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Seeding asteroids with fungi for space habitat soil

Illustration of a process for making soil for space habitats by seeding asteroids with fungi. Credits: Jane Shevtsov

The asteroid belt will be a treasure trove of raw material for space settlers to use to build their habitats, especially the O’Neill-type rotating cylinder variety. To support plentiful green spaces and robust agricultural systems envisioned for these large scale settlements, an abundant source of fertile soil will be needed. But how could the enormous cost of bringing soil from Earth be avoided? An innovative in situ method under development by Jane Shevtsov of Trans Astronautica Corporation may provide the answer. In a just awarded NASA NIAC Phase 1 grant proposal, she explains that the envisaged soil-making process would be a “…natural fit for asteroid mining operations targeting volatiles, as they use carbonaceous asteroids and leave behind leftover regolith that should make a suitable parent material for soil production.”

The Phase 1 research will be broken down into two tasks. In Task 1 the leading fungal species will be identified for experimentation on asteroid material simulant followed by determination of soil production rates of the fungi along with the effects of environmental factors such as temperature, humidity and oxygen concentration. Task 2 will explore various methods of breaking down asteroid regolith by the chosen fungi in the space environment optimizing for productivity and costs, with the ultimate goal of determining the size of a payload to support a reference mission habitat within a feasible timeframe.

In the above diagram, there are hints that the concept may use an inflatable enclosure around the asteroid to retain volatiles, reminiscent of some of the applications of the SHEPHERD asteroid capture architecture previously covered by SSP, in which a gas atmosphere within the enclosure can keep water in a liquid phase so that the asteroid provides a substrate for introduced biological agents for the generation of foodstuffs and other consumables.

Trans Astronautica has been working on their own asteroid capture method which may come in handy when used in combination with the output of Ms. Shevtsov’s project.

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Cyanobacterium-Based Life-Support Systems on Mars

Diagram of a Mars based life-support system using cyanobacteria fed from in situ resources to decrease dependence on Earth-imported materials. Credits: Cyprien Verseux et al.* via Frontiers in Microbiology

A Team* of researchers at the University of Bremen, Germany has just published results of an experiment to grow cyanobacteria fed from regolith and atmospheric gases available on Mars. The study, published in the February 16 2021 issue of Frontiers in Microbiology, showed that an analog of Martian regolith consumed as a nutrient source by cyanobacteria which could then potentially be used to feed secondary heterotopic consumers downstream in a life support system producing food, oxygen, energy and recycling functions.

The results of the study indicate that a low pressure mixture of gases extracted from the Martian atmosphere would be suitable for a photobioreactor of cyanobacterium-based life-support system. More work is needed to optimize the design of such systems on Mars, such as investigating the effects of different concentrations of N2 on cyanobacteria, variation in the composition of regolith mixtures, and the transfer of nutrients from cyanobacteria to organisms downstream in the life support system.

In an email to Dr. Cyprien Verseux, the lead author on the paper, I asked about using E. Coli as a secondary consumer in the study. He responded: “We used E. coli as a model here, but it does not mean that we suggest using this bacterium specifically. The point was to show that heterotrophic organisms could be fed using cyanobacteria, which themselves could be fed using resources available on Mars. It is on purpose that we remained vague on the downstream processes: what we’re trying to develop is not a BLSS [bioregenerative life-support systems] per se, but rather a way of connecting [a] BLSS, some of which are being developed by others (see, e.g., the MELiSSA project), to resources available on Mars.”

When asked about planetary protection concerns about introducing cyanobacteria into the Martian environment even though appropriate precautions would likely be taken to completely contain the organisms within the BLSS, Dr. Verseux, said “Certainly, we need to bring the risk of outward contamination as close to zero as reasonably possible. A low pressure inner pressure is a first step: it reduces the risks related to leakage. Other potential measures include the use of several levels of confinement, and the installation of the setup far from areas of astrobiological interest.”

Dr. Verseux has more information about using green bacteria on the Red Planet on is blog Walking on Red Dust.

Artist’s rendering of a cyanobacterium-based life-support system on Mars (CyBLiSS). Credits: Sean McMahon (artistic work) and Cyprien Verseux (source)

* Authors: Cyprien Verseux, Christiane Heinicke, Tiago P. Ramalho, Jonathan Determann, Malte Duckhorn, Michael Smagin and Marc Avila – Center of Applied Space Technology and Microgravity (ZARM), University of Bremen, Bremen, Germany

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Worldships for interstellar space settlement

Image of an interstellar Worldship. Credits: Michel Lamontagne / Principium, Issue 32, February 2021

The feasibility of Worldships has been covered previously on SSP by The Initiative and Institute for Interstellar Studies via Principium. A new article by Michel Lamontagne on page 29 of the most recent issue examines the concept from a perspective of an interplanetary society which has harnessed fusion energy and life support systems for space settlements, while reducing costs through self replicating factories.

Such a starship is envisioned to use a deutrium/He3 fusion drive to accelerate to 1% of the speed of light completing a journey to Alpha Centauri in about 430 years. The author envisions a fleet of 3 or 4 (or more) Worldships housing about 1000 passengers each in rotating torus habitats 1,200m in diameter with artificial gravity.

Image of the interior of a worldship habitat. Credits: Michel Lamontagne / Principium, Issue 32, February 2021

Self replication is the key to this architecture. Lamontage explains: “If fully self replicating systems exist at the departure of the mission, Sprinter starships carrying self replicating machines can be sent at the same time as the Worldship flotilla departs. The Sprinters will arrive centuries before the Worldships, and the self replicating machines will have ample time to create multiple habitats, and perhaps begin to seed them with simple life forms.”

Lamontage cautions that the needed AI technology and practical self replicating machines may be more difficult to develop than predicted. The Worldship habitat ecosystems may encounter instabilities over centuries-long journeys leading to eventual breakdown of life support systems. Finally, rapid technological advances may lead to advanced propulsion schemes or other opportunities that would make a Worldship obsolete before getting started.

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Power towers at the Peaks of Eternal Light

Peaks of Eternal Light at the lunar south pole annotated with crater labels. Mosaic of 40 images taken by the ESA SMART-1 spacecraft 2005/2006. Area covers 500 x 150 km. Credits: ESA/SMART-1/AMIE camera team; M. Ellouzi/B. Foing, CC BY-SA 3.0 IGO

As most space settlement enthusiasts know, the Peaks of Eternal Light on the rims of craters in the lunar polar regions hold much promise as the ideal location to place collectors for solar energy to power ice mining operations. At the south pole in particular, these peaks lie within just a few kilometers of large frozen water deposits in the permanently dark shallows. But how much solar power is available? Companies such as Trans Astronautica Corporation will want to know so they can inform plans for their Sun Flower™ collector invention as part of a Lunar Polar Mining Outpost.

In a paper posted this month on the pre-print server arXiv.org, a team of researchers at Harvard University and Technische Universität Berlin present the results of a study to answer this question. Using data from high resolution maps of solar illumination on the ridges of Shackleton crater and others, they determined the total available power from collector towers of various heights if they were placed at these locations.

The study found that the power available depends heavily on the height of the panels above the local surface but could be substantial, from a few megawatts for towers of heights less than 100m up to the gigawatt range for towers of 500m or more. This is sufficient power for mining several thousand tons of water per year from Shackleton crater.

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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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DARPA announces Novel Orbital and Moon Manufacturing, Materials and Mass-efficient Design (NOM4D) program

Artist’s concept of projects which could benefit from DARPA’s (NOM4D) plan for robust manufacturing in space. Credits: DARPA

Pronounced “NOMAD” the Defense Advanced Research Projects Agency plan aims to develop technologies for adaptive, off-earth manufacturing to fabricate large structures in space and on the Moon.

Bill Carter, program manager in DARPA’s Defense Sciences Office explains in an announcement of the program, “We will explore the unique advantages afforded by on-orbit manufacturing using advanced materials ferried from Earth. As an example, once we eliminate the need to survive launch, large structures such as antennas and solar panels can be substantially more weight efficient, and potentially much more precise. We will also explore the unique features of in-situ resources obtained from the moon’s surface as they apply to future defense missions. Manufacturing off-earth maximizes mass efficiency and at the same time could serve to enhance stability, agility, and adaptability for a variety of space systems.”

The program will be split into three 18 month phases driven by metrics associated with progressively challenging exemplars such as respectively, a 1-megawatt solar array, a 100m diameter RF reflector, and finally IR reflective structures suitable for use in a segmented long-wave infrared telescope.

Lessons learned from the program could be applied to on-orbit manufacturing operations by commercial space companies as launch costs come down and access to cislunar space becomes more routine for both government and commercial entities.

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Are we on the right track for space settlement?

Artist depiction of an O’Neill cylinder from the novel K3+. Credits: Katie Lane (Full distribution rights reserved by Erasmo Acosta)

Erasmo Acosta thinks we might be headed in the wrong direction, that we may be suffering from planetary chauvinism and the better way may be to colonize space with O’Neill cylinders. He makes his case in a post on the Predict section of Medium. SSP has long been a strong proponent of free space O’Neill-type settlements, the advantages of which are numerous, not the least of which is 1G artificial gravity to prevent detrimental human health issues that may arise for occupants of colonies with lower gravity on the Moon or Mars. Such space settlements would house millions of people in perfect 70 degree controlled weather without the threat of natural disasters.

Jeff Bezos has advocated for this philosophy with the aim of moving heavy industry off world and preserving Earth’s environment for “residential zoning”. Recent developments seem to indicate he may be spending more of his time focusing on the realization of that vision.

Acosta, a retired software engineer, feels so strongly that O’Neill cylinders will be the preferred mode of space settlement he wrote a novel called K3+ which depicts a future in the next century where humans will be living in thousands of O’Neill cylinders in a “post-scarcity” civilization of virtually unlimited resources. Acosta envisions Mercury as a source of raw materials:

“The planet’s proximity to the sun, its low gravity, and metal-rich concentration make it the ideal source of raw materials for constructing thousands of O’Neill cylinders.”

In a previous post on Predict, he explains how to kickstart a program for harnessing space resources to fabricate these colonies.

After many years of construction, multiple rings of rotating habitats would eventually encircle the sun harnessing a vast amount of the energy output of our star approaching the configuration of a Dyson sphere.

Artist depiction of multiple rings of rotating habitats around the sun. Credits: Katie Lane (Full distribution rights reserved by Erasmo Acosta)

Finally, as a tribute to the father of free space colonies and an inspiration for a generation of space settlement advocates, I’d like to close out this post with a link to the just released trailer for the much anticipated documentary: The High Frontier, The Untold Story of Gerard K. O’Neill.

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Simpler methane production on Mars

Artist’s depiction of activities at an early Mars base which could include methane production. Credits: NASA

A team of physicists at the University of California, Irvine has found a short cut for efficient propellant production on Mars. The UCI researchers have discovered a way to streamline the conventional two step Sabatier process which first electrolyzes water into hydrogen before reacting with carbon dioxide in the Martian atmosphere to create methane. Both SpaceX and Blue Origin use methane in their rocket engine designs. The novel approach simplifies fuel production by leveraging zinc as a “synthetic enzyme,” which catalyzes carbon dioxide to synthesize methane directly. The improved process will reduce the amount of ISRU equipment (and therefore weight and launch costs) needed for transport to the surface of Mars to facilitate propellent production required for the trip home. The research has only demonstrated proof of concept so follow-on studies are required to improve the TRL for flight-ready hardware.

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Project MOONRISE demonstrates 3D printed regolith structures under lunar gravity conditions

Artist impression of the MOONRISE laser mounted on a lunar rover for fabrication of structures on the Moon. Credits: Laser Zentrum Hannover / 3D Printing Industry

A German company called Laser Zentrum Hannover .eV in partnership with the Technical University of Braunschweig has been working on a project called MOONRISE which aims to use laser technology to build a village on the Moon out of lunar regolith. Toward that end, the team for the first time has demonstrated the ability to 3D print structures out of simulated lunar regolith under lunar gravity conditions. The results of their experiments are described in an article in 3D Printing Industry.

The research was carried out in the Leibniz University Hannover’s Einstein-Elevator, a large-scale drop tower device in which experiments can be run under variable gravity conditions at a high repetition rate.

Initiated in 2019, Project MOONRISE is funded by the Volkswagen Foundation and is focused on improving the technology readiness level of additive manufacturing using lunar regolith as building material.

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Survey of industry experts on challenges of lunar ISRU by 2040

Artist impression of ISRU activities on the Moon. Credits: NASA

What do space experts in industry and academia think will be the technical and policy challenges to overcome for a sustainable lunar outpost leveraging ISRU by 2040 to be realized? A survey using the Delphi method has just been completed to answer this question. The results were just released as a pre-proof in Acta Astronautica. Significant contributors in the fields of ISRU technologies, space architecture, power systems, and space exploration participated in the survey.

There was a group consensus that NASA’s Artemis mission returning humans to the Moon would be delayed by at least 2 years from the previous administration’s target of 2024 due to uncertainty in U.S. policy over the next few years. No surprise here. There was also agreement that ISRU processes could add significant power requirements on the order of 1 MW to a lunar base, and that photovoltaic systems were preferred over nuclear power sources because of a “…political distaste for space nuclear power systems”. Of particular note, the survey participants could not reach agreement on the impact that Covid-19 would have on space exploration.