FAQ
Answers to the questions we’re asked most often about the MELiSSA project and the Foundation.
What are MELiSSA’s objectives, and what is the overall strategy?
MELiSSA is working towards a fully closed-loop life support system for human space exploration, built on a detailed understanding of the biological and chemical processes involved, engineered for crew safety and long-term stability, and transferred to Earth applications wherever it can help. Doing that also means building an international scientific and industrial ecosystem, and training the people who will carry the work forward. See What It’s Trying to Achieve for the full picture.
Can MELiSSA only be used on the Moon or Mars?
No: MELiSSA can be used for the transit phase of a mission as well as for a surface habitat, and it does not have to be all or nothing even within a single mission. The project’s approach is organised by function, oxygen production, water production, urine nitrification, food production, so mission planners can draw on part of the loop, or the complete architecture, depending on what a given mission actually requires. Comparing and selecting the right architecture for that mission is done using the ALiSSE criteria: efficiency, mass, energy, safety and crew time.
The same logic extends further than Moon or Mars missions. The physics that make regenerative life support necessary for a Mars habitat are exactly the physics that make it useful anywhere resources are scarce or resupply is expensive: a space station, a polar research base, a disaster relief camp, or a city running short of water.
The project echoes a broader global shift towards circular thinking, driven by the same pressures a crew faces on a long-duration mission: population growth pushing past nine billion by 2050, the depletion of fossil fuels, accelerating climate change, and the food, water and energy independence lessons of COVID-19 and the war in Ukraine. MELiSSA’s answer to all of these, in space or on Earth, is the same: there is no such thing as waste, and it helps to think like an astronaut.
The consequences of that thinking are concrete rather than aspirational. The MELiSSA Pilot Plant and the Concordia research station in Antarctica have proven closed-loop water and biological systems can run reliably for years at a time, and that work has already been transferred into wastewater treatment, agrofood, sanitation and building projects across Europe and beyond. Moon and Mars remain the mission that justifies the research; they are no longer the limit of where it applies.
What makes MELiSSA hard?
Designing a circular system demands a top-down view: every building block of the loop is connected to every other, so no single block can be designed in isolation from its effect on the whole. Space adds its own constraints on top of that, reduced gravity and radiation among them. See What Makes It Hard.
How is the project organised?
MELiSSA brings together 16 formal partners and at least 50 other organisations (universities, research institutes, ESA and industrial companies) around a set of interconnected compartments that mirror a natural ecosystem’s functions: waste treatment, microbial conversion, nutrient regeneration, higher plants, and the crew itself. See Scientific Concept.
Who can join MELiSSA?
MELiSSA is built as an open, international ecosystem, and there are several routes in, depending on what an organisation or individual brings to it.
Universities, laboratories and public research centres working on biology, water treatment, microbial processes, environmental engineering, modelling, agriculture or life-support technologies.
Companies developing technologies in water recycling, sanitation, waste valorisation, controlled-environment agriculture, sensors, bioreactors, monitoring systems or energy-efficient processes, especially those seeking dual-use space/Earth applications.
Agencies, municipalities and public organisations interested in deploying circular technologies, piloting innovative systems or contributing to long-duration space exploration strategies.
Early-stage companies with novel ideas or breakthrough technologies that can strengthen the circular, regenerative or autonomous aspects of the MELiSSA ecosystem.
Through internships, PhD programmes and research fellowships in MELiSSA laboratories and partner institutions.
Institutions outside Europe can join through cooperation agreements where their expertise strengthens the project’s scientific or technological objectives.
Why, after more than 35 years, is the project not finished yet?
The more honest way to frame this question is the other way round: why did humanity not attempt to duplicate Earth’s own life-support functions much earlier? Humans depend entirely on the Earth’s ecosystem for oxygen, water and food, yet we have, today, no back-up for any of it. Anyone who looks closely at the challenge of building an artificial ecology quickly runs into its enormous difficulty.
MELiSSA is not the first attempt. Projects such as CELSS, CEEF, CERES and Biosphere 2 all explored similar ground over the years, and almost all of them had to stop, largely because the scale and duration of effort the challenge actually requires had been underestimated from the start. MELiSSA’s slower, more deliberate pace is, in large part, a direct response to that history.
Why so much ground research before flight experiments?
Flying a piece of hardware and finding out afterwards that it didn’t work is empirical and extremely expensive, and it isn’t the MELiSSA way. The project favours intensive characterisation of its processes on the ground first, then competes for a flight slot through international calls such as ILSRA. See Flight Experiments.
How many flight experiments has MELiSSA carried out?
Nine experiments have flown to date, aboard the ISS and the Foton capsule, almost all selected through international competition, with results published. The most recent, ARTEMISS, demonstrated the conversion of carbon dioxide into oxygen; the next flights in preparation are for plants (WAPS) and for urine (URINIS). See Flight Experiments.
Is Spirulina the MELiSSA food source?
Only partly. Spirulina (Arthrospira) is often assumed to be the MELiSSA food source, but that is only partially true. It is grown throughout the programme, and its high protein concentration makes it a genuinely valuable food complement, but the bulk of the crew’s diet in a full MELiSSA loop is expected to come from higher plants: crops such as tomato, potato, wheat, soybean and spinach, grown within the same closed-loop system that manages air and water.
How did MELiSSA begin?
The idea took shape around 1987 around the space engineer Claude Chipaux at MATRA, now Airbus, alongside scientists including Marcel Lefort-Tran, Guy Dubertret, Max Mergeay, Willy Verstraete and Daniel Kaplan. The first publication appeared in October 1988, and ESA signed the first contract in March 1989. See How It All Began.