Cubesat Cultivation System for the growth of a fortified “MicroTom”

Moon and Mars are consolidated targets of the human exploration of the solar system. During space mission the importance of recycling resources is clear; In this regard, plants play a significant role in every ecosystem, even when the system is a “micro” environment such as a spacecraft. Photosyntethically active plants absorb carbon dioxide, generating oxygen, fresh nutrients and clear water by transpiration process, utilizing also crew’s trashes. A space ideal “concept plant” must be a valuable source of amino acids, vitamins, antioxidant pigments, carbohydrates, proteins, and possibly bioactive molecules (i.e. immunoprotective or immunostimulants). However, to survive, plants must be placed in appropriated conditions. Life parameters must be controlled and fine regulated to improve yield and quality, especially for nutritional and nutraceutical parameters. This work is aimed to demonstrate the feasibility of raising inside a CubeSat a tomato ideotype plant (MicroTom) specifically developed for space environment in a seed-to-seed cycle. MicroTom is a small model plant (plant volume of 0.0156 m3), with short life cycle (70-90 days), able to grow under fluorescent light, easy to cultivate, with high photosynthetic efficiency and productivity (20-30 fruits/plant; 2-5 gr/fruit; mean diameter of fruits 15 mm), able of continuous flowering and of growing at high density (≥ 100 plant/m2) with good performances in hydroponic conditions. A dedicated 12 U CubeSat (23 x 23 x 34 cm), is under development for a Low Earth Orbit (LEO) mission aimed at demonstrating plant growth in extreme environments such as those estimated for future long-term space missions. The application of such payload into a CubeSat allows to start experiments in space conditions independently from the International Space Station (ISS), yet requiring verification of the complete autonomy of the environmental control systems developed. Moreover, this endeavour may represent a unique example of a plant growing in an unmanned spacecraft. The MicroTom cultivar under study has been engineered for enhanced anthocyanin content, induced by an ectopic expression of a transcriptional factor. Anthocyanins are known powerful antioxidant molecules able to protect plant from the stressful LEO conditions (i.e. gravity levels, magnetic fields and radiations). To verify health status of plants in space, the on-board instrumentation will be devised to monitor temperature, relative humidity, vapour pressure, radiation dose, O2 and CO2 and Ethylene concentration, pH and electric conductance of nutrient solution, Photosynthetically Active Radiation (PAR) and, Near-infrared reflectance (NDVI). Finally, plant growth will be monitored throughout the entire period by on-board cameras.