Hydroponic System Simulation of UVC Effects on Plant Growth for Mars

OneJae Lee – Maui High School

     Mars is currently being researched for future expeditions and even colonization efforts. National Aeronautics and Space Administration (NASA) is currently looking into the viability of food production and ways of maximizing efficiency food production on Mars for long expeditions. An important fact to remember when dealing with farming crops on Mars is the environment. Mars has a very thin atmosphere, about 100 times thinner than that of Earth Mars also lacks a global magnetic field. Due to this, more harmful radiation like ionizing radiation, galactic cosmic rays and high-energy ultraviolet rays contact the surface of Mars. Recent data shows that the surface radiation from galactic cosmic rays is equivalent to 0.67 millisieverts per day These high-energy rays are known to cause DNA damage, tissue damage, and even death in living organisms. The higher exposure to high-energy rays on Mars brings up a question of whether or not the light present on Mars is suitable for plant growth. If growth rate, final mass and also qualitative data between a control hydroponics system only being exposed to normal visible light to an experimental hydroponics system exposed to both normal visible light as well as high energy radiation were compared, then the effects of the high-energy radiation present on Mars on plants could be approximated. Although it would be very difficult to replicate galactic cosmic rays in a laboratory setting due to it being impossible to create a supernova in such settings, it is possible to test other types of high energy radiation. One type of radiation that is found in higher amounts on Mars compared to Earth is ultraviolet-C (UVC). Non-ionizing ultraviolet radiation is divided into three categories based on wavelength, with UVC being the shortest wavelength range out of all three of the categories. Although UVC is non-ionizing, it still has a relatively high energy level due to it being the junction between ionizing and non-ionizing radiation and is actually used as a mutagenic agent in plant due to DNA having a strong absorption maximum at the wavelength UVC is present in; this combined with the fact that UVC photons are of high energy makes creating high amounts of DNA damage, similar to those caused by ionizing radiation, easily done quickly. A UVC level of 3 W/m²  is the assumed irradiance on Mars based on the results of a study done by A. C. Schuerger of University of Florida. The result of this experiment could be used to question whether or not the light present on Mars could reasonably be used for plant growth without further processing. Methods of processing that could be utilized are filters or possibly using a solar panel to harness energy to use a much safer LED light system.