Research & Development

SAM Experimental Hydroponics v2.0

Written by Sean Gellenbeck, PhD

Initiated in mid January, the new, experimental hydroponics rack system was set in motion by SAM team members Sean Gellenbeck and Luna Powell. This upgrade is designed to be more effective and efficient in plant production, with intent to be fully computer monitored, controlled, and automated in the final design.

This single rack solution is a prototype built for use by (Hey! Is that? Could it be James Burk, Executive Director of the Mars Society helping carry in a shipment of new raceways!?)

To avoid these challenges, the redesigned system uses a different method called Nutrient Film Technique, or NFT. In NFT, a thin film of the nutrient solution is run through enclosed channels containing the plant root zones. With the roots exposed to the nutrient solution the plant can take up the nutrients and water they need. And the enclosed channels work to prevent the roots from drying out. This has the added benefit of reducing algae growth as the nutrient solution is now no longer exposed to light. As compared to Ebb and Flood the NFT design, less water is moved through the system at any one time. This results in a smaller pump and less complex structure to support the weight of the water above.

To create the new system, Sean and Luna made use of the metal support structure from the previous design. The flood trays were removed and replaced with 4 NFT channels running in parallel (side by side). The PVC channels are a standard within the hydroponics industry and are used in commercial applications. The channels were cut to size and sealed to prevent leaks onto other components. As with the original design, there are three levels in the NFT setup and the nutrient solution flows from one level to the next by gravity. However, where the previous design moved water simultaneously to all three levels, this new design carries water to the highest tray only, with gravity bringing the water to the lower two. In total, the system has 4 NFT channels flowing in parallel that connect to another set of channels on the second shelf (in series), followed by a third level of channels. The nutrient solution is pumped to the top set of channels and is split across all four channels before flowing from one level to the next. Finally, the draining solution returns to the main nutrient tank which is sized to reduce the need for crew interaction and allows for future development and system expansion.

In total, the new SAM NFT hydroponics rack has space for 78 plants. Thanks to our Jason at Biosphere 2, our team was able to quickly prepare the system with 4 species of lettuce, kale, collared greens, and a variety of herbs for the Imagination 1 crew to use during their mission.

After the Imagination 1 mission, development of the SAM hydroponics system will continue with refining the current design, duplicating it across four racks, and eventually building an automated control system to remove the need for manual crew intervention for pH and EC levels (electrical conductivity to measure of the nutrient level in solution). While much larger systems will be a part of the SAM ECLSS in the future, we expect to maintain this stand as a resource for crew experiments and education.

By |2024-04-12T06:19:26+00:00February 27th, 2024|Categories: Research & Development|0 Comments

Mars EVA suit demonstrated at Mars Society

Dr. Cameron Smith in a live demonstration of a Mars EVA suit at the Mars Society Conference 2023

The following was written by Dr. Lawrence Kuznetz:

No spacesuit to date or in the planning stage has made mitigating the forward and backward spread of potential pathogens to and from planet Earth a priority. Doing so isn’t easy. But as JFK famously said, “We do this things not because they are easy but because they are hard, and that brings out the best of us.” Which brings us to the “MarsSuit” and the MQS (Mobile Quarantine Suit), the topic of this email.

Stopping pathogen spread for the Artemis EMU was never a priority since the Apollo Program’s quarantine procedures (lunar receiving lab, etc.) found none and deemed protection unnecessary. Mars is a different story. Human missions to Mars will encounter a far more likely chance of pathogen exposure than the lunar surface.

It was for this reason that I chose Spacesuits and Life Support Systems for the Exploration of Mars as the topic of my NRC Post-doc at NASA-ARC, and followed that with a series of courses, conferences, related projects at NASA. The resulting technical outcome was using the Martian atmosphere for torso pressurization, thus enabling mass savings, puncture protection, and other radically different features. The concept maturation went on for decades as described in a plethora of reports, studies and presentations.

In the midst of the pandemic, everything changed. A mind-bending confluence of events involving a cruise ship entrepreneur and a PhD hot air balloon-jumping pressure suit designer (Dr. Cameron Smith) led to seed funding and prototype fabrication. The first “MarsSuit” prototype and a higher pressure rev 2 version verified the radically different concept of operations in 2022. It became abundantly clear that the same technology embodied in the MarsSuit’s planetary protection feature could also be migrated to a Mobile Quarantine Suit (MQS) capable of mitigating future and more serious pandemics on Earth by providing:

  • Barriers to pathogen entry or exit (BEBE)
  • Face to face exposure elimination (FFEE)
  • Cooling fog-free airflow
  • Ease of doffing and donning (2 minutes or less)
  • Lightweight comfort (less than 2 lbs)
  • Reusability (as opposed to single use PPE)
  • Rapid Disinfection ability
  • Redundant changeable and evolvable filters
  • Redundant ventilators
  • Cost effectiveness (projected <$200 / year vs >$3500 PPE / year)
  • Far greater protection than mask mandates

For more information, visit:

By |2023-10-30T20:10:29+00:00October 6th, 2023|Categories: Research & Development|0 Comments

What? No internet on Mars?!

Systems architect and administrator Christopher Murtagh is developing the server that will block ports for applications that simply could not work on the Moon or Mars (e.g. web, Instagram, Twitter) due to the inherent light travel-time delay, and manage the unique SAM email addresses each team member will use, to which they will have forwarded their personal or work email prior to entering SAM. This is due to the fact that we cannot capture, store, and then release Gmail, Yahoo, or any other email but can introduce a time delay on a server that we control.

Wait. Did you say there is no internet on the Moon or Mars?! But how will I post to Instagram when I am take that first, bold step for all of human kind? How will I tell the world what I ate for breakfast? Where will I post the dozens of selfies my fans have been waiting for?! Surely, there is a way!

When Mars is near its closest point to the sun (perihelion) and Earth is at its farthest (aphelion), as the two planets were in 2003, there is 34.8 million miles (56 million km) between them. Earth and Mars are farthest apart when both are at their farthest from the sun, and at opposite sides of our host star, up to 250 million miles (401 million km) apart. SAM management will program the respective delay for each mission, from ~1.3 seconds for the Moon to 3 minutes one-way to Mars at its closest position and ~20 minutes one-way at its maximum.

While web (HTTP) and file transfers (FTP) have their own dedicated protocol, they all share something in common — the ability to send large files in smaller pieces, or packets. And with each of these packets is a checksum, a means of making certain that the packets arrived complete, without corruption due to a poor connection or cosmic ray strike, and ideally without having been hacked along the way. This means that each packet is prepared, and a mathematical value (checksum) assigned to the packet that represents the complete, unaltered data. When it is received, the checksum is compared to the contents of the packet, a response is generated and sent to the origin, and the next packet is sent. This is true for live video streaming, YouTube downloads, Instagram and Facebook posts, and direct file transfers from your computer to Google Drive or Dropbox, etc.

There are hundreds or thousands of packets sent every second, and if any one of these is stalled, even for a small fraction of a second, the entire system stalls too. The packets must be sent and received in order, or the photo or video gets completely scrambled (which we’ve all experienced). Therefore, even the relatively short distance to the Moon (~1.3 seconds) is too great a delay for one, let alone tens of millions of packets. And to Mars? Forget it. Under the current web protocol, there is simply no way.

So how did the Apollo astronauts send their live video broadcast? Analog radio signals that carried the video data were sent from their base to receiving antennae on Earth, and then rebroadcast to the world. Today, very few of these TV radio stations remain. Radio stations continue to broadcast analog signals with digital counterparts to improve the quality and provide information about the stations, newscast, or song.

“Broadcast” literally means “casting to the wide world” without concern for the receiving end. There is no means to guarantee that the information arrived safely. It’s just thrown out there, clear channel or encrypted, it’s a one-way delivery.

With our modern digital communications, your mobile phone or computer is conducting a private, secure, point-to-point dialog with a receiving station, and every packet MUST be accounted for, or the system stalls.

So how will we send data from the Moon or Mars?

Stay tuned …

By |2023-03-14T05:56:47+00:00January 7th, 2023|Categories: Research & Development|0 Comments

SIMOC-SAM Team Summit

Members of the SAM development team at Biosphere 2

(left to right) Anastasia Stepanova, Trent Tresch, Bindhu Oommen, Luna Powell, Atila Meszaros, Sean Gellenbeck, Kai Staats, and Colleen Cooley with Dr. Gene Giacomelli via the magic box. Jas Purewal of the Analog Astronaut Conference, Dr. Cameron Smith of Pacific Spaceflight, and Meridith Greythorne of the SIMOC team attended remotely.

Members of both the SIMOC and SAM teams met for a three days summit to design and develop the SAM visiting team experience. On Thursday, December 15 co-founder of CHaSE, the Center for Human Space Exploration at the Biosphere 2 Trent Tresch lead team members through the use of pressure suits and a crash course in the history of human space travel.

On Friday, December 16 the team met in the University of Arizona Center for Innovation (UACI) room at Biosphere 2 to develop a core philosophy around how visiting teams will be received and what they will take away from their experience at SAM. This effort was given foundation in an opening “safe space” visualization and discussion lead by Director of Research for SAM Kai Staats, followed by open discussion, ideation, and development of critical components of the SAM experience. Just after lunch the entire team participated in a pressure test of SAM, the first following the completion of the third pressure door by Nathan Schmit that very morning. Ezio Melotti, lead developer of SIMOC gave a demonstration of the latest version of SIMOC Live with real-time carbon dioxide, oxygen, temperature, relative humidity, and VOCs sensors, both Vernier and Adafruit products.

On Saturday, December 17 the team met for a final five hours to discuss the logistics for receiving SAM research teams to the Biosphere 2: training in conflict resolution, use of the SAM facilities, communication protocol and mission control, time in SAM, exit and debrief. The summit was captured in hand written notes and transcribed audio, and will be encoded into a comprehensive user guide for both the SAM team and visitors to this unique research facility in early 2023.

Notes and sketches were principally captured on a single roll of construction paper that stretched the length of the conference table, with pens, markers, and Crayons employed to express thoughts and capture ideas.

By |2022-12-23T04:25:53+00:00December 18th, 2022|Categories: Research & Development|0 Comments

UA Capstone team conducts baseline CO2 scrubber test

Grace, Brianna of the UA Engineering Capstone team conducting CO2 scrubber test at SAM, Biosphere 2

Joaquin, Grace, Kennith, Brianna, and Will of the UA Engineering Capstone team met with Trent Tresch at SAM on Saturday, April 9 to capture baseline performance data before the test of their own swing-bed CO2 scrubber design and scale, working prototype.

Trent lead the team in the effort to established a small, fixed volume of space in which both “the Paragon CO2 scrubber prototype designed for NASA’s Commercial Orbital Transportation System (COTS) program and the NASA-funded team’s prototype will be tested for their comparative ability to draw down CO2 from a given level over the period of 1 hour. The team employed a CO2 gas canister and delivery system, sealed tent, and three Vernier brand CO2 / relative humidity / temperature sensor (the later two variables used to internally calibrate for CO2).

This structure will remain in the SAM Test Module until the team can test their own design and then deliver the findings to NASA.

By |2022-04-14T05:12:02+00:00April 9th, 2022|Categories: Research & Development|0 Comments

University of Arizona Engineering Capstone team joins SAM!

We are pleased to welcome Brianna Otero, Grace Halferty, Joaquin Pesqueira, Kenneth Werrell, William Fowler to the SAM team for the next nine months. They will be working with Kai Staats, Trent Tresch, and John Adams at Biosphere 2 and Ara Arabyan and Douglas May of the University of Arizona to build a fully functional, scaled swing-bed CO2 scrubber. This project is funded by NASA through the M2M X-Hab Challenge.

By |2021-10-04T19:18:16+00:00August 31st, 2021|Categories: Research & Development|0 Comments

SAM Mars yard is under way!

SAM Mars Yard construction begins!

Construction of the half acre SAM Mars Yard begins with the removal of five original greenhouse structures used in the late 1980s to raise the plants ultimately placed inside of Biosphere 2. Laura Bryant and her team are removing the structures to be reused at her facility in Patagonia, Arizona where she specializes in organic foods for people with multiple sclerosis.

Once fully removed (it’s a big job!) our team will sculpt a first-draft layout with simple, earthen craters and simulated stream beds. Stay tuned!

By |2021-10-04T19:38:12+00:00August 1st, 2021|Categories: Research & Development|0 Comments

SAM Test Run data analysis

Sealed test of SAM Pressure baseline, June 29, 2021 Sealed test of SAM Temp, RH baseline, June 29, 2021 Sealed test of SAM CO2 baseline, June 29, 2021

Test Run Data Analysis

Test Run Timeline
4:02 pm – data START on External, Internal, and internal CO2 Scrubber sensors arrays
4:22 pm – seal Test Module
4:27 pm – blower START; pressure rise commences
4:32 pm – max pressure reached
4:36 pm – pan ring reaches approximately chest height, as viewed through the lower lung glass door
4:41 pm – blower STOP; pressure maintained by Test Module lung

8:02 pm – data auto-STOP
8:30 pm – open Test Module and release pressure—we were having too much fun and lost track of time 🙂

On Tuesday, June 29, 2021 the SAM development team conducted a fully sealed closure of the Test Module with 5 humans inside, for 4 hours. During this time the team maintained 3 sensor arrays to capture barometric pressure, carbon dioxide, oxygen, temperature, and relative humidity data.

  • External sensor array: Vernier LabQuest 3 with barometric pressure, O2 / temperature, and CO2 / temperature / relative humidity (RH) sensors. This array was placed outside the Test Module, near the entrance.
  • Internal sensor array: [identical to External] This array was placed inside the Test Module, near the entrance.
  • CO2 scrubber sensor array: Vernier LabQuest 3 with two CO2 / temperature / relative humidity (RH) sensor. This array was also placed inside the Test Module to compare the pre-scrubbed and post-scrubbed air. One CO2 sensor was secured at the inlet to the CO2 scrubber; the other inside the scrubber itself, in a chamber located just after the zeolite adsorb bed, before the exit filter and fan array.

Per the data plots (3 images at top) a baseline comparison of the External and Internal sensor arrays demonstrates that the units were behaving similar to each other before committing to the full 4-hours run. This baseline test was conducted in outside the Test Module, the units placed adjacent to each other. Minor variation in equivalency of the sensors is due to conducting the baseline in an uncontrolled (open air) environment and without post-factory calibration.

It is important to note the small variation in the data stream is the anticipated “noise” of any sensor, and that data sampling was principally conducted to validate the seal of the Test Module, not for peer reviewed publication of findings. Additional steps will be taken to further qualify the sensor array and associated data for future research and publications.

Sealed test of SAM Pressure data, June 29, 2021

Absolute Barometric Pressure
Following the baseline test (above), the Internal and Scrubber sensors arrays were reset and brought into the Test Module. The team consisting of Kai Staats, Trent Tresch, John Adams, Katie Morgan, and a writer entered the Test Module. The door was sealed and the blower activated as is indicated on the (above) plot by a rapid rise of the internal pressure. It took only a few minutes for the lung pan to rise from the floor, the higher pressure then retained for duration of the Test Run.

It is important to note that while the outside temperature dropped 4.2C and the internal temperature dropped 7.8C (a single, 2T mini-split heat pump is employed at this time) during the 4 hours run, the pressure invoked by the mass of the lung remains relatively constant once it is lifted from the floor. The lung pan lost ~50% of its original height due to temperature change but the pressure was constant until released. In future tests, the height of the lung pan will be monitored in real-time.

Calculating the Mass of the Lung
We can calculate the mass of the rigid lung pan using its radius of 10 feet. While the membrane’s tapered surface and flexible function makes for a constantly changing shape, we can treat it’s lift body as the surface area of a horizontal cross-section from lower lung pan ring to upper lung ring, both of which provide the membrane seal. We’ll add another 3 feet to the radius to account for the membrane, for 13 foot total radius, or 26 foot diameter.

We find the cross-section area of the pan and membrane to be:

Pi x (13’r)^2
x 144 square inches (in^2) per square foot
= 76,454 in^2 total surface area

The mass of the pan is exerting a force on the column of air (measured per square inch) that resides below in addition to the ambient atmospheric pressure. As this body of pressurized air is connected to the Test Module’s interior via the tube, the result is an increase in interior barometric pressure of the Test Module. As we recorded a 0.05 PSI (0.345 KPa) increase in internal atmospheric pressure due to the inflation of the lung and subsequent lifting of the lung pan and membrane:

76,454 in^2 x 0.05 psi = 3,822 lbs
– or –
49.325 m^2 x 0.345 kpa x 101.9 kg per square meter = 1,734 kg

We therefore estimate the metal lung pan and membrane to have a mass of 1,734 kg, or a weight of 3,822 lbs. When we return to SAM in September, we will place a scale beneath each of its six legs and learn how close we came in our calculations.

Sealed test of SAM Temp, RH data, June 29, 2021

Relative Humidity, Temperature
As anticipated, the Relative Humidity increased as the Temperature dropped internal to the Test Module. While we did not employ an absolute humidity monitor, it is likely absolute humidity increased as well, given five humans exhaling for four hours. The temperature internal to the Test Module dropped more significantly (-7.8C) than outside (-4.2C) given the mini-split cooling which is more efficient once the sun is no longer directly heating the Test Module.

Sealed test of SAM CO2 data, June 29, 2021

Carbon Dioxide
The CO2 data are perhaps the most interesting to our team. Analysis of the data match our understanding of the Test Module system and its inhabitants to a working degree. Future, controlled tests of sub-systems will improve our ability to model this working vessel as we integrate it into the agent-based model SIMOC.

Per the plot above, there are two sensors in the Test Module interior: CO2 Hab Int (red) and CO2 Scrub Ext (yellow). As noted at the top of this article, CO2 Scrub Ext is external to the CO2 scrubber but internal to the Test Module itself. The data shows they rise in parallel for the duration of the run. Why are they not identical? As demonstrated in the Baseline test, this is likely due to their default calibration and/or variations in CO2 concentrations for even within a single volume there are pools and eddies of air that contain varying densities and partial pressures of component gases. This is well understood and intentionally mitigated with large fans in the Biosphere 2 rain forest biome today.

Clearly, the external CO2 remains constant while the internal CO2 increases as soon as the five team members enter due to human respiration. If we compare the external CO2 baseline to the highest point internal to the Test Module, we see an approximate 1200 increase to just under 1600 parts per million. This is roughly 60 ppm per person per hour. In a future update to this article we’ll compare the average CO2 production for a human at rest against the total volume of the Test Module and Lung interiors to determine if our five team members were high, low, or average.

The CO2 Scrubber
The CO2 Scrub Int (green) sensor was placed inside a sealed chamber such that no air flow was enabled across the zeolites nor through the total CO2 scrubber chamber until two louvers were lifted and the fans engaged. When Trent placed the CO2 sensor inside he was breathing directly into the chamber, thereby artificially elevating and then sealing the enriched air inside. The slow decline over four hours representative of a quality, yet understandably imperfect chamber seal.

As soon as the fans were activated (minute 209) and internal Test Module air was drawn into the scrubber, the CO2 level in that interior chamber rose dramatically, as it should. The function of the zeolites is demonstrated by the flattening of the CO2 levels in the subsequent data points until the run is complete. The small bump at minute 228 is due to a switch from fan #1 to fan #3 with a total increase in airflow. Clearly, this does not equate to an increase in adsorption by the zeolites thereby indicating the airflow likely surpasses the adsorption rate of the given volume of zeolites.

The CO2 scrubber provided by Paragon Space Development Corporation was designed to remove CO2 for 1-7 persons in a volume of air much smaller than the Test Module. While the amount of CO2 generated by a human remains constant independent of the size of the vessel in which they reside, given a larger volume vessel a larger volume of air must be processed to capture the same amount of CO2 over a given period of time. Given this initial run, it appears the current volume of sorbent coupled with the volume of air being processed was able to mitigate but not immediately reduce the CO2 within the Test Module. It is possible that given a longer duration run the scrubber would catch up and manage accordingly, or more likely that the scrubber will need to contain a larger volume of sorbent.

In Closing
It was our intent to complete the redesign of the scrubber to include a desorb function (CO2 release by means of heat and a partial vacuum) by the close of Phase I development at SAM. We were unable to complete this in time for this Test Run, but we did reduce the volume of sorbent contained within the scrubber to minimize the scope of the test medium. However, this also reduced the total volume of sorbent to 64% of its original capacity. If we were to do this again, we’d have simply switched from soda lime to zeolites and retained the full, original capacity of the Paragon scrubber until we move into Phase II at SAM with additional resources and time for experimentation.

Future, controlled tests will refine our understanding of this unit, the use of zeolites, and how best to implement this physico-chemical CO2 mitigation agent in our fully constructed SAM crew living space, adjacent to the Test Module.

As noted at top, we did employ O2 sensors but are honestly confused by the data. We’ll return to this article with an update as we come to a better understanding.

Test Module Dry Run | Five Persons Sealed Inside | Data Analysis

By |2022-02-05T05:36:35+00:00July 4th, 2021|Categories: Research & Development|0 Comments

Biosphere 2 Deputy Director John Adams conducts pressure suit test at SAM

Biosphere 2 Deputy Director John Adams conduct pressure suit test at SAM

A decade ago archaeologist at Portland State Dr. Cameron Smith redirected his knowledge and passion for human history toward the future of our species as we become interplanetary. His academic publications and books project a social—even biological evolution as we move to the planets and stars.

Suit sketches by Cameron Smith Cameron launched Pacific Spaceflight (PSF) to explore design, construction, and validation of low-cost, fully functional pressure suits that enable every-day citizens to reach the edge of space and beyond. These personal spacecraft are a critical aspect of off-world exploration, no matter if you are at 65,000 feet above sea level, on-orbit, or on the Moon or Mars. More than a novelty, PSF suits have been tested under water, in vacuum chambers, in the open cockpit of aircraft and in high altitude balloon projects. Cameron’s dynamic team of volunteers (including Kai Staats and Trent Tresch of a Space Analog for the Moon and Mars (SAM)) have both contributed to and been influenced by his critical work.

John Adams in a pressure suit, SAM at Biosphere 2 On Tuesday, March 2, at 7:00 am John Adams, Deputy Director of the University of Arizona Biosphere 2 engaged in the other-world journey of donning a pressure suit to conduct a number of tests for mobility and tool use, both of which can be challenging when encumbered by a sealed suit under greater than ambient pressure.

This endeavor was conducted inside and around the historic Biosphere 2 Test Module, now five weeks into a major refurbish and construction endeavor as the cornerstone of SAM. This event was a fully immersed operational test of the equipment, suit, and procedures which SAM researchers will enjoy when a part of this analog experience. SAM has purchased two suits from Smith Aerospace Garments that will be available for team members to use in the half acre SAM Mars yard just outside of the living quarters and Test Module.

The specs for this particular pressure suit are as follows:

  • Suit model: Pacific Spaceflight, experimental Mk SE I (2018-2019)
  • Suit construction: sealed bladder with high-durability outer garment; attached boots and gloves with removable helmet
  • Air composition: standard mix of ~78/21% nitrogen/oxygen levels
  • Pressure inside the suit: ~1.0 psi over ambient
  • Suit pressure max spec: 3.5 psi over ambient
  • Compressed air source: dual feed, oil-free air compressor with 4 gallon reserve

Cameron engaged John in the suit-up procedure for approximately 30 minutes (full photo gallery below). At this time the air compressor inside the Test Module simultaneously fed John’s suit directly and a manifold that enables controlled gas exchange to the outside world. Of his own accord he opened the bulkhead door and proceeded outside. There, his feed line was switched to the manifold exterior. The momentary break from his air source was possible due to the suit acting as a short-duration buffer. SAM teams will carry a small, portable compressed air source that will provide continuous flow as feed lines are swapped from airlock to the hab exterior.

With the assistance of Cameron and Trent, John conducted a basic walk, followed by tool use, ladder climb, CO2 level check, and ascent of the exterior of the Test Module lung. This prototype suit was designed for mobility, but has been surpassed by the current models which will be delivered to SAM by late spring 2021.

In conclusion John shared, “The suit is amazing! I feel really good … all things considered, you still have quite a bit of dexterity, quite a bit of ability to lift your legs, to move around complex objects. To have an opportunity to experience a pressurized suit in a simulation setting is incredible. I feel really fortunate to have this opportunity.”

We extend our thanks to the University of Arizona’s Aaron Bugaj for exceptional photography, Katie Morgan for work with social media, and Megan Russell and Britney Swiniuch for your support and enthusiasm for this first-ever pressure suit test at SAM.

By |2021-04-27T16:57:58+00:00March 4th, 2021|Categories: Research & Development|0 Comments
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