Posted on

Highlights from the International Space Development Conference

Conceptual illustration of Mag Mell, a rotating space settlement in the asteroid belt in orbit around Ceres – grand prize winner of the NSS Student Space Settlement Design Contest. Credits: St. Flannan’s College Space Settlement design team*

In this post I summarize a few selected presentations that stood out for me at the National Space Society’s International Space Development Conference 2022 held in Arlington, Virginia May 27-29.

First up is Mag Mel, the grand prize winner of the NSS Student Space Settlement design contest, awarded to a team* of students from St. Flannan’s College in Ireland. This concept caught my eye because it was in part inspired by Pekka Janhunen’s Ceres Megasatellite Space Settlement and leverages Bruce Damer’s SHEPHERD asteroid capture and retrieval system for harvesting building materials.

The title Mag Mell comes from Irish mythology translating to “A delightful or pleasant plain.” These young, bright space enthusiasts designed their space settlement as a pleasant place to live for up to 10,000 people. Each took turns presenting a different aspect of their design to ISDC attendees during the dinner talks on Saturday. I was struck by their optimism for the future and hopeful that they will be representing the next generation of space settlers.

Robotically 3D printed in-situ, Mag Mell would be placed in Ceres equatorial orbit and built using materials mined from that world and other bodies in the Asteroid Belt. The settlement was designed as a rotating half-cut torus with different angular rotation rates for the central hub and outer rim, featuring artificial 1G gravity and an Earth-like atmosphere. Access to the surface of the asteroid would be provided by a space elevator over 1000 km in length.

* St. Flannan’s College Space Settlement design team: Cian Pyne, Jack O’Connor, Adam Downes, Garbhán Monahan, and Naem Haq

Conceptual illustration of a habitat on Mars constructed from self-replicating greenhouses. Credits: GrowMars / Daniel Tompkins

Daniel Tompkins, an agricultural scientist and founder of GrowMars, presented his Expanding Loop concept of self replicating greenhouses which would be 3D printed in situ on the Moon or Mars (or in LEO). The process works by utilizing sunlight and local resources like water and waste CO2 from human respiration to grow algae for food with byproducts of bio-polymers as binders for 3D printing blocks from composite concretes. Tompkins has a plan for a LEO demonstration next year and envisions a facility eventually attached to the International Space Station. He calculates that a 4000kg greenhouse could be fabricated from 1 year of waste CO2 generated by four astronauts. An added bonus is that as the greenhouse expands, an excess of bioplastic output would be produced, enabling additional in-space manufacturing.

Diagram depicting GrowMars Expanding Loop algae growing process to create greenhouse blocks and byproducts such as proteins and fertilizer. Credits: GrowMars / Daniel Tompkins.
Illustration of a portion of the Spacescraper tethered ring from the Atlantis Project. Credits: Phil Swan

Phil Swan introduced the Atlantis Project, an effort to create a permanent tethered ring habitat at the limit of the Earth’s atmosphere, which he calls a Spacescraper.  The structure would be placed on a stayed bearing consisting of two concentric rings magnetically attached and levitated up to 80 km in the air.  In a white paper available on the project’s website, details of the force vectors for levitation of the device, the value proposition and the economic feasibility are described. As discussed during the talk at ISDC, potential applications include:

  • Electromagnetic launch to space
  • Carbon neutral international travel
  • Evacuated tube transit system
  • Astronomical observatories
  • Communication and internet
  • Solar energy collection for electrical power
  • Space tourism
  • High rise real estate

Phil Swan will be coming on The Space Show June 21 to provide more details.

Conceptual illustration of a Mars city design with dual centrifuges for artificial gravity. Credits: Kent Nebergall

Finally, the Chair of the Mars Society Steering committee and founder of MacroInvent Kent Nebergall, gave a presentation on Creating a Space Settlement Cambrian Explosion. That period, 540 million years ago when fossil evidence goes from just multicellular organisms to most of the phyla that exist today in only 10 million years, could be a metaphor for space settlement in our times going from extremely slow progress to a quick expansion via every possible solution. Nebergall suggests that we may be on the verge of a similar growth spurt in space settlement and proposes a roadmap to make it happen this century.

He envisions three settlement eras beginning with development of SpaceX Starship transportation infrastructure transitioning to robust cities on Mars with eventual para-terraforming of that planet. He also has plans for how to overcome some of the most challenging barriers – momentum and money. Stay tuned for more as Kent has agreed to an exclusive interview on this topic in a subsequent post on SSP as well as an appearance on The Space Show July 10th.

Posted on

NewSpace features the dawn of the age of space resources

Illustration showing concept of operations of the RedWater mining system for water extraction on Mars developed by Honeybee Robotics. Credits: Mellerowicz et al. via New Space

The editorial in the latest issue of New Space, coauthored by two of SSP’s favorite ISRU stars, Kevin Cannon and George Sowers, describes the dawning age of space resource utilization. Cannon, who guest edits this issue, and Sowers are joined by the rest of the leadership team of the graduate program in Space Resources at the The Colorado School of Mines: Program Director Angel Abbud-Madrid and professor Chris Dreyer. The program, created in 2017, has over 120 students currently enrolled. These are the scientists, engineers, economists, entrepreneurs and policymakers that will be leading the economic development of the high frontier, creating the companies and infrastructure for in situ resource utilization that will enable affordable and prosperous space settlement.

How can regolith on the Moon and Mars be refined into useful building materials? What are the methods for extracting water and oxygen from other worlds for life support systems and rocket fuel? Is it legal to do so? Will private property rights be granted through unilateral legislation? What will space settlers eat? The answers to all these questions and more are addressed in this issue, many of the articles free to access.

One of my favorite pieces, the source of this post’s featured image, is on the RedWater system for harvesting water on Mars. This technology, inspired by the proven Rodwell system in use for sourcing drinking water at the south pole, was developed by Honeybee Robotics, just acquired by Blue Origin earlier this year. End-to-end validation of the system under simulated Mars conditions demonstrated that water could be harvested from below an icy subsurface and pumped to a tank up on the surface.

We need to start thinking about these technologies now so that plans are ready for implementation once a reliable, affordable transportation system comes on line in the next few years led by companies such as SpaceX and others. Sowers has been working on thermal ice mining on cold worlds throughout the solar system for some time, predicting that water will be “the oil of space”. Cannon has been featured previously on SSP with his analytical tools related to lunar mining, the Pinwheel Magma Reactor for synthetic geology and plans for feeding millions of people on Mars.

Posted on

Crops in space: providing sustenance and life support for settlers

Roadmap for research and infrastructure development for growing crops in space for human sustenance and life support, from the ISS to Mars. Credits: Grace L. Douglas, Raymond M. Wheeler and Ralph F. Fritsche

Space settlement advocates know that we will have to take our biosphere with us to space to produce food, provide breathable air and recycle wastes. Completely closing the system, i.e. recycling everything is a huge technological challenge, especially on a small scale like what is planned for settlements in free space or on the surfaces of the Moon or Mars. Fortunately, there are plenty of raw materials in the solar system for in situ resource utilization so we can live off the land, so to speak, until our bioregenerative life support system efficiencies improve.

Early research into crop production in space has been performed on the ISS. But the road ahead for space agriculture in the context of life support systems needs careful planning to pave the way toward biologically self-sustaining space settlements. A team of scientists at NASA is working on a roadmap toward sustainability with a step-by-step approach to bioregenerative life support systems (BLSS) that will provide food and oxygen for astronauts during the space agency’s mission plans in the decades ahead. In a paper in the journal Sustainability they identify the current state of the art, resource limitations and where gaps remain in the technology while drawing parallels between ecosystems in space and on Earth, with benefits for both.

Simulation and modeling of BLSS concepts is important to predict their behavior and help inform actual hardware designs. A team at the University of Arizona performed a study recently analyzing the inputs and outputs of such a system to improve efficiencies and apply it to food production on Earth in areas challenged by resource limitations and food insecurity. Sustainable ecosystems for supporting humans on and off Earth have similar goals: minimizing growing space, water usage, energy needs and waste production while simultaneously maximizing crop yields. The team presented their findings in a paper presented at the 50th International Conference on Environmental Systems held last July. In the study, a model of an ecosystem was created consisting of various combinations of plants, mushrooms, insects, and fish to support a population of 8 people for 183 days with an analysis of total growing area, water requirements, energy consumption and total wastes produced. The study concluded that “In terms of resource consumption, the strategy of growing plants, mushrooms, and insects is the most resource-efficient approach.”

At the same conference, an update was provided on a Scalable, Interactive Model of an Off-World Community (SIMOC). SIMOC was described in a previous post on the Space Analog for the Moon and Mars (SAM) located at Biosphere 2 in Arizona. SIMOC is a platform for education meeting standards for student science curriculum. Pupils or citizen scientists can customize human habitats on Mars by selection of mission duration, crew size, food provisions as well as choosing types of plants, levels of energy production, etc.. Users gain an understanding of the complexity of a BLSS and the tradeoffs between mechanical and biological variables of life support for long duration space missions. There is much to be learned on the limitations and stability of closed biospheres, as discussed last year.

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 stability. Credits: Biosphere 2 / University of Arizona

Across the Pond, our European friends at LIQUIFER Systems Group are working on greenhouses for the Moon and Mars derived from the EDEN ISS simulation facility in Antarctica.

A BLSS based on plant biology could be augmented with dark ecosystems, the food chain based on bacteria that are chemotrophic, i.e. deriving their energy from chemical reactions rather then photosynthesis, which could significantly reduce the inputs of energy and water.

A concept for a lunar farm called Lunar Agriculture, Farming for the Future was published in 2020 by an international team of 27 students participating in the Southern Hemisphere Space Studies Program at the International Space University.

Layout of a potential subsurface lunar farm. Credits: International Space University and University of South Australia

As a treat to cap off this post, a retired software engineer and farmer named Marshall Martin living in Oklahoma provided his perspective on crops in space on The Space Show recently. A frequent caller to the program, this was his first appearance as a guest where, like the NASA team mentioned earlier, he recommends a phased approach to space farming starting with small orbital facilities, testing inputs and outputs as we go, to ensure the economics pay off at each stage of our migration off Earth. He even envisions chickens and goats as sources of protein and milk, although the weight limitations for inclusion of these animals in space-based ecosystems may not be possible for quite some time. Its unlikely that cows will ever make it to space but cultured meat production is a real possibility for the carnivores among us which is being studied by ESA.

Cattle in the cargo bay of the Firefly-class transport spaceship Serenity. Cows probably won’t make it to space because of weight, volume and resource limitations but cultured meat is a real possibility. Image from the television series Firefly. Credits: Josh Whedon/ Mutant Enemy, Inc. in associations with Twentieth Century Fox Television

Finally, for those thinking long term of eventual settlement of the galaxy, there are even some people modeling life support systems for interstellar arks.

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

Posted on

Charon: a reusable single-stage to orbit shuttle for Mars

Conceptual illustration depicting the Charon single-stage to Mars orbit mission architecture. Credits: Jérémie Gaffarel et al.* – image from Graphical Abstract with addition of text.

In the next few decades a settlement on Mars will be established, either by Elon Musk or other spacefaring entities (or both). To enable an economically viable supply chain to support a prosperous colony on Mars, an affordable and sustainable transportation system will be needed. Musk is designing Starship for what he originally called an interplanetary transportation system. But his design is just the first step and is expected to evolve over time. As originally conceived Starship may not make long term economic sense for launch from Earth, travel across interplanetary space, landing on Mars, lift off again and finally, return and safe landing on Earth. Even though the Starship User Guide says the the vehicle is designed to carry more than 100 tons to Mars, the enormous amount of cargo and crew required to be transported to support a prospering and sustainable Martian colony if done only with repeated Starship launches directly from Earth will likely be too expensive.

A better approach might be to limit Starship to an in-space transportation system which cycles back and forth between Earth and Mars orbits without a (Mars) landing capability. Not knowing how Starship may evolve, this could be a starting point. Eventually, a more efficient interplanetary transportation system may be an Aldrin cycler. Either scenario would require a shuttle at Mars for delivery of payloads from low orbit to the surface and back to space again. A team* at Delft University of Technology, The Netherlands has come up with a design for a reusable singe-stage to orbit vehicle they call Charon that would reliably address this final leg of the Mars supply chain. They described the mission architecture in an article in the journal Aerospace last year.

The team identified 80 key design requirements for Charon, but three stood out as the most important. At the top of the list was the capability of transporting 6 people and 1200 kg of cargo to and from low Mars orbit. Next, any consumables needed for the vehicle would have the capability of being produced in situ on Mars. Finally, because of the human rating, the reliability of the system would have to be high – with loss of crew less than 0.5% or 1 out of 270, which is equivalent to SpaceX’s Crew Dragon.

With safety being a high priority an abort subsystem is included to address each anticipated flight phase and the associated abort modes. The SpaceX Starship design does not have an abort system, so the authors believe that Charon would be safer for launch from Mars given the high flight rate anticipated to and from Mars low orbit. They suggest that Starship be limited to launch from Earth and interplanetary transportation to Mars orbit.

Cutaway illustration of the layout of the Charon vehicle adapted from Figure 5 in article. Credits: Jérémie Gaffarel et al.*

Cutaway view of the capsule adapted from Figure 4 in article. Credits: Jérémie Gaffarel et al.*

Significant infrastructure will be needed on Mars to support operations, especially in situ resource utilization for production of methane and oxygen for Charon’s propulsion system. This pushes out the timeline for implementation a few decades (to at least 2050) when a Mars base is expected to be well established with appropriate power sources and equipment to handle mining, propellant manufacturing, maintenance, communications and other needed facilities.

Upon a thorough analysis of Charon’s detailed design, reliability and budgets the team concluded that “The program for its development and deployment is technologically and financially feasible.”

* Gaffarel, Jérémie, Afrasiab Kadhum, Mohammad Fazaeli, Dimitrios Apostolidis, Menno Berger, Lukas Ciunaitis, Wieger Helsdingen, Lasse Landergren, Mateusz Lentner, Jonathan Neeser, Luca Trotta, and Marc Naeije. 2021. “From the Martian Surface to Its Low Orbit in a Reusable Single-Stage Vehicle—Charon” Aerospace 8, no. 6: 153. https://doi.org/10.3390/aerospace8060153

Posted on

Update on the Photonic Laser Thruster and the interplanetary Photonic Railway

Diagram depicting the layout of the Photonic Laser Thruster (PLT). Credits: Young K. Bae, Ph.D.

SSP reported last year on the promise of an exciting new Photonic Laser Thruster (PLT) that could significantly reduce travel times between the planets and enable a Phonic Railway opening up the solar system to rapid exploration and eventual settlement. The inventor of the PTL, Dr. Young K. Bae has just published a paper in the Journal of Propulsion and Power (behind a paywall) that refines the mathematical underpinnings of the PLT physics and illuminates some exciting new results. Dr. Bae shared an advance copy of the paper with SSP and we exchanged emails in an effort to boil down the conclusions and clarify the roadmap for commercialization.

Illustration of a Photonic Railway using PLT infrastructure for in-space propulsion established at (from right to left, not to scale) Earth, Mars, Jupiter, Pluto and beyond. Credits: Young K. Bae.

In the new paper, Dr. Bae refines his rigorous analysis of the physics behind the PLT confirming previous projections and discovering some exciting new findings.

As outlined in the previous SSP post linked above, the PLT utilizes a “recycled” laser beam that is reflected between mirrors located at the power source and on the target spacecraft. Some critical researchers have argued that upon each reflection of the beam off the moving target mirror, there is a Doppler shift causing the photons in the laser light to quickly lose energy which could prevent the PLT from achieving high spacecraft velocities. The new paper conclusively proves such arguments false and confirming the basic physics of the PLT.

There were two unexpected findings revealed by the paper. First, the maximum spacecraft velocity achievable with the PLT is 2000 km/sec which is greater than 10 times the original estimate. Second, the efficiency of converting the laser energy to the spacecraft kinetic energy was found to approach 50% at velocities greater than 100 km/s. This is surprisingly higher than originally thought and is on a par with conventional thrusters – but the PLT does not require propellent. These results show conclusively that once the system is validated in space, the PLT has the potential to be the next generation propulsion system.

I asked Dr. Bae if anything has fundamentally changed recently in photonic technology that will bring the PLT closer to realization. He said that the interplanetary PLT can tolerate high cavity laser energy loss factors in the range of 0.1-0.01 % that will permit the use of emerging high power laser mirrors with metamaterials, which are much more resistant to laser induced damage and are readily scalable in fabricating very large PLT mirrors.

With respect to conventional thrusters, he said the PLT can be potentially competitive even at low velocities on the order of 10 km/s, especially for small payloads. This is because system does not use propellant which is very expensive in space and because the PLT launch frequency can be orders of magnitude higher than that of conventional thrusters. Dr. Bae is currently investigating this aspect of the system in terms of space economics in depth.

The paper acknowledges that one of the most critical challenges in scaling-up the PLT would be manufacturing the large-scale high-reflectance mirrors with diameters of 10–1000m, which will likely require large-scale in-space manufacturing. Fortunately, these technologies are currently being studied through DARPA’s NOM4D program which SSP covered previously and Dr. Bae agreed that they could be leveraged for the Photonic Railway.

Artist’s concept of projects, including large high-reflectance mirrors, which could benefit from DARPA’s (NOM4D) plan for robust manufacturing in space. Credits: DARPA

I asked Dr. Bae about his timeline and TRL for a space based demo of his Sheppard Satellite with PLT-C and PLT-P propellantless in-space propulsion and orbit changing technology. He responded that such a mission could be launched in five years assuming there were no issues with treaties on space-based high power lasers. There is The Treaty on the Prevention of the Placement of Weapons in Outer Space but I pointed out that the U.S. has not signed on to this treaty. Article IV of the Outer Space Treaty states that “…any objects carrying nuclear weapons or any other kinds of weapons of mass destruction…” can not be placed in orbit around the Earth or in outer space. Dr. Bae said “We can argue that the [Outer Space] treaty regulation does not apply to PLT, because its energy is confined within the optical cavity so that it cannot destroy any objects.  Or we can design the PLT such that its transformation into a laser weapon can be prevented.”

He then went on to say: “For space demonstration of PLT spacecraft manipulation including stationkeeping, I think using the International Space Station platform would be one of the best ways … I roughly estimate it would take $6M total for 3 years for the demonstration using the ISS power and cubesats. The Tipping Point [Announcement for Partnership Proposals] would be a good [funding mechanism] …to do this.”

Once the technology of the Photonic Railway matures and is validated in the solar system Dr. Bae envisions its use applied to interstellar missions to explore exoplanets in the next century as described in a 2012 paper in Physics Procedia.

Conceptual illustration of the Photonic Railway applied to a roundtrip interstellar voyage to explore exoplanets around Epsilon Eridani. This application requires four PLTs: two for acceleration and two for deceleration. Credits: Young K. Bae

Be sure to listen live and call in to ask Dr. Bae your questions about the PLT in person when he returns to The Space Show on March 29th.

Posted on

Dark ecosystems for food production in space

Artist concept of industrial hubs of circular food production including vertical farming, bioreactors, greenhouses, water treatment and energy production. The same technology has duel use and could be leveraged for life support systems in space settlements. Credits: Mark Goerner / Orbital Farm

Typical plans for space settlements include greenhouses for growing plants as a source of food as well as a key component of ecological closed life support systems to help produce air and recycle water. There are efforts to make these space farms as compact and efficient as possible utilizing hydroponics and LED lighting. But the energy, volume, water and labor requirements can still be a challenge. A new approach is described in a paper in New Space by Michael Nord and Scot Bryson that is based on Earth’s dark ecosystem, the food chain based on bacteria that are chemotrophic, i.e. deriving their energy from chemical reactions rather then photosynthesis. An example of these type of organisms are bacteria that live near volcanic sulfur vents at the bottom of the ocean. They synthesize organic molecules from hydrogen sulfide, carbon dioxide and oxygen which in turn nourish giant tube worms.

Giant tube worms nourished by organic molecules synthesized by chemotrophic bacteria near deep undersea sulfur vents. Credits: Biology Dictionary

“Earth’s dark ecosystem affords us an elegant solution.”

This is not new technology. Fermentation is an example of this biological process which humans have been using for thousands of years in the production of food and drink. NASA explored this option in the 1960s in their plans for sources of food to sustain astronauts on long duration space flights. Synthetization of “single-celled proteins” showed promise for astronaut sustenance but NASA’s priorities shifted after Apollo putting less emphasis on manned spaceflight leading to funding cuts, which put these efforts on hold.

Fast forward to today, there are many companies focusing on using dark ecology as an alternative source of protein both for an ever increasing human population and for animal agriculture. The single-celled proteins are produced by fermentation in bioreactors to produce products mainly used in animal feed but at least one firm, Quorn, is focused on human consumption.

Mycoprotein for human consumption produced by fermentation of the fungus Fusarium venenatum. Credits: Quorn

Others in both government and industry are transitioning Earth’s agricultural approach to a circular economy for food, where food waste is designed out, food by-products are re-used at their highest value, and food production regenerates rather than degrades natural systems. Innovations by companies involved in this type of farming here on Earth have direct applications in bioregenerative life support systems in space. Orbital Farm, who’s CEO Scot Bryson coauthored the paper, is one such company exploring commercialization opportunities in this field.

The authors performed an analysis of energy inputs and material flows for conventional photosynthetic food production when compared to a dark ecosystem and found that the latter is 100 times more efficient in water and energy use, and 1000 times better in terms of volume. But that is not all. There is an added benefit in that “…the very same organisms can be engineered to make pharmaceuticals, plastics, and a variety of other useful complex organic compounds.”

The advantages for space settlement are clear. Although photosynthetic plant growth will play a role in life support systems including the added benefit to humans of the aesthetic value of living among plants, dark ecology can augment food from photosynthetic plants with efficient and sustainable protein production.

“…for bulk production of calories, chemotrophic organisms have enormous efficiencies over production with staple crops, which will be nearly impossible to ignore for mission designers.”

Posted on

Moon-Mars dumbbell variable gravity research facility in LEO

Conceptual illustration depicting the deployment sequence of a LEO Moon-Mars dumbbell partial gravity facility serviced by SpaceX’s Starship. Left: Starship payloads being moored by a robot arm. Center: 1.6 m ID inflatable airbeams (yellow) play out from spin access and mate with dumbbell end modules. Rectangular solar arrays deploy by hanging at either end as spin is initiated via thrusters at Mars module. Right: Full deployment with Starship and Dragon docked at spin axis hub. Credits: Joe Carroll via The Space Review

There may be no single human factor more important to understand on the road to long term space settlement than determination of the gravity prescription (GRx) for healthy living in less than Earth normal gravity. What do we mean by the GRx? With over 60 years of human space flight experience we still only have two data points for stays longer than a few days to study the effects of gravity on human physiology: microgravity aboard the ISS and data here on the ground. Based on medical research to date, we know that significant problems arise in human health after months of exposure to microgravity. To name a few, osteoporosis, immune system degradation, diminished muscle mass, vision problems due to changes in interocular pressure and cognitive impairment resulting memory loss and lack concentration. Some of these problems can be mitigated with a few hours of daily exercise. But recovery upon return to normal gravity takes considerable time and we don’t know if some of these problems will become irreversible after longer term stays. We have virtually no data on human health at gravity levels of the Moon and Mars, as shown in this graph by Joe Carrol:

Graph of the correlation between human health vs gravity showing the two data points where we have useful data. Whether the relationship is a linear function or something more complex is an unknown of great importance for space settlement. Credits: Joe Carrol presentation at Starship Congress 2019 and Jon Goff post on Selenium Boondocks Nov 29, 2005

The more important question for permanent space settlements is can humans have babies in lower gravity? If we go by the National Space Societies’ definition, an outpost will never really become a permanent space settlement until it is “biologically self-sustaining”. We evolved over millions of years at the bottom Earth’s gravity well. How will amniotic fluid, changes in cell growth, fetal development and human embryos be affected during gestation under lower gravity conditions on the Moon or Mars? There are already indications that problems will arise during mammalian gestation, at least in microgravity as experienced aboard the ISS.

To answer these questions, Joe Carroll suggests the establishment of a crewed artificial gravity research facility in LEO which he described last month in an article in The Space Review. He proposes a Moon-Mars dumbbell with nodes spinning at different rates to simulate gravity on both the Moon and Mars, which covers most of the planetary bodies in the solar system where settlements would be established if not in free space. The facility could be launched and tended by SpaceX’s Starship once the spacecraft is flight worthy in the next few years in parallel with Elon Musk’s plans to establish an outpost on Mars. Musk may even want to fund this facility to inform his long term plans for communities on Mars. If his goal is for the humanity to become a multiplanetary species, surely will want to know if his settlers can have children.

Carroll’s design connects the Moon and Mars modules with radial structures called “airbeams” which will allow crew to access the variable gravity nodes in a shirtsleeve environment. The inflatable members are composed of polymer fiber fabric which can be easily folded for storage in the Starship payload bay. Crews would be initially launched aboard Dragon until the Starship is human rated.

“Eventually, rotating free-space settlements will get massive enough to use other shapes, but dumbbells plus airbeams seem like the key to useful early ones.”

The paper addresses details on key operating concepts, docking procedures, emergency protocols, and the implications for long term settlement in the solar system.

There may even be a market for orbital tourism to experience lower gravity that could make funding for the facility attractive to space venture capitalists, especially if it is located in an equatorial orbit shielded from ionizing radiation by the Earth’s magnetic fields. As the technology matures, older tourists may even want to retire in orbital communities that offer the advantage of lower gravity as their bodies become frail in their golden years.

Humankind’s expansion out into the solar system depends on where we can survive and thrive in a healthy environment. If ethical clinical studies on lower mammals in a Moon/Mars dumbbell clears the way for a healthy life in lunar gravity then we can expand out to the six largest moons including our own plus Mars. If the data shows we need at least Mars gravity, then the Red Planet or even Mercury could be potential sites for permanent settlement. But if nothing below Earth normal gravity is tolerable, especially for mammalian gestation, it may be necessary to build ever larger rotating O’Neillian free space settlements to expand civilization across the solar system. There are vast resources and virtually unlimited energy if we need to do that. But it will take considerable time and careful planning to establish the vast infrastructure needed to build these settlements. If human physiology is constrained by Earth’s gravity then space settlers will want to know this information soon so that the planning process can be integrated into space development activities about to unfold on the Moon and beyond. If Musk finds out that Mars inhabitants cannot have children and wants to establish permanent communities beyond Earth, would he change course and switch to O’Neillian free space settlements?

“If we do need sustained gravity at levels higher than that of Mars, it seems easier to develop sustainable rotating settlements than to terraform any near-1g planet.”

Listen to Joe Carroll answer my questions about his Moon/Mars dumbbell facility from earlier this month on this archived episode of The Space Show.

Posted on

Robotic production of underground habitats on Mars

An underground habitat on Mars excavated by autonomous rovers reinforced with 3D printed concrete from Martian regolith. Credits Henriette Bier et al.* / Technical University Delft

A team* of researchers at Technical University Delft (TUD) in the Netherlands led by Henriette Bier published a paper last year describing a method for robotically excavating and building structures in cavities below the surface of Mars to provide living spaces for colonists that would be both protected from radiation and thermally insulated from extreme cold. The process would be initiated by autonomous digging rovers hogging out tunnels in a spiral pattern and utilizing the excavated regolith to create concrete for the next step. Using a process developed by TUD called Design-to-Robotic-Production (D2RP) the concrete would be extruded by a 3D printer to reinforce the tunnel walls. Called “Scalable Porosity” TUD has pioneered this process for Earth based architectural applications.

The assumption is that the generated structure is a structurally optimized porous structure, which has increased insulation properties … and requires less material and printing time.

Credits: Technical University Delft

Once structurally sound, the material between the tunnels would be removed to create habitat spaces to be filled by inflatable structures made from materials also sourced in situ.

Although not addressed in detail in the article the authors propose that electrical power be provided by a combination of solar energy and an innovative kite based platform, a highly efficient airborne energy system based on soft wing technology pumped by persistent winds at high altitudes. TUD pioneered this renewable energy technology based on inflatable membrane wings tethered to a ground based generator through its Kite Power research group. A startup called Kitepower B.V. was spun off as a result of this research to commercialize the technology hear on Earth.

Credits: Kitepower B.V.

The D2RP process is data driven and

“…integrates advanced computational design with robotic techniques in order to produce architectural formations by directly linking design to building production.”

For example, the habitat will require a life support system which includes a plant cultivation facility, water recycling and oxygen production controls. These design inputs are coded in the 3D printing program to fabricate the structure around sensor-actuator systems that regulate plant growth and wiring for control mechanisms.

TUD’s goal is to develop a fully self sufficient D2RP system for fabricating subsurface settlements on Mars via ISRU.

* TUD Team members: Henriette Bier, Edwin Vermeer, Arwin Hidding, Krishna Jani

Posted on

Starship changes the space settlement paradigm

Artist rendering of an earlier version of Starship (formerly BFR, Interplanetary Transport System) approaching Mars. Credits: SpaceX

A mission architecture for Starship is described in a preprint open access article published online December 2 to be released in the next issue of the New Space Journal. The paper lays out a proposed strategy for using the yet to be validated SpaceX reusable spacecraft to establish a self sustaining colony on Mars. The authors* are a mix of space practitioners from NASA, the space industry and academia. No doubt Elon Musk may be thinking along these lines as he lays his company’s plans to assist the human race in becoming a multi-planet species.

Starship is a game changer. It is being designed from the start to deposit massive payloads on The Red Planet. It will be capable of delivering 100 metric tons of equipment and/or crew to the Martian surface, and after refueling from locally sourced resources, returning to Earth. This capability will not only enable extensive operations on Mars, it will open up the inner solar system to affordable and sustainable colonization.

Some of the assumptions posited for the mission architecture are based on Musk’s own vision for his company’s flagship space vehicle as articulated in the New Space Journal back in 2017, namely that two uncrewed Starships would initially be sent to the surface of Mars with equipment to prepare for a sustainable human presence.

“These first uncrewed Starships should remain on the surface of Mars indefinitely and serve as infrastructure for building up the human base.”

The initial landing sites will be selected based on where the water is. The priority will be finding and characterizing ice deposits so that humans will eventually be able to locally source water for life support and to produce fuel for the trip home. The automated payloads of these initial missions will be mobile platforms similar in design to equipment planned for upcoming robotic missions to the Moon in the next couple of years. One such spacecraft, the Volatiles Investigating Polar Exploration Rover (VIPER) is discussed with its suite of instruments that will be used to assess the composition, distribution, and depth of subsurface ice to inform follow-on ISRU operations.

“The use of water ice for ISRU has been determined as a critical feature of sustainability for a long-term human presence on Mars.”

VIPER Searches for Water Ice on the Moon
Conceptual depiction of the NASA VIPER rover planned for delivery to the Moon’s south pole in late 2023. A mobile platform with a similar suite of instruments based on this design could be launched to Mars aboard Starship. Credits: NASA

To harvest water from subsurface ice the authors suggest using proven technology such as a Rodriguez Well (Rodwell). In use since 1995, a Rodwell has been providing drinking water for the U.S. research station in Antarctica. The U.S. Army Engineer Research and Development Center’s (ERDC) Cold Region Research and Engineering Laboratory (CRREL)  has been working with NASA to prove the technology for use in space in advance of a human outpost on Mars.

Diagram depicting how a Rodriquez Well works. Credits: U.S. Army Engineer Research and Development Center

“Rodwell systems are robust and still in routine use in polar regions on Earth.”

The next order of business is power generation. The authors suggest using solar power as a first choice because the technology readiness level is the most mature at this time. Autonomous deployment of a photovoltaic solar array would be carried out on the initial uncrewed missions. But due to frequent dust storms that could diminish the array reliability, nuclear power may be a more appropriate long term solution once space based nuclear power is proven. NASA’s Glenn Research center is working on Fission Surface Power with plans for a lunar Technology Demonstration Mission in the near future. A solid core nuclear reactor is also an option as the technology is well understood.

These initial missions will robotically assess the Martian environment at the landing sites to inform designs of subsequent equipment to be delivered by crewed Starship missions in future launch windows occurring every 26 months. Weather monitoring will be performed as well as measurements of radiation levels and geomorphology to inform designs of habitats and trafficability. Remotely controlled experiments on hydroponics will also be performed to understand how to produce food. Testing will be needed on excavation, drilling, and construction methods to provide data on how infrastructure for a permanent colony will be robustly designed.

Starship’s ample payload capacity will allow prepositioning of supplies of food and water to support human missions before self sustaining ISRU and agriculture can be established. Communication equipment will be deployed and landing sites prepared for the arrival of people. Much of these activities will be tested on the Moon ahead of a Mars mission.

Production of methane and oxygen in situ on Mars will enable refueling of Starship for the trip home, as envisioned in 1990 by Robert Zubrin and David Baker with their Mars Direct mission architecture. Zubrin’s Pioneer Astronautics may even play a role through provision of equipment for ISRU as they are already working on hardware that could be tested on the Moon soon. One could envision a partnership between Zubrin and Musk as their organizations have common visions, and Zubrin has written about the transformative potential of Starship. When people arrive on Starship during a subsequent launch window after the placement of uncrewed vehicles, further testing of ISRU and life support equipment will be performed with humans in the loop to validate these technologies that will enable Mars settlements to sustain themselves.

If Musk is successful in establishing a permanent self-sustaining colony on Mars will it be a true settlement? The National Space Society in their definition says that a space settlement “..includes where families live on a permanent basis, and…with the goal of becoming…biologically self-sustaining…”, i.e. capable of human reproduction. The definition is agnostic as to if the settlement is in space or on a planetary surface. Musk wants to established cities on the planet housing millions of people by mid century. But does this make sense if settlers can’t have healthy children in the lower gravity of Mars? SSP explored this question in a recent post. Hopefully, once Starship becomes operational, an artificial gravity research facility in LEO will be high on Musk’s priority list to answer this question before he gets too far down the Martian urban planning roadmap. Would he ever consider a change in space settlement strategy in favor of O’Neill type free space colonies? Starship could certainly help facilitate the realization of that vision.

If all goes according to plan, SpaceX will attempt the first orbital flight of a Starship prototype sometime next year, which also happens to be when the next launch window opens up for trips to Mars. Obviously, nothing in rocket development goes according to plan, so the initial flight ready design is at least a year away optimistically. And we know Musk’s timelines are notoriously aspirational. As ambitious as Musk is in driving his company toward the goal of colonizing Mars, it seems unlikely that an initial uncrewed mission with all its flight ready automated hardware as described above could be ready by the next launch window in 2024. But what about 2026? NASA’s current plans for return to the Moon call for a human rated version of Starship as a lunar lander “…no earlier then 2025”. However, Japanese billionaire Yusaku Maezawathe’s Dear Moon mission sending 8 crew members around Luna with a crewed Starship is still planned for 2023. A lot of details are yet to be worked out and we still have not covered the topic of Planetary Protection nor the granting of a launch license to SpaceX by the FAA, but could a Starship human mission to Mars take place in 2028? Let me know what you think.

“The SpaceX Starship vehicle fundamentally changes the paradigm for human exploration of space and enables humans to develop into a multi-planet species.”

* Authors of Mission Architecture Using the SpaceX Starship Vehicle to Enable a Sustained Human Presence on Mars Jennifer L. Heldmann, Margarita M. Marinova, Darlene S.S. Lim, David Wilson, Peter Carrato, Keith Kennedy, Ann Esbeck, Tony Anthony Colaprete, Rick C. Elphic, Janine Captain, Kris Zacny, Leo Stolov, Boleslaw Mellerowicz, Joseph Palmowski, Ali M. Bramson, Nathaniel Putzig, Gareth Morgan, Hanna Sizemore, and Josh Coyan

Posted on

Making the MMOST of ISRU for the Moon and Mars

Conceptual illustration of the Lunar OXygen In-situ Experiment (LOXIE) Production Prototype. Credits: Mark Berggren / Pioneer Astronautics

Here’s a novel way to produce both oxygen and steel in situ on the Moon and eventually on Mars. Under a NASA SBIR Phase II Sequential Contract, Pioneer Astronautics along with team members Honeybee Robotics and the Colorado School of Mines are developing what they call Moon to Mars Oxygen and Steel Technology (MMOST), an integrated system to produce metallic iron/steel and oxygen from processed lunar regolith.

In a presentation at a meeting of the Lunar Surface Innovation Consortium last month, Mark Berggren of Pioneer Astronautics gave an update on the team’s efforts. Progress has been made on several key processes under development as part of the overall manufacturing flow. Output products will include oxygen for either life support or rocket fuel oxidizer and metallic iron for additive manufacturing of lunar steel components.

MMOST process flow diagram. Credits: Mark Berggren / Pioneer Astronautics

The immediate next steps for the MMOST development program will be continual refinement of each process module, protocols for minimization of power requirements, demonstration of LOXIE in a vacuum environment and then optimization of mass, volume and power specifications for a scaled-up system toward flight readiness hardware.

Potential follow-on activities may include a robotic sub-scale LOXIE lunar flight experiment that could be sent to the Moon via a Commercial Lunar Payload Services (CLPS) lander. As part of the Artemis program crews could possibly demonstrate a pilot unit to validate manufacturing in the lunar environment. If successful, a full scale MMOST commercial system could come next in support of lunar base operations as part of a cis-lunar economy.