Biosphere 2, the sealed ecological research facility near Oracle, Arizona, is hosting a set of interdisciplinary experiments in 2025 aimed at two broad questions: how life began on Earth and how humans could live for extended periods on barren worlds. Scientists from multiple institutions are using the enclosed habitat to recreate, as closely as possible, the environmental conditions that shaped early life and to test integrated life-support systems that could sustain people on other planets. The work blends geochemistry, microbiology, plant science, and systems engineering, and it follows a long arc of investigation that began decades ago at the same site.
Origins of life in a closed system
The origins track within the current program treats the Biosphere 2 chambers as laboratories for probing how prebiotic chemistry could assemble into living systems under controlled, Earth-like conditions. Researchers are recreating environments that could have existed on the young planet—from shallow coastal zones to mineral-rich subsurface contexts—and introducing microbial communities and simple organic substrates to observe how complexity emerges.
In this setup, scientists monitor chemical fluxes, energy transfer, and mineral–microbe interactions that would have influenced the formation of protocells and the first metabolic networks. By varying factors such as temperature, redox state, ultraviolet exposure, and nutrient availability, the team aims to identify robust chemical pathways that could plausibly bridge chemistry and biology. The work emphasizes careful, traceable measurements of gas composition, isotopic signatures, and the activity of microbial consortia that can drive key steps in carbon fixation and energy cycling.
What the origins experiments are testing
The experiments test several core questions. How do simple organic molecules gain complexity in the presence of minerals and microbial catalysts? What roles do mineral surfaces and porous soils play in concentrating reactants and facilitating reactions? How resilient are early biosignatures when environmental conditions shift, and what signals might we expect in ancient rock records that indicate life’s emergence?
Building a habitat for human explorers
Alongside origins research, the project investigates how to design closed-loop systems capable of supporting human crews for months or years in space or on other planets. The “habitability” track emphasizes regenerating air, water, and nutrients while producing food in a way that minimizes external resupply. The experiments explore the integration of crops, microbes, fungi, and invertebrates into a single, functioning ecosystem that can adapt to stress, rebalance methane and carbon dioxide levels, and recover from partial system failures.
Key questions include how to maintain stable climate and atmospheric composition inside a compact habitat, how to recycle brine and wastewater into usable resources, and how to ensure plant productivity under varying light, gravity, and radiation conditions. Lessons from these studies feed into broader models for far-flung missions, such as crewed expeditions to Mars or long-duration stays on the Moon, where in situ resource use and autonomous management will be essential.
How the habitability work translates to space missions
Researchers are designing and testing multigenerational food production schemes, integrated waste processors, and bioreactor systems that pair photosynthetic organisms with microbial communities to close the waste loop. By validating these systems in a near-realistic, Earth-based environment, the team aims to reduce the risk of life-support failures on deep-space missions and to improve the sustainability of off-world habitats.
One emphasis is on modularity: components that can be upgraded or replaced without major redesigns, allowing habitats to adapt to new mission profiles. Another is resilience: ensuring that if one subsystem falters, others can compensate while sustaining crew health and safety. The results also inform Earth-based applications, such as improving crop resilience in extreme environments and advancing soil rehabilitation techniques in degraded landscapes.
What the measurements are showing
- The closed-system experiments continue to reveal how microbial ecosystems respond to shifting redox conditions and nutrient supplies, highlighting the importance of microbial diversity for stability.
- Plant–microbe partnerships emerge as critical drivers of nutrient cycling and gas exchange, with root-associated microbes helping to mobilize nutrients in low-biomass soils typical of early Earth analogs.
- Gas flux data indicate that oxygen levels, while stabilizing, can exhibit short-lived fluctuations in response to changes in photosynthetic rates and soil respiration—findings that inform how real-world life-support systems might handle variable energy and resource inputs.
- Isotopic signatures of carbon and oxygen provide clues about pathways of carbon fixation and organic matter turnover, offering a window into how ancient biospheres could leave detectable records in rocks and sediments.
- In the habitability experiments, crop yield analyses under controlled environmental stress tests help map sustainable production corridors for long-duration missions, including how to balance calorie output with water and nutrient inputs.
Historical context and evolving interpretation
The Biosphere 2 project has a long, complex history. The original construction and a famous, high-profile closed-system experiment in the early 1990s drew both admiration and critique as researchers faced unanticipated challenges in maintaining the ecosystem. Since then, the facility has undergone management changes and renewed scientific focus, with ongoing collaboration among universities, government agencies, and international partners. The current program reflects a matured, multi-disciplinary approach that treats the enclosure not as a single experiment but as a living laboratory capable of running parallel tracks—one that probes Earth’s origins and another that informs the practicalities of space exploration.
In this frame, researchers emphasize that the origin questions remain inherently complex and debated within geology and biology. The closed-system results contribute to a broader tapestry of evidence about how life could arise from nonliving chemistry, how early atmospheres evolved, and how planetary conditions constrain the pace and pathways of biological development. The habitability work, while grounded in engineering and ecology, likewise engages with policy considerations around sustainable life support, long-term spaceflight readiness, and the ethical dimensions of early-stage planetary exploration.
Implications for Earth science and space exploration
The 2025 results underscore a convergence between fundamental science and applied engineering. On Earth, the experiments help scientists study nutrient cycling, soil formation, and ecosystem resilience in environments that resemble early continents or degraded landscapes. The methods developed—precise gas flux measurements, high-resolution sequencing, and controlled environmental perturbations—could be applied to studying contemporary climate-associated shifts in soils and wetlands.
For space missions, the research contributes to a blueprint for self-sustaining habitats that minimize resupply needs and maximize crew safety. By demonstrating how to orchestrate plant production with microbial and inorganic processes in a confined space, the work supports the design of future bases on the Moon or Mars that can sustain human curiosity for years at a time.
Outlook and ongoing work
Looking ahead, the team plans to extend the duration of several parallel experiments to capture longer-term dynamics in both origin-focused and habitability-focused tracks. Researchers will continue to refine measurement techniques, including real-time monitoring of gas exchanges, microbial community monitoring with metagenomics, and advanced modeling to connect laboratory results with planetary-scale implications.
The broader scientific takeaway is that life’s emergence and its maintenance in closed systems depend on a delicate interplay among energy sources, chemical gradients, and biological consortia. While a definitive account of how life began remains elusive, the Biosphere 2 program is contributing essential data about the plausible conditions under which life could arise and the engineering strategies that could sustain life beyond Earth.
Key takeaways at a glance
- Biosphere 2 serves as a dual-purpose laboratory for abiogenesis research and for developing closed-loop life support for space missions.
- Two parallel tracks—origins and habitability—are studied in concert to inform both Earth science and future human exploration missions.
- Early results highlight the importance of microbial diversity, plant–soil–microbe interactions, and stable gas exchange in sustaining closed ecosystems.
- Findings have implications for understanding Earth’s past and for designing resilient habitats on the Moon, Mars, and beyond.