To sustain a long-term presence on the Moon, plants need to be cultivated in-situ, preferably using materials available in the lunar environment. This minimizes costs and risks associated with transporting materials from Earth. Lunar mission soil sample research shows that essential minerals for plant growth appear to be present in sufficient quantities, except reactive Nitrogen. However, lunar soil compacts when saturated with water, which is very challenging for germination and root growth.

Hydroponic systems avoid this, as plant roots are fed directly with nutrient-rich water, enabling growth without the use of soil. In order to facilitate this, as well as the removal of undesirable compounds, an additional step is needed; beneficiation - the concentration/reduction of elements or ores from feedstock, performed utilizing several different processes including mechanical, chemical, biological etc.

The idea aimed to develop a process architecture for extracting nutrients from lunar regolith, creating fertilizer suitable for a hydroponic growing system inside a lunar greenhouse. Current systems are seemingly focused on either lunar plant growth or ISRU, whilst the proposed system would exploit synergies in combining both of these fields.

The main objective of this study was to assess what processing steps would be suitable for both regolith beneficiation and leeching agent in order to increase nutrient bio-availability. SolSys is presently collaborating with Norway’s Geotechnical Institute (NGI) and Centre for Interdisciplinary Research in Space (CIRiS) on a project titled “Lunar Regolith Simulant Nutrient Extraction - A Preliminary Study“.

In addition, SolSys has already designed, produced and sold exo-agriculture systems. This product follows hydroponic principles and has been used extensively for growing tomatoes, beans, peppers etc. Earlier SolSys experiments using lunar highlands simulant as a substrate has proven to be a success when growing beans.