Astronauts on the International Space Station have tested an algae-powered bioreactor that converts carbon dioxide, water, and light into oxygen and edible, protein-rich biomass.

Oxygen is produced in the International Space Station from recycled water, which is split into hydrogen and oxygen gases using an electric current.

Technologies developed for the ISS have brought benefits to people on Earth

About 93% of water used onboard the International Space Station is recycled through filtration and purification systems that have since been used in regions lacking access to clean water. Treatments to mitigate bone loss and muscle atrophy in astronauts can also help aging adults.

Algae can capture carbon dioxide at rates up to 50 times faster than land-based plants and can be grown in tanks that use one-tenth the land footprint of terrestrial plants.

Since 2019, a free-floating robotic system named Astrobee has helped astronauts with routine tasks on the International Space Station.

Before Biosphere 2, the Soviet BIOS-3 system tested semi-closed ecosystems

Built from 1965 to 1972, the habitat hosted 10 experiments with crews ranging from one to three individuals who had their air recycled by algae and grew their own wheat and vegetables. However, dried meats were routinely brought into the facility to balance crew members’ diets.

Research suggests the cleanliness of the ISS may make astronauts unhealthy

The International Space Station's sterile conditions deprive astronauts of the opportunity to strengthen their immune systems through microbial exposure. To address this problem, future missions may use probiotic-based cleaners and foster diverse microbes in space habitats.

A prototype greenhouse for Biosphere 2 is now part of a test habitat for Mars

The Space Analog for the Moon and Mars combines the Test Module greenhouse with a workshop, kitchen, common area, sleeping quarters, and a yard that mimics lunar and Martian surfaces. A blind crew member in SAM’s first mission, Inclusion I, helped assess accessibility in potential future space habitats.

Watch how dozens of everyday human tasks are performed in space

This playlist features clips of astronauts aboard the International Space Station explaining how they cook, eat, sleep, and conduct research in microgravity. Other activities to pass the time, including watering plants and playing soccer, are also shown.

Watch what it’s like to spend a day on the International Space Station

Microgravity makes personal care more complex on the International Space Station, where stray, floating materials must be captured to prevent them from entering vents and clogging filtration vents. No-rinse shampoo, water pouches, and other strategies help minimize obstructions.

Emulating Earth’s light-dark cycle is important for astronaut health and safety

Astronauts aboard the International Space Station experience 16 daily sunrises, but scientists have learned to try to promote circadian rhythms by phasing through several light settings aboard the ISS to improve astronauts’ sleep and productivity.

How artificial photosynthesis can help make plastics and fuels using sunlight

These systems link a molecular light absorber to a catalyst that can synthesize fuels—such as ethanol—and ethylene, a precursor to plastics, in a carbon-neutral manner. Because these byproducts have greater energy concentrations than the carbohydrates produced by photosynthetic organisms, research is ongoing to engineer the necessary catalysts.

Astronauts exercise on the International Space Station

Astronauts maintain bone, muscle, and cardiovascular health with physical activity. It's crucial that they make time to exercise for approximately two hours per day. This resource offers a behind-the-scenes look at how high-intensity workouts help prevent muscle atrophy, bone density loss, and aerobic decline during monthslong space missions.

Read a firsthand account of a participant in the first Biosphere 2 mission

The first crew of “Biospherians” spent four months growing their own wheat and awaiting the ripening of tomatoes, onions, and peppers to make their own pizza. They also raised their own livestock, including chickens, pigs, and two goats named Milky Way and Stardust.

Drugs in space: the pharmacy orbiting the Earth

Researchers are developing pharmaceutical solutions for astronauts, whose bodies may not respond the same way in space as they would on Earth. Similar to how microgravity causes changes to astronaut physiology, the environmental shift enables new...

Biological terraforming studies have been conducted at Biosphere 2

The experiments involve populating barren hillslopes within the Landscape Evolution Observatory with microbes that react with air and rock to produce molecules needed by more complex organisms. Mosses and other simple plants can then grow in these spaces, gradually making them more hospitable to humans.

Astronauts follow strict schedules to mimic Earth days and stay healthy in space

Experiencing 15 sunrises and sunsets a day while aboard the International Space Station, visitors preserve their circadian rhythms and mental health with fixed timetables. Astronauts have described sleep as living in a vacuum cleaner due to ongoing air filtration.

Watch a time-lapse from space of photosynthesis across Earth

Using NASA satellite imagery, carbon absorption can be tracked and serves as a proxy for photosynthetic activity on land and in the oceans. Over the course of a year, seasonal changes can be observed as plants become dormant in the fall and active again in the spring.

Learn how environmental conditions are optimized to increase bioremediation efficacy

Through biostimulation, Indigenous microbes are provided with moisture, nutrients, or oxygen to prevent their death and ensure optimal progression of their biochemical reactions. Bioaugmentation can introduce new microbial cultures to target specific compounds not natively found in the environment, while landfarming can spread or aerate contaminated soil to improve access to contaminants.

Exposed concrete led to oxygen depletion within Biosphere 2

Instead of being absorbed by plants through photosynthesis to produce oxygen, significant amounts of carbon dioxide were taken up by the calcium hydroxide in the concrete, trapping the oxygen in calcium carbonate and water. This concrete was sealed before the start of the second B2 mission.

Scientists have collected critical minerals from ocean water using seaweed, a type of algae that leaves behind a mineral-rich powder called bio-ore after being processed into biofuels.

As an experiment, the first B2 mission highlighted the challenges of isolated systems

Some argue that isolation from the outside world was compromised—making the experiment a failure—when a crew member was taken from Biosphere 2 for surgery and returned hours later. This position was strengthened when it was revealed that oxygen had been pumped into the facility.

China developed an artificial closed ecosystem in preparation for a future lunar base

Yuegong-1, also known as Moon Palace 1, was a Beijing facility where volunteers simulated life on a colony and conducted experiments on bioregenerative life support systems to assess their viability in an off-Earth environment. The longest experiment at the 0.04-acre facility lasted 370 days.

Some algae have helped remove microplastics from water after being bioengineered to clump together with these contaminants, forming an easily collectible microplastic-algae sludge.

Mold growth in space raises the hypothesis of life being brought to Earth

Panspermia suggests that life could be carried throughout the cosmos by asteroids, comets, and other objects, but it requires organisms that can withstand the extreme cold of space travel, stellar radiation, lack of water, and intense heat of planetary impacts. The discovery of mold on the International Space Station and experiments showing it can withstand radiation in outer space-like conditions increase the plausibility of the hypothesis.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

How scientists are improving on photosynthesis

Researchers increased yield in soy plants by making them better at photosynthesis, the process that powers life. The findings hold promise for feeding a warming world.

Agrivoltaic solutions are tested in the land around the Biosphere 2 complex

The experiments involve identifying conditions needed to grow plants beneath solar panels, which protect the plants from the harsh sunlight of the Arizona desert. Research includes a citizen science component, where satellite gardens have been installed in nearby high schools.

New species of bacteria discovered in Chinese space station

A new space-adapted bacteria species, Niallia tiangongensis, was discovered on China's Tiangong space station. The bacteria display a heightened oxidative stress response and unique biofilm-forming abilities that assist them in healing from to radiation-based damage.

Instead of consuming water and carbon dioxide to produce oxygen and sugar, anoxygenic photosynthesis involves alternative reactants and products.

Space-based solar power systems may beam energy to Earth

Researchers have successfully collected power from solar panels on a plane and transmitted it to a receiver on Earth's surface, achieving a milestone for space-based energy. The proof of concept is a precursor for a satellite-based solar farm that would transmit energy 24 hours a day.

Microgravity environments improve the success of 3D bioprinting

Gravity can cause gaps, such as those in the chambers of a 3D-printed heart, to collapse before stem cells, hydrogels, and biochemicals bind together during the bioprinting process. Rather than Earth's surface, some bioprinting is done on the International Space Station, where defective organs are also printed to test treatment methods.

The International Space Station is powered entirely by large solar arrays

Launched in 1998, its original solar panels were designed to withstand no more than 20 years of wear from temperature swings and micrometeoroid impacts in space. Replacement panels that roll out like carpets have since been installed.

The Amazon rainforest is considered the 'lungs of the Earth,' but it contributes less than a quarter of the oxygen of phytoplankton—microscopic plants, algae, and bacteria capable of photosynthesis.

Why extremophiles may play an important role in terraforming Mars

Possessing unique biochemicals that can detoxify extreme environments and resilience against the Martian surface that is lethal to humans, scientists are exploring whether colonies of these organisms can transform small areas of the Red Planet into future habitats for humans. Extremophiles may also be best equipped to serve as microscopic factories for the fabrication of essential polymers.

The crew of the ISS creates unique memorials for deceased colleagues

The continued human occupancy of the International Space Station since 2000 has led to the development of social and cultural elements by crew members, which the ISS Archaeology Project has catalogued. Records of handmade cakes, decorations, and memorabilia highlight the human aspect of living in space.

Muted smell and taste in microgravity complicate meal enjoyment

Astronauts primarily consume freeze-dried meals, which are rehydrated with water recycled from urine and perspiration, directly from bags. Condiments and select cultural items from crew members can enhance the meal experience by boosting flavor. Many individuals report experiencing "food fatigue" due to a lack of fresh produce, limited menu variety, and lingering scents.

Watch underwater photosynthesis make water look like champagne

In shallow waters where sunlight can reach, photosynthetic reactions absorb water and dissolved carbon dioxide, producing bubbles of oxygen at the surface of plants. As these bubbles rise to the water's surface, a fizzy appearance is created.

Watch a livestream of Earth from the International Space Station

The feed is made possible by the SpaceTV-1 camera system, which is live over 20 hours a day. Video replays are shown during routine loss of signal communications with the inter-satellite link relaying the video data.

It is impossible for astronauts to burp in space

Due to Earth's gravity, liquids and solids sink in our digestive system, while gases rise, allowing them to be forced back up the esophagus to be expelled through burping. In the microgravity environment of the International Space Station, burping would result in vomiting if it were possible.

Bioluminescence may provide a sustainable alternative to electric lighting

French start-up Glowee is experimenting with lights made from bioluminescent microorganisms in public spaces to reduce energy use. While the technology shows promise, challenges remain with brightness, maintenance, and scaling it for widespread use.

Artificial photosynthesis turns CO₂ into sustainable fuel

Carbon conversion focuses on a central perplexing question: if carbon dioxide is a leading driver of climate change, and fossil fuels are made of carbon-based molecules, can we devise a way to convert CO₂ into useful alternatives efficiently? This video breaks down a potential pathway using artificial photosynthesis, which uses sunlight to convert CO₂ into fuel.

Questioning the results of life on K2-18b

An analysis of the atmosphere of an exoplanet called K2-18b identified the presence of biosignatures—molecules that are created by living things on Earth. This discovery may indicate life exists beyond Earth, but the lack of environmental data complicates the interpretation of results.

A look at the foods eaten by astronauts during and after the space race

After John Glenn became the first American to demonstrate that eating in space was possible by eating apple puree out of a tube, meals were prepared for astronauts to meet an approximately 2,800-calorie-a-day requirement via freeze-dried foods. Meal quality gradually improved throughout the Apollo program, including the Apollo 8 crew's nondehydrated Christmas meal in 1968.

As of 2025, scientists at B2 study the heat tolerance of cacao and coffee trees

The research at Biosphere 2 has led to the development of low-cost plant monitors, which can be provided to farmers worldwide to enable more precise monitoring of crops. Geodesic domes built within the ocean biome are used to investigate the best architectural structures for repopulating degraded reefs.

Scientists have created a cell from scratch—called a SpudCell—proof-of-concept work that a lab-made cell can feed, grow, and replicate like a natural cell.

When retired, the International Space Station will undergo a controlled de-orbit

With plans to transition low-Earth orbit operations to private entities, the ISS is expected to be retired by 2030, using a SpaceX de-orbit vehicle. Although reentry will burn up most hardware, NASA intends for any surviving debris to fall into an uninhabited ocean area.

Biosphere 2 is the largest Earth science experiment ever built

The vivarium—an enclosed system including animals and plants—is sealed from below with 454 metric tons of stainless steel liner and includes an ocean habitat with more than 700,000 gallons of seawater. B2 is visited by 100,000 people yearly, including more than 10,000 K-12 students.

Photoautotrophs, which include plants, algae, bacteria, and Euglena, are organisms at the base of the food web that convert light energy from the sun into chemical energy stored in sugars.

An artificial ‘lung’ protects the glass structures making up Biosphere 2

Although confined from much of the surrounding environment, B2 allows sunlight to enter, enabling its plants to engage in photosynthesis. Expansion chambers were built to protect the facility's integrity by managing changes in gas pressure resulting from temperature fluctuations.

Explore an interactive diary of the International Space Station

The tool enables users to learn about the daily events that occurred on the ISS since continuous human occupancy began on November 2, 2000. Upon selecting a date in the calendar, users can explore activity logs, relevant news, and multimedia content, including videos, photographs, and audiologs, from the onboard crew.