Illustration of Ablative Arc Mining Process. Credits: Amelia Greig
A NASA NIAC Phase 1 grant has been awarded to Amelia Greig of the University of Texas, El Paso to study an innovative mining technique called ablative arc mining. The process works by using a pair of electrodes to zap surface regolith with an electrical arc thereby ionizing it into its component constituents. The ablated ions are then sorted and collected by subjecting them to an electromagnetic field which separates the material groups by their respective mass. Such a system, when mounted on a mobile rover, could extract both water and metal ions in the same system.
The goal of the this grant is to identify a feasible ablative arc mining scheme for ISRU on upcoming lunar exploration sorties. The study will define the design of an ablative arc and electromagnetic transport system for extraction and collection of water, silicon, and nickel. The architecture should have an output of 10,000 kg/yr of water for use by lunar outposts or other operations. Finally, a trade study will be performed comparing the efficiency of the proposed concept against other ISRU processes such as microwave or direct solar heating which are designed to only collect a single constituent.
We’ll need ISRU methodologies to enable long-term space settlement on the Moon, Mars, in the Asteroid Belt or to support free space habitats. The ablative arc mining architecture may be an efficient alternative for extraction and collection of multiple volatile constituents in a single system when compared to methods that collect only one material at a time.
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.
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.
a) Artistic rendering of a megasatellite constellation of habitats with inclined mirrors for collection of sunlight – detail of individual habitats shown in b). Credits: Pekka Janhunen
Pekka Janhunen of the Finnish Meteorological Institute, Helsinki, Finland has just posted a paper on the arXiv server describing his concept for a megasatellite space settlement in orbit around Ceres and constructed from materials from this dwarf planet in the asteroid belt. Ceres is chosen because of the availability of nitrogen and water needed for life support. A space elevator is proposed as an efficient means of lifting materials off the surface.
Janhunen works out the physics and mass budgets for a collection of settlements comprising the megasatellite, each providing 1g artificial gravity and a closed-loop life support system. The assemblage is made up of a collection of self contained rotating habitats which are interconnected and could potentially grow to house billions of people with 2000 square meters of living area per person. Each habitat would include soil thick enough to enable biomes with trees and ideal weather.
SSP covered another free space settlement concept by this author last April a bit closer to home at L5 in the Earth-Moon system. Janhunen discussed this duel-dumbbell design on The Space Show in May of last year.
Artist’s depiction of propulsion concept using Directed Energy. At left, Directed Energy Launch Technology Array (DELTA) beams power to laser powered electrical propulsion (LEP) spacecraft for rapid travel to the outer solar system or for laser sailing to the stars. At right, a sub-module from a close packed array of laser emitters within DELTA. Credits: Todd F. Sheerin / International Astronautical Federation
A concept for fast transit to the outer solar system and beyond has just been published by Todd F. Sheerin et al.* in Acta Astronautica. Since the article is behind a paywall, SSP has obtained permission by one of the coauthors, Professor Philip Lubin at the University of California, Santa Barbara to link to an earlier version of the paper presented at the 70th International Astronautical Congress held in Washington D.C. back in October 2019. Professor Lubin is Director of the Experimental Cosmology Laboratory at UCSB where he oversees research on several interesting directed energy projects.
The concept makes use of an Earth-based Directed Energy Launch Technology Array (DELTA) to beam laser energy to photovoltaic cells on an electric propulsion vehicle for travel within the solar system, or for photon reflection via a laser sail on gram-scale spacecraft accelerated to relativistic speeds for interstellar missions. In the former case, this method leverages existing solar electric propulsion technology which converts optical energy to propulsive jet power like what was used on NASA’s Dawn mission. An existing NASA Innovative Advanced Concepts (NIAC) program at UCSB has demonstrated proof of concept for elements of the array.
The DELTA architecture development can be terraced in progressive stages starting with small one meter arrays building up to large 10 km systems. The concept could support a range of missions, from swarms of gram-scale robots all the way up to human-rated spacecraft greater than 100 tons.
The authors believe this approach “… enables a scalable, cost effective roadmap to rapid solar system transportation for robotic and human missions alike, including robotic and human Mars-in-a-Month missions, with transit times of 30 days, as well as the first robotic relativistic interstellar flight within our lifetime.”
* Authors: Todd F. Sheerin, Elaine Petro, Kelley Winters, Paulo Lozano, Philip Lubin
Illustration of a nuclear thermal rocket in low earth orbit. Credits: NASA
Two U.S. companies are partnering with NASA to develop new fuel sources and reactor designs for future nuclear-fueled crewed space missions. Nuclear thermal and fusion powered rockets could significantly reduce the travel time to the Red Planet, lowering the risk of radiation exposure and the cost of life support consumables.
In an article in IEEE Spectrum, freelance journalist Prachi Patel describes the challenges of designing space nuclear reactors that are safe and lightweight, which will be needed to propel exploratory missions to Mars. These type of space reactors have the added benefit of being able to switch from propulsion to a power source at their destination.
Seattle based Ultra Safe Nuclear Corporation has a reactor design that uses a grade of nuclear fuel enriched to less then 20% uranium classifying it below the limit of highly enriched uranium, thus reducing proliferation risks by nefarious actors. The company coats its microscopic uranium fuel pellets with ceramics in a zirconium carbide matrix. This design approach ensures that the fuel can withstand the extremely high temperatures and volatile conditions inside a nuclear thermal reactor.
BWX Technologies Corporation located in Lynchburg, Virginia has extensive space nuclear reactor experience and has been working under contract to NASA since 2017 to explore designs also using a temperature resistant ceramic composite fuel with low enriched (< 20%) uranium.
Both companies may benefit from the recent Trump Administration Space Policy Directive-6 released December 16 which aims to limit the use of highly enriched uranium in space nuclear reactors unless absolutely necessary. The Memorandum on the National Strategy for Space Nuclear Power and Propulsion specifies that “The use of highly enriched uranium (HEU) in SNPP [space nuclear power and propulsion] systems should be limited to applications for which the mission would not be viable with other nuclear fuels or non‑nuclear power sources.” Although Space Policy Directives can be negated or modified by new administrations this particular directive should have bipartisan appeal.
The article also mentions the Princeton Plasma Physics Laboratory’s Direct Fusion Drive that SSP covered last year. Fusion rockets, although further behind in technology readiness levels, hold promise to outperform fission-based propulsion as fusion reactions release up to four times as much energy.
The Space Show – the nation’s first talk radio show focusing on increasing space commerce, advancing space science and economic development, facilitating our move to a space-faring economy which will benefit everyone on Earth – needs your help. The Space Show is hosted by Dr. David Livingston, who completed his doctoral dissertation in 2001 on the commercialization and expansion of space development. Take a moment to visit The Space Show website and read Dr. Livingston’s end of year message. Please give generously to ensure this valuable resource continues to promote, encourage, and support future global economic opportunities, scientific discoveries, and medical advances for all humankind through peaceful and cooperative ventures in outer space.
Space is Open for Business by Robert Jacobson is a must-read for all potential “astropreneurs” (entrepreneurs involved the NewSpace economy), space advocates, investors or anyone who wants to keep current on space commerce and its impact on the future of humanity. This book is a refreshingly positive view of our future in space, a welcome alternative outlook in stark contrast to many dystopian and negative predictions of where we’re headed in today’s media.
Jacobson covers all aspects of the nascent space economy which has already begun to grow in leaps and bounds, and is headed for explosive growth in the near future. No stone is left unturned by his deep research of all aspects of space commerce, with scores of interviews of executives from both established and small startup space companies.
I especially liked the Sci-Fi and Society chapter in which Jacobson talks about science fiction “illuminating the possibility of the space frontier”. Much of what is now happening in space was predicted in science fiction in the last century. Many CEOs and executives of NewSpace companies were inspired to pursue careers in science or engineering through science fiction books, televisions shows and movies.
Eventually, humanity will evolve to migrate off Earth and establish space settlements throughout the solar system and eventually among the stars. Development of the technologies and commercial activities for space settlement have the potential to create vast wealth, bring billions of people out of poverty and preserve Earth’s natural environment. Jacobson has provided a hopeful glimpse of how the space businesses supporting this effort will manifest this destiny.
ESA astronaut Luca Parmitano loads microbes into the Kubik centrifuge facility on the International Space Station. Credits: ESA
A research team at the University of Edinburgh in the UK has just published an analysis of data from an experiment on the International Space Station that could lead to “biomining” on Mars or an asteroid. Published in Nature Communications on November 10, Cockell, C.S., Santomartino, R., Finster, K. et al.* present experimental results demonstrating microbiological leaching of rare Earth elements from basalt rock, an analogue for much of the regolith material on the Moon and Mars. Called BioRock, the ESA sponsored experiment examined three species of microorganisms under variable gravity conditions in the Kubik centrifuge facility located in Europe’s Columbus module on the ISS.
This technology is a significant breakthrough for in situ resource utilization. By “living off the land” on the Moon, Mars or an asteroid, space settlers could have an available source of valuable materials used in electronic devices and many other high-technology applications. These rare Earth elements and the traditional heavy mining equipment needed to extract them would not have to be launched from Earth, significantly reducing transportation and processing costs. Positive results were found under Earth gravity, Mars gravity and microgravity conditions. The authors conclude that the experiment “…shows the efficacy of microbe–mineral interactions for advancing the establishment of a self-sustaining permanent human presence beyond the Earth and the technical means to do that.”
Artist’s rendering of settlements on the Moon. Credits: Taylor Herring/Samsung via Futurism.com
A melding of multiple disciplines is required for creating a positive human space future that will enable space settlement. In addition to aerospace engineering, architecture and the traditional physical sciences we associate with space exploration, the fields of sociology, philosophy, art, space law and may others will be needed. A method for integrating these fields and coordinating them across the private sector, universities and government has been developed in The Interplanetary Initiative, a pan-university venture created at Arizona State University. The innovative research model is described in a paper in the September 2020 issue of New Space. The program turns students into team leaders and collaborators, equipping them with the skills and knowledge to solve problems anticipated to be encountered as humans expand out into the solar system.
