STAR

https://www.youtube.com/watch?v=AwJaAUGzYL0

https://drive.google.com/drive/folders/1RPe4M3X36a7qphkOe_zr7Lor9BvYqTYF?usp=sharing

Introduction

This project is aiming to design a lightweight honeycomb shaped greenhouse that would nutritiously sustain astronauts with a plant-based diet. It would do so by providing a foldable and modular greenhouse that grows plants between two thin Kevlar fabric walls in an aeroponic feeding environment. The water and gases are to be recycled along with the vapours that will be cooled and reintroduced in the water tank and reused. A waste management system will also recover water out of the plant residue left behind after harvesting, thus dramatically increasing the level of sustainabilityas roughly all elements are being recycled. Water enriched with nutrients will provide the chemical nourishment for the plants, therefore reducing the mass of material needed for plant growth. The system will be controlled by an artificial intelligence robot that will record the parameters of the greenhouse and manage it into the most efficient plant growth conditions, therefore decreasing human interface in the process. The greenhouse is particularly designed to use as little mass and weight as possible in order make it feasible for interplanetary travel and to provide a flexible production rate of vegetables. 

Main body 

Greenhouse design and logistics.

The chamber kit is primarily stored in the ship during the launch and initial phase of the mission, in a very compact manner (as its walls are thin and they are pliant onto each other, thus occupying little space when not in use). When assembled, it forms a hexagonally-shaped prism in order to maximize the surface area and avoid narrow angles, where plants would not have enough light and space to grow. The shapes are modular, extra columns can be attached to the basic model in order to make it longer and the structure itself can be attached to another structure in order to form a comb structure to save space. 

The greenhouse is sealed by the two lids at the end of its cylindrical shape thus making it a closed system. Should the atmospheric conditions be right the top lid could be at least partially removed in order to allow for direct airflow and exchange of gases between the plants and the cabin to take place. This reduces the levels of electricity needed to sustain the greenhouse by shutting down the heat management system and the ventilation system but would also leave the crop exposed (should a sudden change in conditions occur).

 Given the fact that the materials, mechanical systems and nutritional resources required to grow the plants are to be flown out of earth’s gravity, it is crucial that the overall system is as light and compact as possible. In order to meet that requirement, the plants will be fed via an aeroponic system compared to a traditional, soil-based organic system that would be a lot heavier and occupy more space. Watering of the plants will be accomplished using a double-walled structure, the interior of which will contain only the roots and will be subjected to periodical water-air spraying, using 120-degree nozzles. Furthermore, the water and gases will be recycled in order to ensure the effective functionality of the project in a resource efficient approach.  

Aiding the weight and space/volume problem, walls will be built from thin, high-quality air and water -impermeable material (e.g., Kevlar, RXF1 or hydrogenated boron nitride nanotube-based fabrics, coated with siloxane or vinyl chloride polymers), that would also permit it to easily fold, but also have a high stress resistance. It will have both prefabricated nozzles for water and air circulationary systems and plant sowing slit sots. One of the tube ends will present the sensors needed for the plant growth and between the two lids a coiled LED neon strip attached to a telescopic supportive rod cable will be attached in order to deliver light to the plants in form of photosynthetically active radiation (PAR), covering either a full spectrum that best imitates sunlight (e.g. Sunlight LED AP(Apollo)-2835, 5600 K) or a more practical red | blue ratio that can be modified according to the plant’s needs. The photosynthetic photon flux density should vary around 500 μMol/m2/s (and can be increased to over 1000 μMol/m2/s, to better simulate sunlight), greatly depending on the biomass volume, chosen species, available ship energy and plant growth stage.

Not having the earth’s magnetic field to block radiation (solar particle events and galactic cosmic radiation) could damage the plants, especially in the early stages of plantlet and most importantly rootlet development, since cell division is at its highest. if they are directly exposed to the sun rays, therefore a Kevlar or similar radiation-shielding fabric would be provided in the exterior wall of the greenhouse for UV protection.  

The greenhouse chambers shape is designed to be able to accommodate multiple shapes next to one another thus forming a comb-like structure that would be space efficient and would additionally facilitate the independent greenhouse water and ventilation system to be interconnected via the same pressurised tube system. 

Reliable materials are to be used in order to avoid any malfunction or spare parts that would occupy additional space, but the greenhouse should be close to fail-proof by design, using a minimal number of complex or frail components (valves, nozzles, fans), and mostly tear-resistant, flexible, waterproof materials for the tubulation.     

 In order to minimise the usage of chemical nutrients, the nutrient-enriched water will be enclosed in a cycle and reused throughout the inner pocket of the double walls. In this regard a system will be installed in order to recapture water vapours, to cool them (if needed), and reintroduce them in the water tank. A pump will be fitted in order to run both the air and water cycles in the inner wall membrane pocket; also, and a simple fan is used to ventilate the air within the growing chamber. The pump presents three exit pressure valves that would be parallelly linked to the air and water systems. It will first drive water to the roots of the plants through a network of thin tubes and pulverize it at a desired angle, using nozzles. The second valve will be pressurized in order to drive any excess water off the roots to allow air access to the rhizosphere of the plant to breathe. Finally, the third pressure valve will ensure the circulation of the air inside the growing chamber out, and through specialized filters in order to deplete the air of moisture that will subsequently be reintroduced in the chamber after being calibrated on the right concentration of gases, (some oxygen might have to be taken out and some carbon dioxide might have to be introduced).

The structure of the greenhouse is designed to resist the gravity of Earth and can also withstand no gravity and the partial gravity of Mars, as the walls themselves will be quite lightweight, the inner pocket does not hold any solid substrate for the roots, and FLiGHT is designed mainly for plants that reside in the “microgreens” class. The irrigation and air circulation systems are also fitted to perform in zero gravity conditions but would also do well on the surface of each of the two planets therefore the production requirements can be met wherever it is required. Given the space that the greenhouse needs to be shipped and the flexibility in size it provides via its modular function, plant growth can be ramped up or reduced according to the needs of the crew. Thanks to the comb-structure more hexagons can be added next to the existing ones according to the available space, thus ramping production even further if needed. 

Greenhouse mechanism 

Given the fact that the nutrients, water and air delivery system is run by an A.I. in an enclosed controlled environment, crew interaction should be at the minimum. They would only have to commence weekly supervision of the greenhouses, assemble the greenhouses and plug the installations. Place the pre-planted seed wicks in the wall slits and refill the water tank. All decisions regarding the gas exchange concentrations, quantity of water in the system, temperature and humidity will be made by the A.I. in concordance with the growth stage of the plants and the species type of breed that is currently growing. The A.I. will receive feedback from the sensors fitted inside the greenhouse and take decisions accordingly, adapting to the conditions in real time. 

Plant growth

The seeds will be glued between two layers of porous textile strips (e.g. cellulose), by use of a very small amount of mucilaginous macromolecule or gum (guar, acacia), that readily expands when exposed to water. The seed is strategically oriented considering the asymmetrical placement of the embryo beneath the endosperm (thus, further facilitating the correct growth of the plantlet’s aerial organs). This whole arrangement, known as a “wick”, will serve both as a safe seed carrier, practical solution to orient the plant and as a capillary-absorptive material to accommodate the early rootlets.

Considering the fact that an artificial intelligence integrated system robot will be controlling the parameters of the growing plants, temperature, humidity, light intensity and photoperiod, CO2, O2, ethylene, air flux control are all features that will be accounted for. Control is crucial to the growth of the plants themselves, therefore a temperature managing system will also be installed.  

Broadly speaking, the temperature should range between 20-30 degrees Celsius, and in the inner pocket, the CO2 levels should be less than 1%, while O2 levels must always be greater than 10%. Also, every species has its own “light recipe” needs.

The greenhouse chambers shape is designed to be able to accommodate multiple blocks next to one another thus forming a comb-like structure that would be space efficient and would additionally facilitate the independent greenhouse water and ventilation system to be interconnected via the same pressurised tube system. 

Given the fact that there is no gravity in space and the humidity and gases eliminated by the leaf plants could potentially harm both the plant itself or the ship equipment, the greenhouse chamber of the plants must be very well-ventilated in a closed environment and is to be opened only when conducting maintenance or collecting the harvest.  

 Recycling and sustainability

 In order to make use of all the water an appropriate waste management system will be put in place. This will work so by collecting the plant and wick residue from within the greenhouse after the harvest has been completed and then burn them in an anaerobic small-scale combustion oven, given that electrical energy is not a constraint, an oven at 1200 degrees Celsius in order to recollect the water via vapours that are subsequently cooled down and reintroduced in the water tank. 

All the systems provided to the greenhouse would allow it to thrive even in the most arid regions here on earth, or in events of catastrophise and do so with minimal resource consumption. Given enough water, electricity and the organic chemical materials the greenhouse could maintain a constant controlled environment, ideal for plant growth.

In Addition to the recycling mode a further water depletion mode will be available. Should the greenhouse no longer be needed, most of the water and oxygen could still be used as raw materials for the survival of the astronauts. The pump will cycle air through all the tubes driving out the moisture via liquid water or vapours until the greenhouse is fully dehydrated. 

Greenhouse secondary benefits

 A further benefit of the Growing crops in our proposed greenhouses, during the trip to Mars, would be more psychologically inclined, regarding the well-being and the sense of accomplishment that space farming, growing plants would provide to an astronaut. To accommodate the crew with a view of the on plants, one of the lids could presents a retractable transparent membrane. The interior of the comb walls will also be coated with a highly light-reflective paint, as to ensure minimal PAR wasting.

To help balance the concentration of gases in the tanks an exchange of oxygen should be made with the exterior environment in exchange for carbon dioxide. Plants are mainly converting carbon dioxide into oxygen in order to perform photosynthesis. This process would require a large amount of carbon dioxide to sustain them throughout the journey which in turn requires a large space. Due to most processes occurring in the ship carbon dioxide is an common resulting gas and will be available in abundance from processes like human respiration., therefore a carbon dioxide tank is no longer needed as it can be acquired from the ship environment. The gas exchange between the greenhouse and ship environment would benefit both parties as they expire the gases that each other need in order to survive and perform breathing and respectively photosynthesis.

Food for thought (future concepts):

1. Biotech involvement in genetically-engineered plants (drought-resistant, heat-resistant, pathogen-resistant, high-yielding, biofortified crops)
2. Broader use of plants to include nutraceuticals and especially medicinal plants (e.g. Hypericum perforatum L., Nigella sativa L., Salvia hispanica L., Centella asiatica (L.) Urb., Ocimum sp., Thymus sp., Lavandula sp.) that could act as cognitive enhancers, antidepressants, sedatives, immunomodulators.
3. Aquaponic cultures of hydrophytes (Cyperus esculentus L., Pistia sp.) or further aeroponic endeavours regarding plants with aerophyte or epiphyte behaviour.
4. Nutritional value and use of plants with edible flowers. 
5. Growing of higher fungi in space!
6. Mycorrhizae and/or Rhizobium sp symbiosis with different species of plants.

Conclusion 

Considering the efficiency of the project design and its ability to be deployable at any time while occupying little space in standby we consider that our project brings a sheer amount of innovation that is applicable in a manned missions to mars primarily but also in arid places on earth. Bringing together the aeroponic feeding system and the closed circuit of water and nutrients in the system will surely improve the production rate of veggies with fewer resources. 

All things considered there are still plenty of engineering questions to be answered and some design features to be improved. 

ESA - Greenhouse in Space: Food in Space lesson (Part 1)

Tomatosphere - Tomatosphère | Light & Plants (letstalkscience.ca)

Tomatosphere - Tomatosphère | Seeds and Germination (letstalkscience.ca)

ESA - ESA Euronews: Growing food in space

Growing healthy food in space and in remote areas | Canadian Space Agency (asc-csa.gc.ca)

Naurvik project in Nunavut | Canadian Space Agency (asc-csa.gc.ca)

advanced-plant-habitat.pdf (nasa.gov)

Veggie Fact Sheet (nasa.gov)

Plant Habitat-04 | NASA

Veg-03 Plant Pillows Readied at Kennedy Space Center for Trip to Space Station – Kennedy Space Center (nasa.gov)

APEX-08 (nasa.gov)

NASA Tests Ways to Reduce Stress in Plants Growing in Space | NASA

NASA Prepares for Deep Space Exploration by Growing Tomato Plants from Irradiated Seeds – Kennedy Space Center

Consulting the available data, we were immediately mesmerized by the sheer volume of quality research on space farming! It inspired interdisciplinarity first of all - astronauts, plant scientists, space engineers, agronomy/horticulture experts, all bringing fresh and valuable ideas towards humanity’s next giant leap, the one mission to Mars. That was what we tried to imitate in our team - people from various scientific backgrounds working towards a united goal. Right off the bat, we extracted the most important aspects that seemed to continually re-emerge from every experiment: these were the need of an intelligent and extremely efficient use of space, lightweight materials, economical use of both water and nutrients, photosynthetically and energy-efficient light sources, controlled greenhouse environment, potential radiation shielding. This inspired a foldable and modular design, and the hexagonal form (biomimicry!), but also the integration of aeroponics.

How it felt to work as a team:

Working together on a project we all had passion for was very enjoyable. We got to know each other better by overcoming challenges together. It felt like everyone in the team knew their task and each of us was able to bring their own value to the project. The fact that we had different skills came in handy as various tasks had to be carried out. It was very helpful that we were able to communicate openly and that we had similar ages and orientations in life which brought us closer together as individuals. Besides the project, we built trust in each other that enabled us to rely on one another for help, by being fully confident in each other's abilities.

Wheeler, R. M. (2017). Agriculture for space: people and places paving the way. Open agriculture, 2(1), 14-32.

Carillo, P., Morrone, B., Fusco, G. M., De Pascale, S., & Rouphael, Y. (2020). Challenges for a sustainable food production system on board of the international space station: A technical review. Agronomy, 10(5), 687.

Izzo, L. G., Romano, L. E., De Pascale, S., Mele, G., Gargiulo, L., & Aronne, G. (2019). Chemotropic vs hydrotropic stimuli for root growth orientation in microgravity. Frontiers in plant science, 10, 1547.

Kyriacou, M. C., De Pascale, S., Kyratzis, A., & Rouphael, Y. (2017). Microgreens as a component of space life support systems: A cornucopia of functional food. Frontiers in plant science, 8, 1587.

Seedhouse, E. (2020). Life Support Systems for Humans in Space. Springer Nature.

Kitaya, Y. (2019). Plant Factory and Space Development,“Space Farm”. In Plant Factory Using Artificial Light (pp. 363-379). Elsevier.

Vermeulen, A. C., Hubers, C., de Vries, L., & Brazier, F. (2020). What horticulture and space exploration can learn from each other: The Mission to Mars initiative in the Netherlands. Acta Astronautica, 177, 421-424.

De Pascale, S., Arena, C., Aronne, G., De Micco, V., Pannico, A., Paradiso, R., & Rouphael, Y. (2021). Biology and crop production in Space environments: challenges and opportunities. Life Sciences in Space Research.

Berkovich, Y. A., Konovalova, I. O., Smolyanina, S. O., Erokhin, A. N., Avercheva, O. V., Bassarskaya, E. M., ... & Tarakanov, I. G. (2017). LED crop illumination inside space greenhouses. Reach, 6, 11-24.

Younis, A., Siddique, M. I., Kim, C. K., & Lim, K. B. (2014). RNA interference (RNAi) induced gene silencing: a promising approach of hi-tech plant breeding. International journal of biological sciences, 10(10), 1150.

García-Bañuelos, M. L., Sida-Arreola, J. P., & Sánchez, E. (2014). Biofortification-promising approach to increasing the content of iron and zinc in staple food crops. Journal of Elementology, 19(3).

De Visser, C. H. R. I. S. (2013). Protein Crops.

Oluwafemi, F. A., De La Torre, A., Afolayan, E. M., Olalekan-Ajayi, B. M., Dhital, B., Mora-Almanza, J. G., ... & Rivolta, A. (2018). Space food and nutrition in a long term manned mission. Advances in Astronautics Science and Technology, 1(1), 1-21.

Fotev, Y. V., Artemyeva, A. M., & Zvereva, O. A. (2021). Genetic resources of vegetable crops: from breeding non-traditional crops to functional food. ВАВИЛОВСКИЙ ЖУРНАЛ ГЕНЕТИКИ И СЕЛЕКЦИИ, 442.

Menz, J., Modrzejewski, D., Hartung, F., Wilhelm, R., & Sprink, T. (2020). Genome edited crops touch the market: a view on the global development and regulatory environment. Frontiers in plant science, 11.

Wheeler, R. M. (2016). Growing Plants for Supplemental Food Production on a Mars Fly-By Mission. Earth, 3, 11.

Corręa, R. C. G., Garcia, J. A. A., Correa, V. G., Vieira, T. F., Bracht, A., & Peralta, R. M. (2019). Pigments and vitamins from plants as functional ingredients: Current trends and perspectives. In Advances in food and nutrition research (Vol. 90, pp. 259-303). Academic Press.

Moroz, A., Cheremisin, A., Meshalkin, V., Zhuchenko, A., Kosolapov, V., Semenova, N., & Davydov, V. (2020, October). On the possibility of growing vegetables and fruits on the lunar base. In IOP Conference Series: Earth and Environmental Science (Vol. 578, No. 1, p. 012006). IOP Publishing.

Nechitailo, G. S., Bogoslovskaya, O., Glushchenko, N., & Olkhovskaya, I. (2018). Creation of Nutrient Medium Using Nanotechnoloigy for Plants Growing in Spaceflights. 42nd COSPAR Scientific Assembly, 42, F4-4.

Monje, O. (2017, June). Space Farming: Challenges and Opportunities. In Institute of Food Technologies (IFT) 2017.

Medina, F. J. (2021). Space explorers need to be space farmers: What we know and what we need to know about plant growth in space.

Monje, O., Dreschel, T., Nugent, M., Hummerick, M., Spencer, L., Romeyn, M., ... & Fritsche, R. (2019, July). New Frontiers in Food Production Beyond LEG. 49th International Conference on Environmental Systems.

Haveman, N. J., Khodadad, C. L., Dixit, A. R., Louyakis, A. S., Massa, G. D., Venkateswaran, K., & Foster, J. S. (2021). Evaluating the lettuce metatranscriptome with MinION sequencing for future spaceflight food production applications. npj Microgravity, 7(1), 1-11.

Massa, G. D., Dufour, N. F., Carver, J. A., Hummerick, M. E., Wheeler, R. M., Morrow, R. C., & Smith, T. M. (2017). VEG-01: Veggie hardware validation testing on the International Space Station. Open Agriculture, 2(1), 33-41.

Khodadad, C. L., Hummerick, M. E., Spencer, L. E., Dixit, A. R., Richards, J. T., Romeyn, M. W., ... & Massa, G. D. (2020). Microbiological and nutritional analysis of lettuce crops grown on the international space station. Frontiers in plant science, 11, 199.

Rop, O., Mlcek, J., Jurikova, T., Neugebauerova, J., & Vabkova, J. (2012). Edible flowers—a new promising source of mineral elements in human nutrition. Molecules, 17(6), 6672-6683.

#foldable #combstructure #spaceefficient #greenhouse #hexitube #light #veggies #artificialintelligence # autonomoussystem #wastemanagement #efficientproduction #closedenvironment #environmentcontrol #microgravity #partialgravity #radiationshield #design

This project has been submitted for consideration during the Judging process.