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SAM Construction – Summer Break

SAM at Biosphere 2

It is our pleasure to bring to a close Phase I development and construction of a Space Analog for the Moon and Mars (SAM) at Biosphere 2. This past six months of research, design, engineering, and hands-on construction has been a tremendous labor of passion by Kai Staats, Trent Tresch, Biosphere 2 Deputy Director John Adams, Tim Mcmullen and Terry Murchek of Biosphere 2’s maintenance staff, intern Natasha Loving, and our volunteers Cameron Smith, KC Shasteen and Michael Blum, Linnaea Groh and Atila Meszaros, Robert David and Angus Gluck, Colleen Cooley, Trenton Kenney, and Jolene Varga and Rob Ronci.

We thank Executive Director Joaquin Ruiz and Deputy Director of Research Cherry Murray and the whole of the Biosphere 2 staff for continued, daily support; Murat Kacira and Gene Giacomelli of the University of Arizona Controlled Environment Agriculture Center; and Doug Hocksteed and Rakhi Gibbons of TechLaunch Arizona for the initial round of funding. Jude Yandow was instrumental in keeping the finances in order and Julie Stringer for helping us navigate the complex framework of the University.

We look forward to returning in September to dive back into SAM construction, with the first of three shipping containers already in place for the 1200 sq-ft crew living quarters.

See you then!

By |2021-07-20T20:47:48+00:00July 5th, 2021|Categories: Construction|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 reporter Jessica Aguirre 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 |2021-07-08T17:16:58+00:00July 4th, 2021|Categories: Research & Development|0 Comments

5 person crew sealed inside SAM for 4 hours!

Trent, Katie, John, Jessica, Kai in the first full seal of the Test Module at SAM, Biosphere 2

We did it! We completed the first seal of the fully refurbished Test Module at Biosphere 2! The experience was extraordinary, a true celebration of the effort to bring this iconic prototype pressure vessel back to life!

The day started with long-time B2 electrician Kevin installing a new 100A, 3-phase disconnect in our primary panel at SAM. Then Chris Kaufmann, Brian Scott, Neal Barto, Emma Menden, and Michael Mason from University of Arizona CEAC delivered, assembled, and transplanted a full suite of food cultivars (some 180 in all), the first to arrive to SAM. Trent moved the CO2 scrubber into place while John and Kai established a base-line for the sensor array, both internal to and external to the sealed Test Module. Leonardo Buono, a veteran filmmaker was on-site for the entire day to both film and manage the lung inflation fan and valve.

With a few words spoken prior to entry, the crew walked inside and sealed the door.

Kai Staats, Trent Tresch, John Adams, Katie Morgan, and reporter Jessica Camille Aguirre were sealed inside for four and a quarter hours. While monitoring the CO2, O2, temperature, relative humidity, and barometric pressure, they played Xtranaut, a board game developed by Dr. Dante Lauretta at the University of Arizona, Principal Investigator for OSIRIS-REx, the spacecraft that is returning a sample from the carbonaceous asteroid Bennu. Finally, this first team to enter the fully refurbished Test Module assembled a FarmBot, an open source precision agriculture CNC farming tool. Our unit was donated to SAM by founder Rory Aronson. It is beautifully constructed, an elegant machine we are eager to employ later this year.

This marks the first time in 30 years that humans have been sealed inside the Test Module and the completion of Phase I construction of SAM, a Space Analog for the Moon and Mars at Biosphere 2.

We were honored to have colleagues and family waiting outside SAM for the duration of the test run, greeting us as we exited at 8:30 pm with a bottle of bubbly and lemonade. Thank you for your support, and for keeping Leo company!

Now, we have data to analyze, photos and video to process, and six months of work to bring to a close.

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

By |2021-07-08T17:15:50+00:00June 30th, 2021|Categories: Construction|0 Comments

The Test Module is sealed for the first time in 30 years!

Following six months demolition, construction, and revitalization of the prototype for the Biosphere 2, the Test Module is sealed and pressurized for the first time in 30 years! Kai Staats, Trent Tresch, and Biosphere 2 Deputy Director John Adams discuss this important endeavor and then activate the blower which causes the lung to inflate and the massive pan to rise, providing a hermetically sealed space within the Test Module.

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

By |2021-07-08T17:16:18+00:00June 29th, 2021|Categories: Construction|0 Comments

Saying farewell to SAM volunteers

SAM team and B2 staff at SAM, Biosphere 2

Yesterday we said goodbye to volunteers Jolene Varga and Rob Ronci (far left) from Colorado. They lived on the Biosphere 2 campus and worked with us at SAM for a full week. Thank you for jumping into the fire of the final week before pressure tests!

We also bid safe farewell to Trenton Kenney (back row, between Rob and Kai) from the University of Minnesota. “Kenney” was with us for three weeks and worked on just about every aspect of the project. We’ll miss your incredible cooking, fun anecdotes, and updates from the halls of NASA. But thank goodness my First Aid kit will no longer be used a few times each day!

Natasha Loving (front left, red shirt) is with the University of Arizona and provided her second week of volunteer work at SAM (Thr/Fri). She will be working with us over the summer, receiving credit for her work at SAM. Thank you for your diving into every project handed to you, and for singing while you worked as your voice echoed up into the Test Module—it was quite relaxing.

(SAM developers Trent Tresch and Kai Staats are in beige and black shirts, respectively)

Katie, Brittany, and John (right side) of the Biosphere 2 management and research staff, your support and enthusiasm for this project continues to be imperative to our success—thank you!

By |2021-06-30T05:28:23+00:00June 27th, 2021|Categories: Construction, Visitors to SAM|0 Comments

The Sounds of SAM

A variety of audio recordings captured during the six months endeavor to restore pressurized functionality to the 1987 Test Module, prototype for the Biosphere 2 and cornerstone to the Space Analog for the Moon and Mars, SAM.

By |2021-07-04T05:21:21+00:00June 26th, 2021|Categories: Videos|0 Comments

SAM Construction – Resealing the Test Module Lung

Test Module at Biosphere 2

Diagram of the Test Module and Lung, circa 1987

The Test Module lung was developed as a “method of managing the effects an internal temperature and external barometric pressure change could cause in a fixed, sealed, glass structure. This problem was solved with a variable volume system joined to the module by an air duct. With increased temperature or decreased barometric pressure in the Test Module compared to the out- side environment, the variable chamber expands; with a decrease in temperature or a increase in pressure, the chamber contracts. The lung structure provides an effective means to prevent the possibility that the Test Module would implode or explode when subjected to these forces. The reservoir of air provided an increased buffering; adding approximately 20-40% to the total atmospheric volume. The weight of the pan on the lung structure insured a positive displacement from inside the closed system to the outside.” — Abigail Alling, Linda Leigh, Taber MacCallum, and Norberto Alvarez-Romo. Biosphere 2 test module experimentation program. Biological Life Support Systems 23 (1990): 32.

This week was the last, big push for resealing the Test Module and lung—dozens of small details and a few substantial undertakings before our first pressure tests on Monday.

There are 18 points at which the Test Module pressure vessel is penetrated, including the entrance and a 7-port gas exchange manifold. In the 1987-89 test runs these served various purposes: monitoring the internal air and water (drinking, waste, marsh); moving sensor data over physical cables; exchanging hot and cold water for the heat exchanger then mounted in the overhead space frame. The clean water inlet will be reainted, but used sparingly (everything that goes in, stays in). The 3″ diameter copper feeds for the heat exchanger are terminated and capped. Since the ’80s much has changed in data transmission. Now a single wireless feed can readily transmit a vast quantity of real-time data and video. However, two hard line connections (Ethernet, USB) will be installed in order to rebuild or update computers and embedded devices (e.g. WiFi router), and as a back up should the wireless go down.

As such, we have reduced the number of ports to:

  • A fresh water inlet
  • Wired data (Ethernet + USB)
  • Electrical feeds from the external, primary panel to the internal sub-panel
  • Continued use of the original, 7-port gas exchange manifold
  • Two new manifolds for the mini-split heat pumps (coolant, power)

The lung is an adjacent structure connected to the Test Module by means of a 100 cubic foot, underground corridor (tube) large enough to crawl through. The lung is composed of a concrete structural frame and welded steel, cylindrical wall and floor. The upper lip of the cylinder is sealed to the larger end of the flexible rubber membrane (not unlike the rubber used on inflatable river rafts) from which is suspended a 22 foot diameter steel pan which itself is attached to the lower end of the membrane, and re-sealed (per our effort today). The area above the pan is open to the outside air. The area below the pan is an extension of the Test Module volume itself, with air movement through the restricted corridor.

The lung also has more than 20 penetrations. All but five were capped or plugged. As with the Test Module, all unused ports in the lung are sealed with Teflon tape over threaded plugs or caps.

As such, the functional ports are:

  • A single feed gas manifold (may or may not be retained)
  • Lung inflation fan with 3″ ball valve
  • Electrical feed to lights
  • Water column pressure release “P” trap

The inflated lung provides a positive pressure internal to the living space, an automated compensation for both internal temperature changes and external barometric pressure changes, and a buffer such that for the duration of a simulation, a hermetic seal may be maintained. The better the total seal, the longer a simulation can run without adding outside air.

When the Test Module and lung were inspected in the fall of 2020, it was clear that a great deal of work would be needed to regain a fully sealed function. The curved steel ring segments that held the rubber membrane in place were completely rusted from thirty years of water and weather, to the point that many of the threaded rods simply snapped off or turned to dust in one’s fingers.

Kai, Trent, and a host of volunteers have worked on various aspects of lung repair since January ’21, focused on patching the membrane itself, restoring the surface of the lower ring, welding 220 new threaded rods (studs), sealing against further rust, and then, finally, restoring the seal with a new set of individual 4″ stainless steel plates, replacing the nine heavily rusted angle iron rings segments. Furthermore, the outer shell of the lung has been completely sealed with silicone caulk and a 100% elastomeric such that only in the worst storms might a small amount of wind driven rain find its way onto the upper, external facing side of the membrane.

As of the posting of this photo essay, the silicone is a half dozen hours into a 72 hours cure. We are confident that we have a solid seal between the membrane and the lower ring of the steel pan. With the lower lung door rebuilt and ready to be installed there are no known open ports or holes in the entire pressure vessel. However, we remain aware that one or more holes may exist and that no system is fully sealed.

Our fingers are crossed for success in pressurizing the Test Module for the first time in thirty years!

Stay tuned!

By |2021-07-05T20:43:20+00:00June 25th, 2021|Categories: Construction|0 Comments

SAM Construction – Dry run of the Test Module Lung a success!

Dry test of lung inflation a success! SAM at Biosphere 2 Dry test of lung inflation a success! SAM at Biosphere 2 Dry test of lung inflation a success! SAM at Biosphere 2

The Test Module lung was developed as a “method of managing the effects an internal temperature and external barometric pressure change could cause in a fixed, sealed, glass structure. This problem was solved with a variable volume system joined to the module by an air duct. With increased temperature or decreased barometric pressure in the Test Module compared to the out- side environment, the variable chamber expands; with a decrease in temperature or a increase in pressure, the chamber contracts. The lung structure provides an effective means to prevent the possibility that the Test Module would implode or explode when subjected to these forces. The reservoir of air provided an increased buffering; adding approximately 20-40% to the total atmospheric volume. The weight of the pan on the lung structure insured a positive displacement from inside the closed system to the outside.” — Abigail Alling, Linda Leigh, Taber MacCallum, and Norberto Alvarez-Romo. Biosphere 2 test module experimentation program. Biological Life Support Systems 23 (1990): 32.

The “lung” is a pressure regulation and air storage system first tested 33 years ago as part of the Test Module program. It was then improved upon and scaled to a much larger volume for the Biosphere 2 proper. Today Trent Tresch and volunteer Rob Ronci of Colorado were successful in conducting a dry run inflation of the refurbished Test Module lung.

With the lower lung door only partially sealed, the electrical sub-panel ports not yet complete, and one known leak in the Test Module space frame structure, the lung membrane inflated and rose to an inverted position in just a few minutes of running the inflation fan.

This bodes well for what we believe will be a fully functional test of the lung early next week.

Trent Tresch, Rob Ronci preparing dry-run inflation of the lung at SAM, Biosphere 2 Rob Ronci preparing dry-run inflation of the lung at SAM, Biosphere 2

By |2021-07-05T20:43:59+00:00June 24th, 2021|Categories: Construction|0 Comments

SAM Construction – A race to the finish!

Trent Tresch, Sean Gellenbeck install a new inflation system for SAM at Biosphere 2

We are just ten days from the conclusion of Phase I of construction of SAM, and a week from the start of a series of pressurized tests in which we will monitor temperature, humidity, CO2, O2, and both interior and exterior atmospheric pressures as we seal the Test Module for varied durations of time.

June 20 also marks five months labor at the SAM analog site, from the early efforts in pushing back the desert growth to stripping the Test Module interior down to the frame and grinding, sanding, and cleaning the lung pan, ring, and membrane. In putting it all together again we have primed and painted, welded and wired, shoveled, cut, caulked, sealed, glued and cemented from sunrise to sunset, four to five days a week since January 20.

This kind of adventure may not take its participants across high seas or through dense jungles, but the arduous effort is rewarding in a similar manner. A passion for achieving difficult goals, attention to detail, problem solving, and working within a highly capable, agile team. Our race to the finish is not one of competition with others, but one of upholding a pledge to ourselves, partners, and investor Tech Launch Arizona that we will by the close of the University of Arizona fiscal year refurbish and revive the 1987 Biosphere 2 prototype Test Module as the cornerstone of SAM.

This is our list of actions items that remain, with one week to complete them all:

  • Install two 2 ton mini-split heat pumps (air conditioning).
  • Complete reconstruction of the sealed, lower lung door.
  • Apply the remaining patches to the lung membrane.
  • Patch the one known exterior break in the original silicone sealant.
  • Run electrical power from the exterior 100A service to the sub-panel; then
  • Build-out four electrical 120V sockets for interior use; and
  • Wire the overheads lights to a switch.
  • Fully bleach and scrub the lung interior.
  • Install the interior manual pressure release valve.
  • Conduct a dry pressure test before re-attaching the lung membrane to the ring.

Thank you Sean Gellenbeck, aerospace engineer at Paragon Space Development Corporation and PhD student at the University of Arizona for stopping by SAM and lending an expert hand! Your experience with varied materials and rapid development was well received!

By |2021-06-27T01:39:49+00:00June 21st, 2021|Categories: Construction|0 Comments

LPI Terrestrial Analogs for Planetary Exploration

LPI Terrestrial Analogs Workshop 2021

June 16–18, 2021

The USGS Astrogeology Science Center is hosted a virtual Workshop on Terrestrial Analogs for Planetary Exploration. The workshop brought together community members to discuss a wide range of scientific investigations of planetary analog terrains and processes, exploration strategies, and orbit-to-ground comparisons. Abstracts wre solicited for topics including various planetary processes (volcanic, impact, aeolian, subaqueous, mass-wasting, glacial, tectonic, and others) as well as geophysical, geochemical, and astrobiological investigations. Discussions of field methods, sampling techniques, exploration strategies, technology applications, and ground-truthing were covered, and topics related to data standardization and dissemination. In addition, the workshop addressed analog work that will benefit human and robotic exploration of other planetary surfaces.

Kai Staats provided the closing talk of the day, an overview of the Scalable Analog for the Moon and Mars, SAM.

Workshop Home Page | Workshop Program | SAM Abstract

By |2021-06-19T20:12:57+00:00June 19th, 2021|Categories: Publications|0 Comments