High-Level Project Summary
HMG (Hydroponics Microgravity Greenhouse) is a hydroponic crop production system that works in microgravity environment or in the surface of Mars and the Moon. Its purpose is provide fresh green food in the space for a crew of astronauts during a long-term mission to Mars. The system operates autonomously, with reduced power and water, which will be reused. Also, is lightweight and easy to handle, not requiring much stowage space.
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Detailed Project Description
PROBLEM
A lack of vitamin C was all it took to give sailors scurvy, and vitamin deficiencies can cause a number of other health problems. When crews venture further into space, traveling for months or years without resupply shipments, the vitamins in prepackaged form break down over time, which presents a problem for astronaut health. They will need fresh food.
SOLUTION
Important Information
Source of light: Growing plants in space seems to be difficult, because of the absence of gravity and solar light. A system able to provide high quality fresh food in space needs to use artificial light, like banks of light emitting diodes (LED), to produce a suitable spectrum of light for the plants' growth. LEDs colors could include red, green, and blue, but also white, far red and even infrared to allow for nighttime imaging.
Autonomy of the system: The crop system also needs to operate with low consumption of water and power. Its water recovery and distribution, atmosphere content, moisture levels and temperature must all be automated. According to the required necessities, the system itself must provide the needed resources.
Capillary flow: In a microgravity environment, surface tension changes the fluids dynamic behaviour. Instead of gravity force, the fluids will flow by capillary force. Using capillary tubes, it is possible to water flow from a reservoir to the plants.
Radiation Shielding: Operating within the deep-space radiation environment and exposure to high energy Galactic Cosmic Radiation (GCR) and Solar Particle Events (SPE) could bring serious damage to plants. It is desirable that the system incorporate some radiation shield to protect the crops. Potencial materials that could be used in this radiation shield are kevlar and polyethylene.
Solution concept
As the system need to operate with reduced consumption of water, it was suitable the development of a hydroponics greenhouse, that will reuse water as a closed system.
The greenhouse was named HMG (Hydroponics Microgravity Greenhouse), and should be able to operate in a microgravity environment or in the surface of Mars or the Moon.
HMG may contain sensors to measure data, as temperature, water distribution, moisture, oxygen and carbon dioxide levels.
Design of a 3D model
The greenhouse is basically a lightweight box that could be incoporated in a vehicle or a habitat in the surface of Mars or the Moon. The 3D model for the solution was developed using Tinkercad (an online tool to build CAD projects).
A bank of light emitting diodes (LED) produces a spectrum of light suited for the plants’ growth. Plants reflect a lot of green light and use more red and blue wavelengths, so the LED bank should glow magenta pink (composition of red and blue).
Plants grow inside cells on a plastic base. Plant roots obtain nutrients from water stored in the cells. In this concept, two fans on the side wall control the system's temperature.
Water supply is stored in a reservoir at the back of the greenhouse. Through capillary force, water goes from the reservoir to the plant cells by tubes, providing needed nutrients for the plants' growth. All the water will be reused to restart the cycle.
Relevant ideas
Sanitation is important to keep food clean and suitable to consume by humans. Food-safe citric acid-based wipes (the solution used in NASA's Veggie system) could be used to sanitize the fresh produce.
When deployed in a habitat on the surface of Mars, the HMG could use the in-situ regolith of the red planet to grow plants on dirt, alongside hydroponics.
Since the system use a reduced supply of water, it could be deployed not only on space, but also in arid regions on Earth.
Beyond the nutritional benefits brought by the HMG, the action of caring for plants brings psychological benefits for astronauts during a long time mission.
Space Agency Data
NASA. 2021. Growing Plants in Space. [online] Available at: <https://www.nasa.gov/content/growing-plants-in-space/> [Accessed 3 October 2021].
NASA. 2021. Advanced Plant Habitat. [online] Available at: <https://www.nasa.gov/sites/default/files/atoms/files/advanced-plant-habitat.pdf> [Accessed 3 October 2021].
NASA. 2021. Veggie Facts Sheet. [online] Available at <https://www.nasa.gov/sites/default/files/atoms/files/veggie_fact_sheet_508.pdf> [Accessed 3 October 2021].
Hackathon Journey
Our team have multidisciplinary people that brought different skills to contribute in the development process of the solution. We got involved in NASA research and resources that helped to understand the problem, mining many ideas that could be useful and discussing the validity of each idea. It was possible learn many things that were related to the challenge. We want to thank Space Apps Challenges Salvador organization team and the mentors for the amazing work done during the event, awesome communication and the interesting content shared that helped to build important knowledge for everyone involved.
References
Narici, L., Casolino, M., Di Fino, L. et al. Performances of Kevlar and Polyethylene as radiation shielding on-board the International Space Station in high latitude radiation environment. Sci Rep 7, 1644 (2017). https://doi.org/10.1038/s41598-017-01707-2
Irons, MA. The Development of Regolith as a Resource for Establishing Quasi-Closed, Agro-Ecological Systems in our Solar System. AAPG ACE 2018.
Tags
#engineering #food #mars #moon
Global Judging
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