Five years ago today, SAM was born.
If we had known that half a decade later we’d still be building, well, we might not have had the courage to dive in. This is how entrepreneurs get things done — naive to the labor ahead (no matter how many projects have been engaged before) and full of energy, you take the first step and then start running.
by Luna Powell
For the 4th year, the National Space Society took around 80 middle school students on an overnight weekend trip to Biosphere 2 for their annual space design competition. The students had the opportunity to visit SAM for a tour with Luna and Matthias. Together, they put 20 students on the Reduced Gravity Simulator, provided an educational, geological tour of the SAM Mars Yard, and provided an external tour of SAM. Many of the students said that the knowledge they learned during the tour will help them during the competition! Thanks to Ty White who helped organize and set up the tour for his students.
by UofA Research & Partnerships
How do we breathe, eat and recycle on the Moon or Mars without relying entirely on machines?
Inside Biosphere 2’s SAM habitat, U of A researchers completed the first human-involved bioregenerative life-support trial at the facility since 1994. For two weeks, researcher Matthias Beach lived sealed inside the Space Analog for the Moon and Mars, or SAM to test whether crops, not machines, can maintain breathable air in a closed system.
The experiment ran in coordination with the World’s Biggest Analog mission, linking 16 space habitat simulations worldwide. Inside SAM, 144 dwarf pea plants sequestered CO₂ through photosynthesis for the first week. After harvesting the plants mid-mission, CO₂ levels rose, offering a clear, measurable comparison of plant-based carbon drawdown in space-like conditions.
This work will feed into a 22-crop database to help NASA and future mission planners determine how plants it might take to sustain people on the Moon or Mars.
This phase of assembly requires in-house fabrication of key, custom components, fittings, and seals. University of Arizona undergraduate students Alyssa Ackerman, Brendan Phoebe, and Jeff Buskirk joined the SAM team mid October to work along side lead engineer Griffin Hentzen, and in 2026 will assume his role, as a team, when he ends his one year engagement at SAM.
The filters, gaskets, and seals internal to the chamber stack and between the chambers, and introduction of a commodity water chiller in combination with a heat exchanger provides a closed coolant loop to maintain adequate low temperatures for maximum efficiency of the total system.
Alyssa, Brendan, and Jeff each bring a unique experience, valued skills, and confident energy to this project, and are already contributing to the overall project at an incredible rate.
Experiment | Design | Components | Assemble | Fabrication | Operation (coming soon)
by Griffin Hentzen, ME
We are thrilled to enter the assembly phase of the project! We have all primary components needed to build the assembly, with many system components already mounted on the grid wall. Unlike most spaceflight hardware which is tightly packaged to maximize efficiency, our system has plenty of room. We are opting to make the assembly modular and spread components out as much as needed to make assembly, integration, and testing as easy as possible. This unit will be an experimental unit that we will want to be able to upgrade or alter at any given time.
The large chamber stacks have many different sections. At both ends, they contain diffuser chambers which simply allow the air to transition from a relatively thin tube into the full volume of the chambers. The largest chambers within each chamber stack are the sorbent and desiccant chambers. The sorbent chamber adsorbs CO2, but is sensitive to water vapor; the desiccant chamber adsorb water vapor to allow the sorbent chambers to function properly. The medium-sized middle chamber is a plenum chamber that contains a large check valve, and a side-exit port. The three small chambers are spacer & instrumentation chambers that allow for us to easily plug in power and data lines to components inside the chambers without compromising the seal quality. They are separate chambers to ensure modularity, and give us the flexibility to change around positions in the future.
Also mounted are the blower (blue), the blower controller (black box), and the vacuum pump (silver, white and black), which allows for us to pull a vacuum on the zeolites/sorbent to desorb them of CO2.
There are many more components in the system, including a number of valves, a heat exchanger, high-temperature tubing, and a healthy amount of instrumentation and wiring. So far we have primarily been fit testing and ensuring all components will mount correctly to the 80/20 wall. The mounting structure is designed to allow for maximum modularity and ease of assembly and maintenance compared to a system that is welded together, permanently in place. It allows us to move any given component up/down, left/right, or in/out.
Experiment | Design | Components | Assemble | Fabrication | Operation (coming soon)
Dwarf peas inside Biosphere 2’s SAM breathe new life into space habitat research
by Laine Kowalski, Office of Research and Partnerships, University of Arizona
“At the University of Arizona’s Biosphere 2, a small, airtight habitat is yielding greater understanding about how humans might one day survive far beyond Earth and on Mars. For the past two weeks, one researcher lived sealed inside the Space Analog for the Moon and Mars, or SAM, sharing his quarters with 144 dwarf pea plants.
The goal of the project was to measure how much carbon dioxide the pea plants could remove from the air and how much oxygen they could return in a closed system sustained only by sunlight, water and human breath.”
Today, Monday, October 27, at 10:50 am, SAM team member Matthias Beach exited the sealed SAM vessel following a two weeks, solo stay. He was welcomed by Dr. Linda Leigh, one of the original eight Biosphere 2 crew members from the 1991-93 sealed experiment, News Channel 13 (KOLD), a University of Arizona documentary film and reporting team, and much to his surprise, the entire assembly of the 2025 Gastronauts Conference, who asked an incredible array of meaningful questions focused on his diet, sleep, and exercise routine while sealed inside for those two weeks.
This was, to date, the longest crew stay in SAM, and the first in bioregeneration—the use of plants as a means to capture carbon dioxide (CO2) and generate oxygen. For the first week Matthias’ CO2 was partially offset by 144 dwarf pea plants grown in four hydroponics racks. At the start of the second week the peas were harvested, and his CO2 was allowed to rise for the following five days, unmitigated, for comparison. Water vapor suspended in the air (humidity) was captured, filtered, and returned to the nutrient storage tanks, one for each of the four hydroponics racks. And his uneaten food scraps were dehydrated then ground to an inert powder to be fed to mycelium, the root structure of edible mushrooms.
Matthias’ answers were insightful and moving. He shared how important this experience was to him, as a US veteran who served in Kuwait and has since worked principally in IT and construction, to have this opportunity to not only help build SAM but then participate in this pinnacle study. He emphasized the need for a strong daily routine, a solid ‘flight plan’, and how his time alone allowed him to explore a vegetarian diet, play guitar, read printed books, watch 1940s sci-fi films, and paint for the first time in his life. He carefully described his awareness of the plants that sequestered the carbon dioxide he generated, witnessing how each plant was unique, some with fruit bodies, some without.
Prior photos essays provide the details of this endeavor:
Matthias Beach completes first week in SAM — October 21
Matthias Beach enters SAM for two weeks stay — October 13
Bioregeneration at SAM: A two weeks solo mission — October 12
SAM is built on a foundation laid by sixty years of prior experiments, starting with BIOS3 at the Institute of Biophysics in Krasnoyarsk, Russia (1965-1972); Biosphere 2, Oracle, Arizona (1991-93, 1994); Closed Ecology Experiment Facilities (2005-07); and Lunar Palace by Beijing University of Aeronautics and Astronautics (2014, 2017-18). Each of these pivotal projects provides lessons learned and support for the next generation of complex experiments and scientific outcome. Learn more about human space exploration analog research, worldwide.
This experiment in bioregeneration at SAM is an integral component to the University of Arizona thesis for Masters candidate Atila Meszaros and UA undergraduate student Luna Powell, and concludes four of five controlled experiments (one more to go). The in-house design and constructed hydroponics system is an extension of the decades experience held by the University of Arizona’s Controlled Environment Agriculture Center (CEAC) with support by Dr. Gene Giacomelli, Dr. Triston Hooks, and Dr. Murat Kacira, and is being operated in collaboration with Dr. Lucie Poulet at the Bioastronautics & Life-Support Processes at University Clermont Auvergne, France. The dwarf pea employed was developed by Dr. Bruce Bugbee at Utah State University. And continued thanks to Dr. Ray Wheeler, NASA KSC for his work in controlled environment plants studies that lay the foundation for our food cultivar based bioregeneration.
“It is my honor to thank my on-site and extended team for the tireless effort this past two and a half years, since the very first team was sealed inside in April 2023. Bindhu, Bryan, Cameron, Carter, Chris, Colleen, Ezio, Franco, Griffin, Ivy, Jacob, Jason F. and Jason D., Kai “Nevers”, Linda, Luna, Madelyn, Matthias, Nathan, Shantanu, Tasha, and Trent—you have each played a vital role in our shared success. And this is just the beginning, with many more experiments to come. And continued gratitude to our Executive Director Jaoquin Ruiz, Deputy Director John Adams, and the UA Biosphere 2 staff.” —Kai Staats, Director of Research for SAM
Researcher exits sealed Biosphere 2 facility following two-week experiment
October 27, 2025, 5:00 PM MST
TUCSON, Ariz. (13 News) – For the first time in more than three decades, a human was sealed inside a Biosphere 2 facility with nothing but plants to clean the air.
Matthias Beach spent two weeks sealed in SAM, or the Space Analog for the Moon and Mars, a 1,100 square-foot facility meant to simulate a spaceship.
“I can’t wait to do it again, believe it or not,” Beach said after exiting the pod.
The experiment monitored Beach’s carbon dioxide emissions. For the first week, he lived alongside 144 pea plants, which cleaned the air of CO2. During the second week, the plants were removed from the facility, theoretically increasing the amount of carbon dioxide in the air.
While data hasn’t yet been analyzed, Beach said sensors showed an obvious increase in CO2 emissions once the plants were removed – something he noticed while living in the pod.
“You can definitely smell the difference and smell the humidity and smell the green in there, and without it, it seemed kind of like a spaceship,” Beach said.
The goal is to determine which plants are best suited to bring to space when we become an interplanetary species – making space travel as Earth-like as possible. “It provides, obviously, nutrients and calories. It also provides a means by which we can capture carbon dioxide and convert it to oxygen, which happens around us every single day in the real world. And it provides a psychological benefit – people love working with plants,” said Kai Staats, the research director on the project.
Staats said this is just the start of years-long experimenting that will further their knowledge on how the future of space exploration may look. “When a human’s physiological patterns are slightly chaotic, that introduces a chaotic function to the system – we need to know that,” said Staats.
Beach said he’s just excited to be a part of something that might turn into something huge.
Copyright 2025 13 News. All rights reserved.
CORRECTION—in the video segment (top), the new anchor incorrectly states the mission was conducted inside of Biosphere 2; and the reporter states SAM is a “Space Analog for the Moon and Stars” but should be “Moon & Mars”.
SAM team member Matthias beach has been sealed inside of the SAM vessel for one week. His days are filled with a variety of tasks: eating, exercising, writing in a journal, completing surveys for one or more World Biggest Analog projects, recording video logs, monitoring 144 dwarf pea plants growing in four hydroponics racks, and overall maintenance of this SAM facility.
What makes otherwise mundane tasks unique is the attention to detail. Breakfast is not just warming up water for a bowl of oatmeal, but recording the mass of every bit to be consumed (water, oats, powdered milk, bagel, cheese, etc.). This is a time consuming process that is fundamental to the research endeavor.
Matthias’ carbon dioxide generation, a natural part of human metabolism, is directly affected by a variety of factors such as the amount of sugars and carbohydrates in the foods consumed, hydration, exercise, and sleep. Where Matthias is spending his time increases CO2 levels in that module (Lung, Test Module, Engineering Bay, Crew Quarters) until the higher concentration diffuses toward an equilibrium. His very movement around SAM changes the distribution of CO2 as his body acts as a circulation engine. We can see this when monitoring the four SIMOC Live sensor arrays, one for each module.
Today, at the close of week one, Matthias begins to harvest the 144 pea plants. His first priority is to deliver 48 plants, through the airlock, to Luna and Atila who will process the plants outside of SAM. In concert with Dr. Lucie Poulet and her student Louise, Researchers in Bioastronautics & Life-Support Processes at University Clermont Auvergne, France, the plants are being recorded for their height, wet and dry biomass including the fruit bodies (pea pods) separately, and leaf surface area (as determined with a flatbed scanner). Matthias’ next task is to process the remaining 96 plants inside of SAM, recording height and again, the wet biomass for the plant including the pea pods separately. Later, the plants are dried in the Biosphere 2 bio lab to capture the dry biomass. This requires two full days for one person, and was completed Tuesday evening.
The moment the first pea plant was harvested data collection for CO2 sequestration was terminated as the number of active plants is reduced. With the harvesting of the first 48 plants and air lock transfer, Matthias activated the blower and opened all valves to reset SAM to a nominal 450-500 ppm CO2. This gives us a nearly equal baseline from which the CO2 levels will again rise for the second half of the experiment.
And when the final plant was harvested, the blower was turned off and all valves were closed. In the second half of the experiment Matthias will continue with his measured food consumption, exercise, and sleep schedule such that his activities and associated CO2 generation will be nearly identical, day for day, to the first week in SAM.
As such, we will have, for comparison to our predictions, one week with pea plants and one week without. Without giving away the core of our publication, we are seeing a very strong correlation to the presence of the peas, somewhere between 35-50% reduction in CO2 from our predictions. This estimation is wide, at this point, as we have run quick calculations based on just one of the four sensor arrays, and not yet taken into account the four very different volumes of air in which each sensor sits.
As stated in prior entries related to this project, the end goal is to understand a) the amount of CO2 produced by one human crew member over an entire day, and b) the amount of CO2 processed by one dwarf pea plant, or the CO2 sequestration by one square meter such that we can ultimately inform future space fairing entities the number of food cultivars required to offset the CO2 produced by a crew.
SAM team members Matthew Rusek-Peterson, Luna Powell, Matthias Beach, Dr. Linda Leigh, Atila Meszaros, Griffin Hentzen, and Kai Staats.
The SAM team arrived on-site at 6 AM, Luna Powel, Atila Meszaros, Griffin Hentzen, and Matthias Beach immediately diving into a list of TODOs before the solo, sealed mission began. Kai Staats joined them to replace the pump on the water manifold and configure the SIMOC Live and Vernier sensor arrays. While SAM has since April 2023 seen five crewed teams and 31 individuals for more than 126 total person days, or 3038 total crew member hours—there is always something more to prepare for the next human-in-the-loop experiment.
SAM is an active research center, ever growing in its capacity to support a diversity of experiments. With a series of foundational bioregeneration experiments completed this spring and summer, this solo crew member, two weeks stay is the culmination of more than seven years research, development, fund raising, and construction.
Master of Science candidate at the University of Arizona Atila Meszaros’ thesis experiment is the demonstration of the capacity for the sequestration of carbon dioxide and production of oxygen by a single food cultivar, in this case, a dwarf variety of pea developed by Dr. Bruce Bugbee at Utah State University.
SAM has from the start been guided by the original experiments conducted by the “Biospherians” from 1986-1990, while they were designing and then constructing the Biosphere 2. While several of those individuals did stay inside the Test Module, the prototype for the Biosphere 2 that now serves as the controlled environment (greenhouse) for SAM, Linda Leigh remained inside for three weeks without outside air, food, or water.
At 10:57 am Matthias Beach hefted his personal duffel bag, shook hands with Director of Research Kai Staats, and was ushered into SAM through the airlock by Linda Leigh (photos at bottom), continuing her tradition of seeing all of SAM crews into and out of SAM. Matthias’ stay will be the longest mission in SAM to date, and the first long-duration in which the pressure vessel will operate in Mode 0, unpressurized and sealed. In this manner we minimize the leak rate by essentially negating the pressure differential from inside to outside, with all valves closed and blower off. With four internal air handlers the temperature remains relatively constant, thereby reducing the expansion and contraction of the internal air from day to night.
As noted in the previous post there are 144 pea plants growing in hydroponics. At the close of six weeks (from seed) they are at a peak maturity, meaning they will, in theory, provide the maximal uptake of carbon dioxide and production of oxygen. However, our math models suggest that these 144 plants will provide between two-thirds and three-fourths the CO2 sequestration required. This is by design, for we prefer to see Matthias’ CO2 production be reduced by an observable amount rather than brought to zero, where we would not know precisely the number of plants that did in fact offset his CO2 production.
In this manner we can take his personal CO2 production baseline over 58 hours (conducted earlier this year), establish an hourly rate, multiply by 7 days [14 days x 24 hrs x ppm per hour], and quickly gain a ballpark approximation for his peak level. We then monitor the real CO2 over this seven day period and compare: subtract the actual CO2 level after one week from the estimated peak, divide by square meters of plants or by the number of peas plants, and we have a rough estimate for CO2 sequestration by dwarf peas.
Finally, to validate this model we go one step further. On day 8 Matthias will harvest all of the peas, conduct a series of measurements (size, shape, mass) to assist in Atila’s research, retain some of the peas for his consumption, and then pass all remaining biomass through the airlock for external processing by Atila and Luna. As such, his second week will see Matthias without external air injection or CO2 sequestration of any kind. As we already know his baseline, we have estimated the ceiling and know that he will be within a safe level.
This final week gives us a comparison of our model vs reality, and a solid understanding of SAM itself in the context of plant growth with computer controlled CO2 injection, human CO2 generation, and then sans any scrubbing at all. This three prong approach provides a vital understanding as we look to a future in which we are living off of this planet and among the stars. And as with Biosphere 2, it also gives us a deeper appreciation for how our animal functions do interact with the plants of Earth each and every day.
Enjoy a few historic photos of the B2 Test Module, and Linda Leigh’s 1990 three weeks stay inside, followed by the informal gathering to send Matthias into his sealed mission.
