Spanish astronaut Pedro Duque visits the MELiSSA Pilot Plant

Astronaut Pedro Duque visited today the MELiSSA Pilot Plant located at the UAB School of Engineering together with representatives of ESA, the UAB and the MELiSSA Consortium. The laboratory is part of the European Space Agency (ESA) MELiSSA project and aims to be a unique facility in Europe for the demonstration of Closed Loop Life Support Systems, paving the way for human autonomy during long duration space missions.

MELiSSA is a regenerative circular system for food, water and oxygen recovery from wastes, carbon dioxide and minerals. In October 2021, the MELiSSA Pilot Plant completed an 18-month-long experiment involving the continuous operation of 3 of its 6 compartments, with an excellent and robust performance, representing a remarkable proof of concept of the approach followed in its development.

The experiment consisted in the connection of the nitrification unit (preparing the nitrogen source), the micro-algae compartment (producing the food precursor biomass, fixing CO₂ and producing oxygen) and the mock-up crew of rats mimicking the respiration of astronauts (consuming oxygen and producing CO₂). It enabled testing the capacity of the MELiSSA loop in terms of food complement production, water recycling and oxygen generation, working under a dedicated control system, in a continuous, dynamic, long-term experiment, representative of missions in space. Additionally, the plant growing compartment is also ready to start the connection to the MELiSSA loop.

An innovative project of the European Space Agency

MELiSSA is the acronym for Micro-Ecological Life Support System Alternative, an innovative project of the European Space Agency that was initiated as part of a research programme on life support technologies, in order to facilitate long-term manned space missions such as Mars Transit Habitat.

These types of missions cannot be performed without regenerative life support systems like MELiSSA that will drastically reduce the amount of logistics needed to support the crew. For this, a regenerative circular system is proposed, with the generation of edible material from higher plants and microalgae, revitalisation of the atmosphere for respiration, recovery of water, and recycling of the wastes generated by the crew and plant growth.

The MELISSA project is targeting ideally 100% recycling of all chemical elements, i.e. a fully self-sustainable ecosystem without any resupply. In terms of processes, control, stability, safety, robustness, etc., this target represents a very high challenge.

The recycling challenges of MELISSA are re-enforced by the closed environment conditions and the presence of humans. As a consequence, intensive characterization, safety analysis comprehensive integration, verification, validation and qualification activities are mandatory steps in the development and validation of MELiSSA.

In 2009, the second generation laboratory for the MELiSSA Pilot Plant at the UAB began its activities, providing a world class research and development facility. In the past years, several achievements have been made in the progressive construction of the different blocks comprising the MELiSSA Pilot Plant.

To be highlighted, the operation of three compartments of the MELiSSA Pilot Plant during a long-term period of 18 months was successfully achieved by October 2021. “The successful operation of three compartments for a period of one year and a half under continuous and controlled operation demonstrates the scientific and technological capabilities of the project”, said Director of the plant, Francesc Gòdia Casablancas, professor at the Department of Chemical, Biological and Environmental Engineering of the UAB and researcher from the Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya) at the Centre for Space Research (CERES, IEEC – UAB). These three compartments were the nitrification bioreactor, the microalgae photobioreactor and the animal isolator as a crew mock-up.

Solid progresses on board the International Space Station

In parallel, solid progresses have been achieved as well for space demonstration on board the International Space Station, such as the photobioreactor ARTEMISS (demonstrating the growth of microalgae in Space), the new experiment BIORAT 1 and 2 (demonstrating the operation in continuous mode of nitrification and microalgae photobioreactor) and the PFPU (modular food production complement unit for plant growth), in preparation. Therefore, the demonstration of continuous process obtained in the MELiSSA Pilot Plant in terrestrial conditions will be further explored in Space conditions.

International and multidisciplinary collaboration

The MELiSSA project is an international and multidisciplinary collaboration with a core team of fourteen partners, including ESA, i.e. SCK/CEN (Mol, B), VITO (Mol, B), University of Ghent (Ghent, B), University of Mons (Mons, B), Universitat Autònoma de Barcelona (Barcelona, E), University of Guelph (Guelph, CND), University Clermont Auvergne (Clermont-Ferrand, F), SHERPA Engineering (Paris, F), Enginsoft (Bergamo, IT), University of Napoli Federico II (Napoli, IT), Univeristy of Lausanne (Lausanne, CH), IPStar (Vught, NL), and the MELiSSA Foundation (Brussels, Belgium). The coordination of the consortium is done by ESA, at the request of the rest of the partners. As the project develops, more and more European companies and organisations are contributing to the joint venture, bringing complementary expertise where needed (today more than 50 organizations from 12 countries have contributed to MELiSSA).

The scientists and engineers in MELiSSA come from various backgrounds (academic organisations, industries) and together provide comprehensive, multidisciplinary expertise (microbiology, modelling, process engineering, biotechnology, system engineering, nutrition, automation, genomics, proteomics, etc.).