Artist’s illustration of a self replicating factory near an asteroid and serviced by a SpaceX Starship. Credits: Michel Lamontagne / Principium
The technology of self replicating machines has been gradually progressing toward maturity over the last few decades. The Space Studies Institute recognized this key enabler of space settlement as far back as the 1980s and covered the topic frequently in its newsletter updates. Now Michel Lamontagne has provided a status update in the latest issue of Principium. On page 50, he highlights the history of self replicating factories, provides a vision for the evolution of the concept for production of space settlement infrastructure and gives a summary of recent developments in key areas of research such as additive manufacturing, machine learning and cheap access to space that will be enablers of this space based industry.
The first factory will be built on the Moon after deep learning simulations prove the concept on Earth. Eventually the more autonomous versions would migrate to Mars and then to what may be the best suited location, the asteroid belt which “…may be the ultimate resource for space settlement construction.” Lamontagne believes “These factories would then follow humanity to the Stars, after having helped to build the infrastructure required for the occupation of the solar system and for Interstellar travel.”
Artist’s rendering of an early self replicating factory on the Moon with SpaceX Starships serving as basic construction elements. Credits: Michel Lamontagne / Principium
Orbiting Modular Artificial-Gravity Spacecraft (OMAGS) concept for testing ecosystems in space – Exterior and cutaway views. Credits: Gregory Dorais / NASA
One of the most important technologies to realize permanent space settlements is the development of self-sustaining controlled ecological life support systems (CELSS). This will require replication of independent self-contained subsets of Earth’s biosphere containing select flora and fauna under controlled conditions for eventual human life support. But are 100% closed ecosystems (with the exception of the exchange of radiation and information) beyond Earth possible? Could a series of controlled evolutionary experiments using machine learning be carried out on controlled ecosystems in space under variable gravity conditions to rapidly optimize the key variables needed to identify the smallest possible CELSS for long term human survival? Gregory Dorais, a research scientist at NASA Ames Research Center, thinks so and describes the strategy in a paper called An Evolutionary Computation System Design Concept for Developing Controlled Closed Ecosystems.
Dorais introduces his concept with a brief description of Closed EcoSystems (CESs) and early efforts by NASA to develop a CELSS for space settlement. Of particular concern are the challenges of putting humans in the equation. There are consequences related to the ratio between human biomass and non-human biomass in ecosystems. On Earth this ratio is low so the ecosystem can self-regulate compensating for imbalances. But in a space biosphere, this ratio in the life support system is comparatively huge leading to significant challenges in maintaining equilibrium. For example, the ISS needs frequent resupply of consumables by spacecraft to replenish losses in the life support system. Wastes that cannot be recycled are either incinerated in the Earth’s atmosphere or exhausted into space. A completely closed system that is self-sustaining has not yet been developed.
Dorais’ design concept for an experimental testbed can be used to explore the viability of different biomass ratios of various combinations of larger animal species and eventually humans. The system consists of a collection of independent CESs controlled and interconnected to generate data for machine learning toward optimizing long term viability. Gradually, the size of the animals in the CES can be increased evolving over time with the ultimate goal of human life support. To kick things off, an Orbiting Modular Artificial-Gravity Spacecraft (OMAGS) is proposed, with room for 24 CESs housed in a 150cm radius centrifuge with appropriate radiation shielding capable of testing the ecosystems under different fractional gravity conditions. The spacecraft is envisioned to be placed in an elliptical orbit in cis-lunar space.
To scale illustration of the OMAGS proposed mission orbit in cislunar space. Credits: Gregory Dorais / NASA
The OMAGS spacecraft has been sized to fit in a SpaceX Falcon Heavy payload fairing.
Illustration of a OMAGS payload sized for a SpaceX Falcon Heavy launch vehicle. Credits: Gregory Dorais / NASA
A NASA patent and tech transfer fact sheet entitled Closed Ecological System Network Data Collection, Analysis, Control, and Optimization System has been issued for this innovation under the NASA Technology Transfer Program.
In a related presentation delivered in November 2018, Dorais says “Once CESs are demonstrated to reliably persist in space, within specified gravity and radiation limits, it is a small step for similar CESs to persist just about anywhere in space (Earth orbit, Moon, Mars, Earth-Mars cycler orbit, asteroids, …) enabling life to permanently extend beyond Earth and grow exponentially.”
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.
Schematic of a Mars settlement methane production system for a single SpaceX Starship over a period of two years. Electrolysis and hydrogen storage are off the shelf. Sabatier reactor needs to be developed. Credits: Michel Lamontagne / marspedia.org
Early missions to Mars such as Robert Zubrin’s Mars Direct architecture will require propellant production for the trip home. Methane can be produced in situ on the red planet’s surface through the basic chemical reaction CO2 + 4H2 → CH4 + 2H2O. A French chemist named Paul Sabatier discovered back in 1897 that this reaction could be facilitated by a nickel catalyst in the presence of hydrogen and carbon dioxide at elevated temperatures. Since water ice is present on Mars, hydrogen could be produced though electrolysis of water. Combining these two reactions into a methane production system, Michel Lamontagne has provided a schematic of the whole process on marspedia.org. By design, the SpaceX Starship uses methane for fuel. The company may want to prioritize development of a flight-ready Sabatier reactor for this system to enable the transportation infrastructure needed for supplying a settlement until it can become self sufficient.
Artist rendering of a SpaceX Starship lifting off near a Mars settlement. Credits: SpaceX / Flickr
Artist depiction of SpaceX Crew Dragon in Lunar Orbit. Credits: Bruce Irving/Flickr
Robert Zubrin advocates for a quick decision by NASA and the National Space Council on a mission using SpaceX hardware to put a Dragon capsule in orbit around the Moon before the end of the year. In a letter to Jim Bridenstine and Scott Pace, he suggests lofting a crew to low Earth orbit in a Crew Dragon using a Falcon 9 launch vehicle. This would be followed up by launching a Falcon Heavy for rendezvous in LEO with its upper stage containing surplus propellant. The Falcon Heavy upper stage could then propel the Dragon to the Moon in an “Apollo 8” type mission ending with a splashdown of Dragon in the ocean.
Only slight modifications would need to be made to the Dragon to carry enough oxygen for a 6 day journey. The capsule is already designed for Earth capture from a Mars trajectory so return from the Moon should not be a problem. Zubrin’s proposal was sent in a memo to the NASA Administrator and the Executive Secretary of the National Space council on June 30, and reprinted in the Space Review July 6. Such a demonstration could inspire the nation and initiate validation of essential cislunar infrastructure toward settlement of the Moon.
Artist rendition of Starship exploring Saturn. Image credit SpaceX/Flickr
In an interview by Stuart Clark in BBC Science Focus Magazine, Vice President for North American operations for the International Space University Gary Martin answers questions on how private enterprise is changing space exploration. Companies like SpaceX and Blue Origin, through their own initiatives and public/private partnerships are opening up the final frontier, paving the way for space settlement.
In a thread on Twitter, Kevin Cannon suggests that suppliers for services that SpaceX will need to settle Mars such as sanitation, medical supplies, entertainment, finance and others, get started sooner rather then later laying out their plans if they want to be selected to help settle a new world.
Eric Berger chronicles the ten year history of SpaceX’s flagship launch vehicle. The versatile, reusable workhorse has been the proving ground for the technology that will make Elon Musk’s vision of low cost interplanetary space travel a reality in the near future.
Falcon 9 historic launch of NASA astronauts Doug Hurley and Bob Behnken aboard Crew Dragon. Image courtesy of SpaceX
In what is sure to be a historic flight next year, Axiom has inked a deal with SpaceX to be the first space tourism company to arrange for three private astronauts to be ferried to the ISS on a Crew Dragon. A fourth space flight participant will be a SpaceX trained astronaut. Axiom has plans for a permanent replacement of the ISS to provide a permanent habitat, scientific and industrial facility in LEO
