Meet the Team: Selenar Fungi

Selenar Fungi is a project carried out by 4 students: Josu Egea Carro, Vassily Antarakis, Andreas G. Gahwiller, and Avanthika Ravi. The idea came about when the team members met for the first time at the ESA/ELGRA Gravity-Related Research Summer School 2023, and the initial pitch was developed over the past year. The goal of the project is to enhance the growth of plants in a simulated lunar environment through the use of mycorrhizal symbiotes.

Plants will undoubtedly play an important role in future lunar exploration missions, whether as a food source, a part of life support systems, or for scientific study. It has also been shown that plants can be grown in the locally available lunar regolith, the layer of rock and dust covering the surface of the Moon. Yet this substrate poses many challenges, as regolith is very nutrient poor and is formed of very fine and sharp particles which slow down root formation. In addition to the regolith itself, plants grown in a lunar greenhouse would experience a different level of gravity, which is around 1/6th that of Earth's gravity.

A large majority of plants on earth form mutualistic relationships with a special group of mycorrhizal fungi. The fungus forms a network of root-like structures around the roots of its host plant where it gathers water and nutrients. These are supplied to the host in exchange for photosynthesised carbohydrates. This symbiotic relationship is especially valuable when plants are grown in nutrient-poor substrates, such as lunar regolith.

As lunar material is very hard to come by on earth, the team will use a regolith simulant specifically produced to emulate samples collected during the Apollo missions. To simulate the Moon’s gravity, the experiment will be conducted on a Random Positioning Machine, or RPM. This is a machine that can spin a central platform in three dimensions, seemingly at random, to mask the effect of earth's gravity. By averaging out gravity vectors, the machine can simulate any desired gravity level between that of earth, and microgravity.

To better understand the effect that gravity has on the mycorrhizal relationship, the experiment will also be mounted on ESA’s Large Diameter Centrifuge. The LDC has four arms on which gondolas can be mounted and swung around a central axis, exposing them to centripetal forces ranging from 1g and up to 20g, depending on the configuration.

The students designed a box to contain some seeds in lunar soil, with growth encouraged by maintaining optimum temperature, humidity, and luminosity conditions within each compartment. Furthermore, the box ensures that during rotation, the lunar soil and the seed growth will hold their position using a control barrier material.

The campaign will start in September and will consist of 2 experimental runs, each lasting for two weeks. The first experimental run will have the seeds grow from a substrate containing mycorrhizal fungi and the second run will use a substrate without fungi. For each experimental run, the team will mount prepared boxes onto the RPM and LDC, simulating lunar gravity, 2g, and 4g conditions, and controls will grow on normal gravity beside each platform.

Following the conclusion of all experimental runs, team Selenar Fungi will analyse the physiological features of the samples, including the size and shape of leaves and cells, as well as the nutrient and water contents of the plants. Collected data will provide greater insight into plant and microbe behaviour under different gravity conditions. Should the experiment detect a significant positive effect from the mycorrhizal symbiosis, it could provide a precious means of improving plant growth on future lunar missions.

You can follow the progress of team Selenar Fungi on LinkedIn and Instagram.