Construction

Project management is a complex endeavor. Finding the right balance of give and take, guidance and learning is imperative for the long-term health and success of a team as diligently involved as that which is constructing SAM.

When Luna ventured to the cafe in Oracle before departing for an early weekend, John, Bindhu, and Kai found themselves in the challenging situation of having an extra pastry. This is one of those moments in which a team could be catapulted into the kind of grievance and mistrust from which it may never recover, or move through the situation with grace, stronger than ever.

We approached this with the same engineering precision applied to the fabrication of SAM, and the outcome was completely satisfactory.

This past week has seen tearing things apart more than putting them together, which feels like progress lost even when we know it is the best way forward. In order to weld the perimeter of the end of the 20′ container we had to remove the west-end insulation panels installed this summer—two days of effort undone in a few hours. We learned how well the construction adhesive adhered and the properties of expansion foam in small and large spaces. What’s more, we cut channels in the side walls in order to visually see (and later test) the quality of the weld by exposing the seam on the inside for our auditory and visual inspection during consecutive pressure tests.

Between the Tuesday, November 1 and Friday when UA welders Charlie and Chad were onsite, we filled our days with myriad small projects, the kind otherwise left for when major efforts are complete. It was hard to focus, at first, but in looking back it feels good to have checked-off so many tasks.

• Cleaned the conduit from the TM to the site of the original, external data terminal.
• Removed the 2021 lung patches with heat gun and careful application of pressure.
• Installed the insulating ceiling panels to the SAM Air Intake Room (AIR).
• Chipped the entrance to the TM-to-lung tunnel in prep for primer.
• Removed the TM outer (non-sealed) door and hinges; sanded, primed.
• Scraped, sanded, and primed the final, inner segments of the lung pan.

In a project such as this, there are moments no one will forget. One such moment was when we decided to reverse the flow of air in the shop-vac and blow any debris out of the two PVC conduits we retained that once carried power and data from the TM to the computer terminal and data analysis terminal. We were horrified and at the same time overtaken by laughter when not only did a cloud of dirt, seeds, droppings, sticks and twigs fly into the air, but a mummified rat too!

We realized then we had to clean these pipes well beyond simply blowing air. We repeatedly filled them with water and bleach and using the vacuum in reverse, created a water fountain until it ran clean (banner at top). The words “Disgusting!” and “Oh no! That is really gross” were heard over and over followed by “Let’s do it again!”

With our second full week back at SAM we remain focused on sealing and pressure testing, with some landscaping of the desert immediately surrounding SAM after a summer of intense rain and immense growth. We welcome Ezio Melotti, lead developer of the SIMOC project, and the return of Anastasia Stepanova, former engineer for the SIRIUS analog in Moscow, now PhD student at the Colorado School of Mines and SAM team member.

In preparation for this third pressure test of the expanded SAM vessel, we applied a proper fill of Dow-Corning 795 silicone in the window channels, providing the needed wider, deeper seal. We activated the lung blower in the SAM Air Intake Room (AIR) and as with the prior test the lung rose and the pressure increased.

Using the technique described by William Dempster and Linda Leigh, we lit incense and moved slowly through SAM, module to module, interface to interface and sure enough! —we were able to visually confirm the leaks we could hear, and discover a few more too.

Through this test run it became clear that the plates that cover the end of the 20′ shipping container will need to be welded for the complex assembly of steel stud framing was not something we could satisfy with 795 alone, especially if we desired to apply something more than a finger bead to those critical areas.

Before deflating the lung, Ezio notified Kai (via radio) of a previously unnoticed hissing sound. Kai entered the lung from the TM (through the tunnel) and discovered that roughly half of the patches applied to the holes in the original membrane were compromised—dried and cracked in just a little more than a year. This was completely unexpected, but perhaps a known function of siliconized rubber that was overlooked. Kai, John, and Luna have subsequently, carefully removed the old patches with new EPDM material (similar to the original membrane) on its way to Biosphere 2.

What’s truly incredible is that the lung rose at all given the number of holes in the membrane in addition to the known leaks in the TM, 20′ and 40′ shipping container. This gives us great confidence in our ability to maintain pressure for long periods of time, days, possibly weeks once all leaks are properly managed.

The UA welders will arrive on Tuesday to complete seals of two more interfaces, and then we’ll be back in the running for another pressure test and continued construction. Stay tuned!

In preparation for our first pressure test of the expanded SAM vessel, we applied a thin fill of Dow-Corning 795 silicone to the channels where two original Test Module windows were replaced by a single steel hatch plate in late 2021, just enough to hold a temporary seal. 795 is an incredible product, remaining flexible after 35 years (even in external Arizona applications).

It is our intent to apply the method used by the Biospherians. While 795 provides a flexible, long-lasting seal, it is gas permeable. While a shallow seal will hold pressure immediately, it will leak more gas than a deeper seal, over time. Therefore we will ultimately apply a silicone bead approximately 3/4″ wide and 3/4″ deep for the given pressure differential.

After synchronizing the Vernier barometric pressure sensor and two cell phones with barometric sensors, all three of which register to one one-hundredth of a PSI (0.0n), and set the timer, Ezio and Kai remained outside while John and Luna were sealed within. We activated the lung blower in the SAM Air Intake Room (AIR), the lung rose, and … we could hear all kinds of leaks across the TM, 20′ and 40′ shipping containers! Most of these leaks were anticipated, some new and unexpected. It was an exciting event from start to finish. John and Luna marked leak points with blue painters tape while Kai recorded leak points with a camera on the outside. The test ran roughly one hour and twenty minutes, start to finish, and was a complete success given the function of the lung and what was learned.

We recorded a barometric pressure baseline, the start of the blower, rise in pressure, maximum pressure achieve when the lung plate lifted from the floor, and the gradual drop of the lung plate and pressure when it again sets down. We achieved roughly 50% of the desired 0.1 PSI increase in pressure, as calculated in our June 2021 pressure test.

John and Luna patched a number of holes and ran a second test the following day. The third test was run following the Mars Society conference.

With the daytime temperatures quite comfortable and the SAM team fully recovered from the last construction sprint, we are back to SAM with a singular focus — achieve a hermetic seal and hold an internal, positive pressure for as long as possible.

To this end, every sheet metal screw that extends from inside to out is backed out of its threads, coated with 795 silicon, and seated again. All temporary silicon finger beads will be replaced with silicon channels or welding to minimize the gas transmission over time. The final rows of insulation in the 20′ shipping container (SAM workshop) are being completed, a job unfinished from the final days of our effort in July.

This is the best part of a multi-year endeavor, when the team has worked together through thick and thin, through snowfall and in the blazing sun, success, failures, and everything in between—all project segments that lie ahead are well defined and each week we feel we are making progress toward the goal of providing a hi-fidelity research vessel for visiting, research teams.

We are eager to conduct our first pressure test since June 29, 2021!

John Z., Luna Powell, and Kai Staats have arrived to Biosphere 2 for a final three months construction sprint, working sunrise to sunset (and then some) to complete this high fidelity Mars habitat research station at Biosphere 2. We have until the close of 2022 to complete fabrication and testing of the expanded pressurized vessel, electrical wiring, plumbing, and interior layout with January for extended testing and fine-tuning of systems and procedures before receiving first teams in 2023.

We look forward to returning team members Atila Meszaros, Sean Gellenbeck, Anastasia Stepanova, and Grant Hawkins, and new additions Ezio Melotti, Bindhu Oommen and Nathan Schmit.

Stay tuned for photos, stories, and data!

As we are constructing SAM from three exiting structures (the original Biosphere 2 Test Module (TM), a 20′ and a 40′ shipping container) no two interfaces between these units is identical. Rather, each is an experiment in design where the corridor must be ridged to support the weight of a human passing inside, protected from the elements so as not to rust or degrade over time, and attached on both ends so as to maintain a pressurized seal between dissimilar materials.

We learned a great deal in the study of the TM. The 5’x5′ windows are held in a steel frame which itself it bolted to the TM. A 3/4 inch channel between the inside of the window frames and the steel frame of the TM is filled with 795 silicon to provide a pressure seal and low-permeability gas release over time. This system has remained untouched for more than 30 years and remains 100% sealed, even flexible to the touch. It was our intent to duplicate this method for all interfaces, however, we determined that the effort would result in more welding overall than simply welding the interfaces themselves.

As such, we asked James Parker, Supervisor of the University of Arizona Metal Shop to let us know when his team could give us a full day at SAM. On August 18 Charlie and Steven applied their expertise, successfully welding the side walls, tops and bottoms of the corridor between the Test Module and 20′ container, and between the 20′ and 40′ containers. Kai removed the insulation from the exterior prior to the welding team arrival, and when complete (and cool to the touch) applied a coat of primer to the exposed areas, then replaced the insulation sheets.

And with the close of June, first week of July already come and gone, we are departing Biosphere 2 for our second summer, returning in early October to initiate the final three months of SAM construction, conduct pressure tests, and prepare for our first team arrivals in early 2023.

See you then!

With the final three weeks of work at SAM, John Z., Luna, and Kai completed many small projects, wrapping up loose ends to the second, entering third phase of construction. Luna replaced more than 300 original nuts and washers that hold the sealed windows in place with stainless. The skylight mounted as the bathroom window was temporarily removed to apply a generous layer of Dow-Corning 795 silicone (the same used on the Test Module and Biosphere 2) and reset. The variety of tomatoes grown inside the Test Module for the Analog Astronaut Conference produced delicious fruit, were consumed, the plants composted. Several afternoons were spent loading aluminum stays and struts, scrap metal from the roof panel installation for delivery to the roll-off metal recycling bin behind the B2 Energy Center.

For a sum of three weeks John Z., Luna, Kai, and Sean insulated the 20 foot shipping container which will serve as the workshop for SAM. The panels were provided by InsoFast, a low VOC product specifically manufactured for a given shape of container (thank you Angus for the recommendation). While the installation video showed professionals completing a 20′ container in 12.5 minutes, we required something closer to 12.5 days (maybe a bit more). It’s tedious, exacting work but in the end, a good solution. The built-in “studs” provide support for 500 lbs and provide a high “R” value and moisture barrier of close-cell foam.

MrCool manufactures an innovative, do-it-yourself mini-split heat pump—an air conditioning unit with both the condenser and lines pre-pressurized with coolant. It really is quite clever and relatively simple to install, requiring only two crescent wrenches, two screw drivers, hole saw, PVC tape, and some careful planning. We probably spent as much time in measurements as in the actual hands-on effort, which paid off. Given that SAM is not your normal house, we were very careful to consider how we would maintain the hermetic seal given the need to cut a hole through the wall of the insulated 40 foot shipping container. Our solution was simple: we placed a patch of PVC tape over the hole which houses the pressurized lines and electrical line for the air handler, and cut an “X” incision to push each line through with minimal exposure. From the outside we re-filled the space between the interior stainless steel, and exterior aluminum skin with spray foam that pressed against the PVC tape, expanding to the outside again. Now, spray foam is bonded to spray foam in that insulated cavity and we hope, sealed. The outside of the hole is covered by a water tight electrical box leading to the insulated, pressurized coolant lines for maximum thermal retention.

For now, the unit runs off an extension cord (measured 7A, max 11A at 110V) and will be properly hard-wired once we run additional lines from the main feed. Within thirty minutes the Crew Quarters was a cool 78F compared to the 100F+ outside. It works! And we are set for the summer.

Two years ago this summer the SAM development team met via Zoom to discuss the best way forward for the Space Analog for the Moon & Mars. At that time, it had been our intent to move the Test Module, piece by piece, from its original location to the north yard of the Biosphere 2. This difficult task was, at that time, intended to give maximum exposure to SAM as it would be directly on the tourist walking path and in the shadow of Biosphere 2 proper.

However, through conversations with individuals at NASA we were reminded that for long-term missions isolation from tourists would be ideal, off the main campus with minimal disturbance. Furthermore, we could drastically reduce the cost of construction by leaving the Test Module on its original, sealed foundation. Once we changed that mindset, it opened a whole new way of embracing the project. And as is often the case, we saw what was right in front of us as something wholly beneficial with incredible potential.

When Biosphere 2 was opened in 1991, the visitor center and parking was above the Test Module. Tourists walked past the Test Module and a half acre botanical garden complete with working simulations of the biomes inside of B2. In this manner, tourists could experience some of the interior environment and learn about the analog experience without being sealed inside.

Last summer we removed five greenhouse structures to make way for our exterior Mars yard, a space that will be reconfigured for long-duration teams and for rover competitions. We retained the 6,400 square foot rain forest greenhouse with intent to replace the former plastic panel roof with corrugated, galvanized steel. In March we removed the remaining plastic panels (most had fallen to ruin after thirty plus years) along with a massive amount of aluminum framing, steel cables, and no-longer-in-use electrical components. Just two weeks ago we rented a scissor lift to complete this effort, the articulating ridge lines of each half dome removed.

When complete, the full steel roof far overhead, we will greatly reduce the thermal load on the Mars yard terrain, offer shade for crew members in already difficult to cool pressure suits, and reduce the ambient lighting to something closer to Mars than the direct, Arizona sun.

It took six months of research and negotiation to find a local company willing to work with this unusual building and within our limited budget. We are pleased to have engaged Skyland Roofing of Tucson, Arizona. The crew worked through difficult conditions, from 104F+ degrees to wind and rain, on scissor lift and cherry picker 24-40 feet off the deck. Thank you Skyland, foreman Mario, and crew Louis #1, Louis #2, Kevin, Elia, and Adrian for your services. And thank you LP Steel of Laveen, Arizona for the custom-made roofing panels delivered on time and at a reasonable price.