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Curriculum for Astrochemical Engineering

An engineer pondering chemical processes for use in space learned in an advanced postgraduate course in Astrochemical Engineering. Credits: DALL∙E 3

In a paper in the journal Sustainability a global team of researchers has created a two year curriculum to train the next generation of engineers who will design the chemical processes for the new industrial revolution expected to unfold on the high frontier in the next few decades.

Current chemical engineering (ChE) training is not adequate to prepare the next generation of leaders who will guide humanity through the utilization of material resources in space as we expand out into the solar system.

Astrochemical Engineering is a potential new field of study that will adapt ChE to extraterrestrial environments for in situ resource utilization (ISRU) on the Moon, Mars and in the Asteroid Belt, as well as for in-space operations. The body of knowledge suggested in this paper, culminating in Master of Science degree, will provide training to inform the design ISRU equipment, life support systems, the recycling of wastes, and chemical processes adapted for the unique environments of microgravity and space radiation, all under extreme mass and power constraints.

The first year of the program focuses on theory and fundamentals with a core module teaching the physical science of celestial bodies of the solar system, low gravity processes, cryochemistry (extremely low temperature chemistry), and of particular interest, circular systems as applied to environmental control and life support systems (ECLSS) to recycle materials as much as possible. Students have the option to specialize in either process engineering or a more general concentration in space science.

For the process engineering option in year one, students will learn how materials and fluids behave in the extreme cold of space. This will include the types of equipment needed for processes in a vacuum environment including microreactors and heat exchangers, as well as methods for separation and mixing of raw materials.

In the space science specialization, year one will include production of energy and its utilization in space. Applications include solar energy capture and conversion to electricity, nuclear fission/fusion energy, artificial photosynthesis, and the role of energy in life support systems.

In the second year, students learn basic chemical processes for ISRU on other worlds. Processes such as electrolysis for cracking hydrogen and oxygen from water; and the reactions Sabatier, Fischer-Tropsch and Haber-Bosche for production of useful materials.

The second year process engineering specialization focuses on ISRU on the Moon with ice mining, processing regolith and fluid transport under vacuum conditions. Propulsion systems are also covered including methane/oxygen engines, hydrogen logistics, cryogenic propellent handling in space and both nuclear thermal and electric propulsion. Space science specialization in year two covers life support systems and space agriculture.

A design project is required at the end of each year to demonstrate comprehension of the concepts learned in the curriculum, and is split between an individual report and a group project.

Coupled with synthetic geology for unlocking a treasure trove of space materials in the Periodic Table, innovative equipment for ISRU on the drawing board and research on ECLSS, Astrochemical Engineering will be a valuable skill set for the next generation of pioneers at the dawn of the age of space resource utilization.

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Mars as breadbasket for the outer solar system

Artist’s rendering of a farming settlement on Mars. Credits: HP Mars Home Planet Rendering Challenge via International Business Times.

Space settlement will eventually require space farming to feed colonists and to provide life support. It’s clear that we will replicate our biosphere wherever we go. In that spirit, Bryce L. Meyer envisions Mars as the breadbasket of the outer solar system. In a presentation at Archon 45, a science fiction and fantasy convention held annually by St. Louis area fans, he makes the case for why the fourth planet would be the ideal spot to grow crops and feed an expanding population as part of the roadmap to agriculture in space.

Carbon dioxide and subsurface water ice are plentiful on Mars, critical inputs for crop photosynthesis. There is also evidence of lava tubes there which could provide an ideal growing environment protected from radiation, micrometeorite bombardment and temperature extremes. The regolith should provide good nutrients and there is already research on methods to filter out perchlorates, a toxic chemical compound in the Martian soil.

Image of Lava tubes on the surface of Mars as photographed by ESA’s Mars Express spacecraft. Credits: ESA/DLR/FU Berlin/G Neukum / NewScientist

Another advantage that Mars holds as a food production hub for the asteroids and beyond is its placement further out in the solar system. Since it is higher up in the sun’s gravity well, Meyer calculates that it would take less than 43% of the fuel needed to transport goods from Mars outward than from Earth. He even suggests that with its lower gravity and recent advancements in materials research, a space elevator at Mars could be economically feasible to cheaply and reliably transport foodstuff off the planet.

Meyer keeps a webpage featuring space agriculture, terraforming, and closed cycle microgravity farming where he poses the question “Why settle space?” I like his answer: “Trillions of Happy Smiling Babies!!!”

Basic input/output diagram of an environmental control and life support system like what would be expected in a space farm. Credits: Bryce L. Meyer

Meyer is the founder and CEO of Cyan React, LLC, a startup that designs compact photobioreactors and provides expertise in closed-cycle farming and life support especially for space settlement and space habitats. He is also a National Space Society Space Ambassador doing his part to educate the public about the potential benefits to humanity through the use of the bountiful resources in space. In a presentation at this year’s International Space Development Conference, he describes his research on bioreactors explaining how settlers will grow food and recycle waste sustainably on the high frontier.

Diagram depicting the flow of materials in a closed space farm habitat utilizing bioreactors. Credits: Bryce L. Meyer

Complete closure and stability of an environmental control and life support system (ECLSS) is challenging and not without limitations. As launch and space transportation costs come down in the near future and off-Earth supply chains become more reliable, complete closure will not be required at least initially. In situ resource utilization will provide replacement of some ECLSS consumables where available for colonists to live off the land. As missions go deeper into space reaching the limits of supply chain infrastructure and even out to the stars, closure of habitat ECLSS and resource planning will become more important. Meyer has done the math for farms in space to provide food and air for trillions of smiling babies…and their families as they move out into the solar system.

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Stability and limitations of environmental control and life support systems for space habitats

Image of Biosphere 2, a research facility to support the development of computer models that simulate the biological, physical and chemical processes to predict ecosystem response to environmental change. Credits: Biosphere 2 / University of Arizona

Once cheap access to space is realized, probably the most important technological challenge for permanent space settlements behind radiation protection and artificial gravity is a robust environmental control and life support system (ECLSS). Such a system needs to be reliably stable over long duration space missions, and eventually will need to demonstrate closure for permanent outposts on the Moon, Mars or in free space. In his thesis for a Master of Science Degree in Space Studies, Curt Holmer defines the stability of the complex web of interactions between biological, physical and chemical processes in an ECLSS and examines the early warning signs of critical transitions between systems so that appropriate mitigations can be taken before catastrophic failure occurs.

Holmer mathematically modeled the stability of an ECLSS as it is linked to the degree of closure and the complexity of the ecosystem and then validated it against actual results as demonstrated by NASA’s Lunar-Mars Life Support Test Project (LMLSTP), the first autonomous ECLSS chamber study designed by NASA to evaluate regenerative life support systems with human crews. The research concluded that current computer simulations are now capable of modeling real world experiments while duplicating actual results, but refinement of the models is key for continuous iteration and innovation of designs of ECLSS toward safe and permanent space habitats.

This research will be critical for establishing space settlements especially with respect to how much consumables are needed as “buffers” in a closed, or semi-closed life support system, when the model’s metrics indicate they are needed to mitigate instabilities. Such instabilities were encountered during the first test runs of Biosphere 2 in the early 1990s.

As SpaceX races to build a colony on Mars, they will need this type of tool to help plan the life support system. Holmer believes that completely closed life support systems for relatively large long term settlements are at least 15 to 20 years away. That means that SpaceX will need to resupply materials and consumables due to losses in their initial outpost who’s life support system in all probability will not be completely closed during the early phases of the project over the next decade. Even SpaceX cannot reduce launch costs low enough to make long term resupply economically viable. They will eventually want to drive toward a fully self sustaining ECLSS. That said, depending on how the company funds its initiatives and sets up it’s supply chains, they may not need a completely closed system for quite some time.

Of course there are sources of many of the consumables on Mars that could support a colony but not all the elements critical for ecosystems, such as nitrogen, are abundant there. There are sources of some consumables outside the Earth’s gravity well which could lower transportation costs and extend the timeline needed for complete closure. SSP covered the SHEPHERD asteroid retrieval concept in which icy planetesimals, some containing nitrogen and other volatiles needed for life support, could be harvested from the asteroid belt and transported to Mars as a supply of consumables for surface operations. TransAstra Corporation is already working on their Asteroid Provided In-situ Supplies family of flight systems that could help build the infrastructure needed for this element of the ecosystem. It may be a race between development of the competing technologies of a self-sustaining ECLSS vs. practical asteroid mining. The bigger question is if humans can thrive long term on the surface of Mars under .38G gravity. In the next century, O’Neill type colonies, perhaps near a rich source of nitrogen such as Ceres, may be the answer to where safe, long term space settlements with robust ECLSS habitats under 1G will be located.

Curt Holmer appeared recently on the The Space Show discussing his research. I called the show and asked if he had used his modeling to analyze the stability of ecosystems sized for an O’Neill-type colony. He said he had only studied habitats up to the size of the International Space Station, but that it was theoretically possible to analyze this larger ecosystem. He said he would like to pursue further studies of this nature in the future.

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SAM: Space Analog for the Moon and Mars

Exterior view of SAM. Credits: samb2.space
Interior view of greenhouse controlled environment with depiction of SIMOC temperature, humidity, and carbon dioxide level control panel. Credits: samb2.space

Located at the iconic Biosphere 2 facility in Arizona, SAM is a hi-fidelity, hermetically sealed science center about to begin cutting edge research into environmental control and life support systems (ECLSS). The facility will host researchers to perform experiments on plant physiology, regolith chemistry, food cultivation and a host of other studies in the context of a space habitat analog.

Utilizing the original Test Module which completed three closed cycles to test water and human waste recycling prior to the main Biosphere 2 facility construction, SAM will be fitted with an airlock and pressurized enclosure including quarters for research crews to stay up to two weeks at a time.

Of particular interest, SAM in partnership with National Geographic, will help validate SIMOC, an interactive closed-loop life support system simulator based on authentic NASA data. Feedback from SAM will refine the SIMOC mathematical model that balances food, air, water, agriculture and solar energy to support humans in a closed ECLSS.

SIMOC was developed though a grant by Arizona State University’s Interplanetary Initiative. Unveiled at the Mars Society 23 Annual International Convention last October (see page 87 of the Conference Abstract) the software is licensed and hosted by the National Geographic Society for integration into classrooms globally where curricula is provided for teachers to get students involved as citizen scientists to design habitats to sustain human life on the Moon and Mars.

Screen shot of SIMOC habitat interactive simulation software. Credits: Kai Staats / National Geographic Society

As stated on the SAM at B2 website:

“There is no single-run experiment that results in the ideal solution for providing breathable air, recycled water, food and waste reprocessing. Rather, we will see an unfolding of experiments, findings, and prototypes for decades to come. Much as farming evolved from the art of crop rotation to the science of genetically modified organisms, living on the Moon, Mars, and in free space will demand constant improvements in our systems as more humans move to off-world homes.”

Kai Staats, Director at SAM, was a recent guest on The Space Show where he provided a history of the creation of the facility and his role in developing SIMOC.

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The feasability of interstellar worldships

Artist’s impression of a fleet of worldships on an interstellar voyage. Credits: Michel LaMontage / Initiative for Interstellar Studies

In the August 2020 Issue of Principium, Richard Soilleux summarizes current research on the feasibility of interstellar voyages via multi-generation worldships. The starting point is assumed to be free flying orbital settlements as envisioned by Gerard K. O’Neill that will eventually be tooling around the solar system way before a trip to the stars would be possible. The baseline for the analysis was an orbital space settlement called Avalon, the result of a complex study by the British Interplanetary Society called the BIS Space Project which took a fresh look at O’Neill’s smallest habitat Island 1, a settlement that would house 10,000 inhabitants.

Artist’s impression of the Avalon orbital settlement. Credits: Mark Hempsell / Initiative for Interstellar Studies

Much of the technology needed for an interplanetary ship like Avalon could be leveraged for an interstellar craft, but there are several challenges for permanent occupation over many generations as would be needed for a trip to the stars. For example, the ships would obviously have to be much more robust and reliable. Design lifetimes of 1000 years, as what is estimated to be needed, would require rigorous maintenance and repair schedules. Major periodic replacement of damaged or worn components and obsolete parts would also be required.

Soilleux’s analysis breaks down the key features of the settlement in terms of technology readiness and extrapolates to the interstellar case. One key element of the design is the environmental control and life support system (ECLSS). Avalon’s ECLSS does not need to be fully closed when voyages are limited to within the solar system as there are plenty of resources to replace nutrients and materials that cannot be recycled. Interstellar voyages are another matter all together and the study found that the recycling rate needs to be better than 90% for at least 36% of a material to remain useable after 100 years. This ratio would have to be significantly higher for an interstellar journey, the duration of which could be an order of magnitude longer. Soilleux concludes that “Recycling must therefore be managed carefully, and a detailed inventory maintained of all materials and nutrients wherever they are in the system.”

ECLSS technology is clearly one of the gating items for space settlement in the solar system and for journeys beyond. More information and research can be found in the Life Support Section.