monika, Maurer Chris, Cadogan Dave, Head James, Dade-Robertson Martyn, Paulino-Lima Ivan Glaucio, Liu Chen, Morrow Ruth, Senesky Debbie G., Theodoridou Magdalini, Rheinstädter Maikel C., Zhang Meng, Rothschild Lynn J., Biological growth as an alternative approach to on and off-Earth construction, Frontiers in Built Environment, VOLUME 8, 2022, , DOI 10.3389/fbuil.2022.965145
[3] Dadachova E, Bryan RA, Huang X, Moadel T, Schweitzer AD, Aisen P, Nosanchuk JD, Casadevall A. Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi. PLoS One. 2007 May 23;2(5):e457. doi: 10.1371/journal.pone.0000457. PMID: 17520016; PMCID: PMC1866175.
[4] https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/ The_radiation_showstopper_for_Mars_exploration
[5] Graham K. Shunk, Xavier R. Gomez, Christoph Kern, Nils J. H. Averesch. Growth of the Radiotrophic Fungus Cladosporium sphaerospermum aboard the International Space Station and Effects of Ionizing Radiation. bioRxiv 2020.07.16.205534; doi: https://doi.org/10.1101/2020.07.16.205534
[6] Testing at Brookhaven National Laboratory, Simplified Galactic Cosmic Radiation Simulator SimGCRSim https://www.bnl.gov/nsrl/userguide/simgcrsim.php
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