Long-duration space missions to the Moon or Mars present one of humanity’s greatest scientific and logistical challenges: how to ensure astronauts receive a sustainable and nutritious food supply without relying on resupply missions from Earth. Traditional storage-based solutions are not viable for journeys spanning years, while cultivating food in microgravity has yet to prove efficient at scale. Addressing this, the European Space Agency (ESA) has launched an ambitious pilot initiative known as HOBI-WAN, short for Hydrogen Oxidising Bacteria In Weightlessness As a source of Nutrition. This project seeks to determine whether protein can be generated from gases in space conditions, potentially transforming life-support systems for future exploration.
ESA’s HOBI-WAN: Turning thin air into protein for space missions
The HOBI-WAN project represents a critical step in advancing the self-sufficiency of human spaceflight. It is being implemented under ESA’s Terrae Novae Exploration Programme, which focuses on preparing Europe for sustainable exploration missions beyond low Earth orbit. The initiative is a collaboration between OHB System AG, a long-standing ESA partner with deep expertise in International Space Station (ISS) payloads, and Solar Foods, a Finnish biotechnology company that has pioneered gas-based fermentation systems.At the core of the project lies Solar Foods’ Solein technology, a process that uses hydrogen, oxygen, and carbon dioxide to feed specific bacteria capable of producing a protein-rich powder. The powder, known as Solein, is entirely independent of sunlight or agricultural land, offering a radically sustainable alternative to conventional food production. The HOBI-WAN experiment aims to validate this process in microgravity and determine whether the bacterial fermentation cycle can remain stable under spaceflight conditions. According to ESA, the ability to produce food using onboard gases could allow astronauts to recycle vital resources and reduce dependence on Earth-based supply chains.
How Earth-based science is preparing for life in space
The scientific foundation of the HOBI-WAN project is grounded in microbial biotechnology, where certain strains of bacteria can synthesise proteins using chemical energy derived from hydrogen oxidation. These microbes are housed in bioreactors that simulate controlled environmental conditions. On Earth, Solar Foods has successfully demonstrated this process to create Solein, a single-cell protein powder composed of approximately 65–70 percent protein content, along with carbohydrates, fats, and minerals.In space, the adaptation of this technology presents a series of technical challenges. Hydrogen and oxygen must be precisely injected into the bioreactor without fluid leakage, as even minor errors could lead to safety hazards due to the gases’ reactive properties. Additionally, urea derived from astronaut waste may replace ammonia as a nitrogen source, allowing the process to close vital metabolic loops within spacecraft ecosystems. The experiment’s housing, a standard ISS middeck locker, will include incubation systems, sensors, control units, and sampling mechanisms to enable real-time monitoring. Astronauts aboard the ISS will extract and preserve samples for later analysis to determine protein yield, purity, and microbial stability under weightless conditions.
How hydrogen and carbon dioxide can become food
A recent study published in Nature Food outlined the efficiency of gas fermentation systems for converting carbon dioxide into edible biomass using hydrogen-oxidising bacteria. This form of bioconversion has been identified as one of the most resource-efficient protein production methods known, requiring up to 100 times less land and water than soy-based cultivation. In the context of spaceflight, where every kilogram of cargo is critical, HOBI-WAN’s concept of “closed-loop biomanufacturing” could become a cornerstone of extraterrestrial nutrition systems.The microbial process functions by feeding a culture of Xanthobacter species with hydrogen, oxygen, and carbon dioxide. The bacteria metabolise these inputs to synthesise amino acids and other biomolecules essential for human nutrition. The end product, a fine yellowish powder, can then be processed into various food forms or serve as an ingredient for reconstituted meals. Beyond its nutritional potential, this approach exemplifies circular resource utilisation, as waste carbon dioxide exhaled by astronauts could be recaptured and reused to produce food, creating an almost self-sustaining life-support ecosystem.
Linking space technology with sustainability on Earth
While HOBI-WAN’s immediate goal lies in space exploration, its broader implications extend to global food security. OHB Project Manager Jürgen Kempf has emphasised that the insights from this experiment may help address resource scarcity challenges on Earth, particularly in regions where arable land and fresh water are limited. The same microbial protein production techniques could be scaled to industrial levels, reducing dependence on traditional agriculture and significantly lowering greenhouse gas emissions associated with livestock farming.ESA’s Chief Exploration Scientist, Angelique Van Ombergen, has described the project as a “key capability” for ensuring autonomy and resilience in human spaceflight. For future missions to Mars, where resupply intervals could extend for years, the ability to generate food on demand would mark a transformative shift in mission design. The first phase of HOBI-WAN, lasting eight months, focuses on refining the Solein production model on Earth, while the second will prepare and test flight-ready equipment for the ISS. Once operational, the bioreactor will serve as a prototype for larger systems that could one day sustain lunar habitats or interplanetary spacecraft.The HOBI-WAN project not only explores the boundaries of biotechnology and engineering but also embodies the emerging philosophy of sustainable exploration. By demonstrating that essential nutrients can be produced from basic gases, ESA’s research teams are redefining what it means to live independently from Earth’s biosphere. The project’s success could set a precedent for future innovations, where the same principles enable both spacefarers and terrestrial populations to thrive under limited resources.Also Read | Meet the ‘Spider-Man lizard’: The science behind the Mwanza flat-headed rock agama’s superhero colours
