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A vision for industry on the Moon

Credits: Michael Nayak / Air University Press

Air University Press, the academic publisher of the U.S. Air Force, this last July published the The Commercial Lunar Economy Field Guide: A Vision for Industry on the Moon in the Next Decade, edited by Michael Nayak. The document presents a revolutionary blueprint for the transformation of the Moon from a scientific curiosity into a vibrant, self-sustaining industrial marketplace in the 2030s. Central to this vision is DARPA’s 10-Year Lunar Architecture (LunA-10) initiative, which seeks to establish integrated, interoperable infrastructure that lowers the barrier to entry for all lunar users. This may help with execution of the Trump Administration’s recent Executive Order (EO) which aims to establish a space policy “… that will extend the reach of human discovery, secure the Nation’s vital economic and security interests, unleash commercial development, and lay the foundation for a new space age”. The Field Guide and the EO are not perfectly aligned but the former provides an architectural blueprint to implement the strategic mandate prescribed by latter. The EO provides the authority and deadlines (e.g., returning to the Moon by 2028), while the Field Guide provides the technical and economic pathways (LunA-10) to achieve those goals in a manner that will add value for taxpayers. While diving into the specifics of the Field Guide, along the way I’ll highlight how it will help implement the EO.

A Strategic Vision Beyond Unsustainable Symbolism

For decades, lunar exploration has followed a “Flags and Footprints” paradigm—symbolic, government-funded missions that are entirely self-reliant, bringing every gram of power, water, and data storage from Earth. The Field Guide argues that this approach, while scientifically valuable and a display of national pride, is economically unsustainable at the current “million-dollar-per-kilogram” cost of delivery. This is in alignment with the EO which calls for enhancing cost-effectiveness of exploration architectures while establishing initial elements of a permanent lunar outpost by 2030 to ensure a sustained American presence on the Moon, which will lay the groundwork for the exploration of Mars.

The Role of LunA-10

LunA-10 serves as a catalyst to seed the foundational nodes of a future economy on the Moon and in cislunar space. Similar to how DARPA fostered development of the internet and GPS, LunA-10 identifies “scalable nodes” where government investment can accelerate commercial capability. The goal is to move toward a model where NASA and commercial industry can purchase utilities—like power and data—as services, rather than owning the hardware.

Four Economic Ages of the Moon

The Field Guide identifies four distinct stages of development for the lunar economy:

  1. The Exploration Age (2025–2030): Characterized by one-of-a-kind, government-backed missions. Infrastructure is limited, confined to individual landers which are non-extendable.
  2. The Foundational Age: An era of “trail-building” where lunar surface transportation infrastructure is built out and users begin to subscribe to pilot services for power and communications.
  3. The Industrial Age (Target: 2035): Scaling through commoditization. Multi-service hubs provide consolidated thermal and power management, and large-scale manufacturing begins.
  4. The Jet Age: A state of self-sufficiency where In-Situ Resource Utilization (ISRU) will produce services such a propellent depots (lunar hydrogen and oxygen) to enable frequent, low-cost “rocket hop” transport across the lunar surface, servicing permanent settlements and supporting missions headed for deep space.

Pillars of Commercial Lunar Infrastructure

To achieve this vision, the Field Guide details several critical technology sectors that must transition from their experimental phases to full scale industrialization.

Power and Thermal as a Service

In the Exploration Age, not being able to survive the 14-day lunar night is a primary mission-killer. LunA-10 proposes Infrastructure Hubs—massive solar power towers, some taller than the Statue of Liberty, placed at the peaks of eternal light at the Moon’s south pole, a concept that SSP has explored previously. Here is where the Field Guide diverges a bit from the EO, as the latter calls for surface nuclear reactors as a source of reliable power, prioritizing this initiative to be implemented by 2030. The authors of the Lunar Power chapter were operating under the assumption that NASA’s nuclear Fission Surface Power project would not produce hardware soon based on current TRLs, so this source of power was outside the LunA-10 timeline. Of course solar power could be complementary to nuclear power sources. With this approach these hubs would include:

  • Multi-Service Nodes: The power towers do more than collect solar energy; they serve as “Swiss army knives,” on the Moon providing wireless power transmission, communication relays, and hosting Positioning, Navigation, and Timing (PNT) signals.
  • Thermal Microgrids: Just as Earth-based buildings use central HVAC systems, lunar thermal hubs will manage heat for multiple users. They can recycle waste heat from high-energy activities (like mining) to keep nearby robotic assets warm during the lunar night, significantly reducing the mass each mission must carry for thermal survival. This aligns with the EO’s call to deploy nuclear reactors on the Moon which will need to dissipate waste heat that can be put to use.

Logistics: The Lunar Rail Network

Transportation is the lifeblood of any economy. Initially, lunar rovers will be slow and inefficient; moving the cargo of a single heavy lander over long distances could take thousands of hours.

  • The Lunar Railroad: The Field Guide details a plan for a lunar rail network that dramatically increases the speed and volume of cargo transport.
  • Multi-Use Corridors: These rail lines would serve as integrated infrastructure conduits. Alongside the tracks, corridors would include wired power lines, data cables, and pipelines for gas and/or fluid transport. This “bundling” of services reduces the amortized cost for every company operating along the route.

Mining and the Metal Ecosystem

Sustainable settlement requires moving away from Earth-dependency through ISRU.

Conceptual illustration of the Lunar OXygen In-situ Experiment (LOXIE) Production Prototype, part of the Pioneer Astronautics (now part of Voyager Space Holdings) MMOST system. Credits: Mark Berggren / Pioneer Astronautics
  • The Circular Economy: The vision is a “reduce, reuse, recycle” ecosystem where expended rocket stages or other used assets are repurposed for storage and scrap metal is forged into new products on-site.

Orbital Infrastructure: Cislunar Supply Hubs

The economy extends beyond the Moon’s surface into cislunar space.

  • Space Harbors: Orbital aggregation hubs would act as deep-space analogs to terrestrial maritime ports hosting multiple value streams. Services would include rocket gas stations featuring robotic propellent transfer of stored hydrogen, oxygen, and methane; consolidated edge computing centers providing high-performance computing as a service such as autonomous docking calculations or mineral analysis by the hub’s more powerful servers; commodity sharing allowing arriving spacecraft to plug into the harbor to share excess solar power or fuel. By centralizing these activities, a space harbor would lower the mass of payloads a company must launch from Earth, effectively lowering the barrier to entry for any new commercial lunar venture. Arkisys has already begun to develop this type of infrastructure with The Port.
Conceptual illustration of The Port, a modular orbital platform under development by Los Alamitos, California-based Arkisys that will provide services for space assets such as refueling, battery recharging, thruster installation, repair, etc., laying the ground work for large-scale space harbors. Credit: Arkisys
  • Satellite “Retirement”: This model moves away from the “one-and-done” satellite paradigm toward a symbiotic system where older assets are repurposed as sharable resources contributing to the growth of the hub.

Economic and Legal Enablers

The Field Guide emphasizes that technology alone cannot build an economy; a transparent and predictable market framework will be needed.

Property Rights and Law

Under current international law (i.e. the Outer Space Treaty), nations cannot “own” the Moon. However, the Field Guide argues for “Continued Use” and “Allocated” rights, where companies can have exclusive control over the specific resources they extract and the infrastructure they build. The Artemis Accords provide the foundation for global consensus on these principles.

The Commodities Exchange and Board of Trade

To attract serious private capital, the Moon needs market transparency. The Field Guide recommends establishing a Space Commodities Exchange and a Lunar Board of Trade to define the quality and value of lunar resources like oxygen and regolith. This would allow for trading, hedging, and financing similar to terrestrial commodities like gold or oil.

Interoperability via the LOGIC Consortium

A major risk to a nascent economy is vendor lock-in where different companies’ hardware cannot communicate or share power without significant switching costs. To prevent this, DARPA established the Lunar Operating Guidelines for Infrastructure Consortium (LOGIC). LOGIC focuses on creating voluntary consensus standards for docking ports, power connectors, and communication protocols, ensuring the Moon becomes an open platform rather than a fragmented collection of proprietary systems.

Artist’s concept of commercial lunar infrastructure that would benefit from accelerating interoperability standards via LOGIC. Credits: DARPA

The Path to 2035

The Commercial Lunar Economy Field Guide concludes that while the engineering challenges of the Moon are “DARPA-hard,” they are solvable. By 2035, the goal is to reach break-even where the economy becomes self-sustaining and the risk for private investors is sufficiently lowered.

Successfully building this infrastructure will do more than just unlock the Moon; it will provide the operational experience, fuel and infrastructure (via ISRU) necessary for humanity to expand throughout the Solar System and eventually, to the stars. The Moon will no longer be just a destination for flags and footprints, but a key stepping stone on the path to becoming a spacefaring civilization.

Execution of the EO in Alignment with the Field Guide

To implement the Executive Order using the principles of the Field Guide the following actions should be prioritized with the caveat that the deadlines specified in the EO will be challenging to meet using many of the technologies in the Field Guide, given they’re current TRLs. Still, regardless of aspirational timelines that may be pushed out, the actions below will ensure that when commercial lunar development comes together in the 2030s, it will be cost effective and sustainable.

Action 1: Immediate Transition to Lunar Commodity Contracts

  • The Problem: Procurement of traditional government-owned hardware is slow and expensive.
  • Implementation: Within the 180-day window mandated by the EO, NASA and the Dept. of Commerce should issue Multi-Service RFPs. Instead of buying a rover, the government should buy “Kilometers of Cargo Transport” or “Megawatts of Night-time Power” from commercial infrastructure nodes described in the Field Guide.
  • Lead Agency: NASA (Commercial Moon to Mars Program).

Action 2: Deploy the Lunar Rail Pilot Program

  • The Problem: The EO’s 2030 call for a permanent outpost cannot be sustained long term by slow, battery-limited rovers.
  • Implementation: Accelerate the Field Guide’s Lunar Rail concept to connect the 2028 landing site to the 2030 outpost location. This would create an industrial corridor that bundles multiple services, e.g. power, data, and transportation, to reduce the cost of individual missions. Such linear easements along railroads would serve as the logistical spine for moving massive cargo fostering economic development in accordance with the EO.
  • Lead Agency: DARPA (transitioning to Space Force/NASA).

Action 3: Codify the Lunar Board of Trade

  • The Problem: The EO seeks $50B in private investment, but investors need price certainty.
  • Implementation: Use the Field Guide’s framework to establish a Lunar Commodities Exchange. Define the “Lunar Standards” for oxygen and water purity. This allows private companies to “pre-sell” resources they will mine in the near future to finance their current operations.
  • Lead Agency: Department of Commerce (Office of Space Commerce).

Action 4: Integrate “Defense-by-Commerce” in Cislunar Space

  • The Problem: The EO calls for US superiority and threat detection in cislunar space.
  • Implementation: Equip the Field Guide’s Infrastructure Hubs with Space Situational Awareness (SSA) sensors. By hosting defense sensors on commercial power/comms nodes, the U.S. achieves the responsive and adaptive architecture required by the EO at a fraction of the cost of dedicated military satellites.
  • Lead Agency: U.S. Space Force.

Conclusion

The Commercial Lunar Economy Field Guide is a ready-made roadmap for implementation of the Whitehouse’s Executive Order on Ensuring American Space Superiority. By treating the Moon as an industrial zone the administration can meet the prescribed milestones through commercial leverage and ISRU rather than massive new government spending. Execution of the plan should focus on contractual reform—buying services from the infrastructure nodes as defined in the Field Guide. With power, comms and security systems in place, companies like Galactic Resource Utilization (GRU) Space can build hotels on the Moon starting in the early 2030s to house scientists, entrepreneurs and maybe even tourists as described in their white paper.

Artist rendering of GRU Space’s hotel on the Moon. Credit: GRU Space
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TESSARAE for orbital biolabs and more

Conceptual illustration of an orbital biolab constructed using TESSERAE architecture. Credit: Aurelia Institute

At last year’s International Conference on Environmental Systems (ICES), Aurelia Institute Vice President of Engineering Annika Rollock presented a paper on development of an orbital TESSERAE habitat to conduct biotechnology research. TESSERAE (Tessellated Electromagnetic Space Structures for the Exploration of Reconfigurable, Adaptive Environments) covered previously on SSP, was conceived and developed by Ariel Ekblaw, cofounder and CEO of Aurelia as part of her doctoral thesis at MIT. A TED Talk by Ekblaw from last April provides more detail on the concept with footage of prototypes demonstrated in space on the International Space Station (ISS).

The paper “Development of a Flight-Scale TESSERAE Habitat Concept for Biotechnology Research Outpost Applications” by Rollock, Max Pommier, William J. O’Hara, and Ekblaw, presents preliminary findings from a case study on the TESSERAE habitat which aims to bridge traditional space station architectures with future-oriented, adaptive designs. Legacy space habitats, such as the ISS, rely on monolithic hulls or cylindrical modules constrained by launch vehicle fairings, limiting scalability and geometric flexibility. TESSERAE offers a departure from these norms by using flat-packed, tile-based modules that self-assemble in orbit to form a truncated icosahedron. This structure, commonly known as a “buckyball” sharing the same shape as the carbon molecule buckminsterfullerene (C60) named after architect and inventor R. Buckminster Fuller due to its resemblance to his geodesic dome designs, will enable larger volumes and novel configurations when connected together.

The authors provide more detail on the concept referencing a trade study presented at ICES 2023 by the Aurelia Institute, which reviewed historical and contemporary space architecture to identify gaps and opportunities. They underscore the need for habitats that are both innovative and grounded in proven engineering principles. The paper serves as a “dynamic snapshot” of the ongoing TESSERAE case study as of spring 2024, inviting collaboration rather than presenting a finalized design. It envisions a platform based on TESSERAE as a commercial biotechnology research outpost in Low Earth Orbit (LEO), aligning with NASA’s Commercial LEO Destinations (CLD) goals and the burgeoning market for microgravity-enabled research. The paper highlights subsystem analyses for environmental control, thermal management, and power, alongside novel interior layouts informed by user research and terrestrial architecture best practices.

The authors make the case that self-assembling structures like TESSERAE could revolutionize human spaceflight by enabling adaptive environments that support diverse crews, including non-professional astronauts. This is particularly timely as the ISS nears decommissioning in 2031, necessitating new orbital platforms for critical research with increasing involvement by private industry..

The mission overview lays out one possible operational vision for the 2030s: a TESSERAE microgravity platform sustaining human life, scientific inquiry with a biotechnology focus, and ancillary activities in LEO. Designed for a crew of four—two biotechnologists and two career astronauts—it features biotechnology applications, capitalizing on microgravity’s unique properties for protein crystallization and biologic medicines production.

Protein crystal growth in space yields superior quality due to reduced sedimentation and convection, facilitating precise structural data for drug discovery. The paper references applications in treating among other maladies, muscular dystrophy, breast cancer, and periodontal disease, citing decades of ISS-based experiments by pharmaceutical firms. Similarly, biologic medicines—proteins, enzymes, nucleic acids, and antibodies derived from natural sources—benefit from low-gravity acceleration in discovery and preclinical testing. The global biologics market is projected to reach over $700 billion by 2030, underscoring the potential economic upside. Innovations like Redwire’s seed-based crystal manufacturing and Varda’s in-orbit ritonavir production (an HIV antiviral) have demonstrated feasibility, with microgravity enabling bulk-free returns via seeds or small samples.

The concept of operations (ConOps) details a 32-tile assembly (20 hexagons, 12 pentagons, each 2.26 m edge length, 0.46 m thick), launched in a dispenser stacked aboard a SpaceX Falcon 9 launch vehicle. After dispensing out of the payload bay, orbital self-assembly employs electro-permanent magnets for bonding at the tile edges, forming a 493 m³ pressurized volume post-clamping and gasketing. Outfitting prioritizes autonomy: critical systems integrate into the tiles, with secondary elements (e.g., storage, mobility aids) added via robotics or minimal EVAs. After full systems checkout post-assembly, operations include 1–6 month crewed expeditions, cargo resupplies, and uncrewed intervals.

Comparative occupancy analysis positions TESSERAE favorably: at 123 m³ per person, it rivals the ISS (168 m³ for six) and Tiangong (113 m³ for three) emphasizing permanent quarters and lab space for its four-person upper limit, ensuring psychological and functional adequacy. This aligns with NASA’s CLD objectives, fostering commercial viability while accommodating “visiting scientists” alongside professionals.

With respect to interior concepts and design principles, TESSERAE’s non-cylindrical, open-central geometry introduces unique interior challenges and opportunities, diverging from conventional axial modules. The paper explores layouts tailored for diverse crews, drawing on user interviews (astronauts, analogue astronauts, scientists) and literature like Sharma et al.’s Astronaut Ethnography Project and Häuplik-Meusburger’s activity-based approach. Five core design principles and “desirements” guide this strategy: a human-centered approach accounting for bodily navigation and psychosocial needs; contextual affordances leveraging microgravity (e.g., multi-axis movement in open volumes); sensory mediation via lighting, acoustics, and airflow for zoned activities; accessibility with ample, clutter-free stowage; and a balance of permanence (fixed volumes) with flexibility (reconfigurable elements like folding partitions).

These principles inform environmental mediations for biotechnology: labs require vibration isolation and containment for experiments, while communal spaces mitigate isolation via views and biophilic design elements. The paper discusses layouts prioritizing flow, orientation, and adaptability. One configuration features a central “node” for socialization and exercise, ringed by radial spokes: private quarters, labs, hygiene nodes, and utility closets embedded in the shell. This exploits the buckyball’s symmetry for efficient use of space, with tethers and handrails guiding microgravity transit. Labs allocate ~100 m³ total, segmented for crystallization (vibration-dampened gloveboxes) and biologics (flow benches, incubators), in accordance with preliminary user needs.

Diagram (Figure 5 from paper) depicting four internal layout options, with key space dividers and elevation maps depicting the arrangement of functional areas on each external tile. Credits: Annika E. Rollock et al. / Aurelia Institute
Exploded view (Figure 6 from paper) of the Lofted layout option for the TESSERAE habitat. Credits: Annika E. Rollock et al. / Aurelia Institute

Sensory design mitigates monotony: variable LED lighting simulates diurnal cycles, acoustic panels dampen noise, and materiality ( e.g., fabric panels) enhances tactility. Stowage integrates nets and modular racks, addressing chronic ISS issues. Flexibility allows crew reconfiguration via magnetic mounts, supporting mission evolution. Hygiene and galley zones emphasize efficiency, with water-efficient fixtures tied to the Environmental Control and Life Support System (ECLSS). Overall, interiors blend spacecraft rigor with architectural humanism, fostering well-being for non-experts.

The authors provide a subsystem analysis discussing trades for ECLSS, thermal control, and power. ECLSS recommendations draw from ISS heritage leveraging NASA’s Carbon Dioxide Removal and Oxygen Generation Assemblies but adapt to TESSERAE’s modularity: distributed nodes per each individual tile reduce single-point failures, with regenerative loops for water and air.

Thermal management addresses the buckyball’s high surface-area-to-volume ratio, prone to radiative losses. Multi-layer insulation and variable-emittance coatings are proposed, integrated into tiles for passive control, supplemented by active radiators and heat exchangers. Finite element modeling was used to inform stress distribution across the tile seams.

Power generation leverages roll-out solar arrays deployed post-assembly, sized for 20–30 kW demands for the needs of the labs, ECLSS and other power systems. Trades evaluate photovoltaics vs. emerging tech, prioritizing launch mass. Batteries buffer eclipse periods, with guidance navigation integrated with attitude control via control gyroscopes, minimizing propellant use.

These analyses emphasize scalability: TESSERAE’s tiles enable redundant, upgradable subsystems, contrasting with legacy monolithic designs.

The paper identifies a few challenges. For instance, assembly reliability (magnet actuation in vacuum), pressurization integrity at seams, and outfitting logistics. But opportunities abound in biotech such as enabling “fly-your-own-experiment” for scientists, accelerating drug pipelines, and demonstrating adaptive habitats for lunar/Mars precursors. User research highlights psychosocial needs—privacy amid openness, sensory variety against confinement—which will inform iterative designs.

Future work matures hardware testing in microgravity (e.g., parabolic flights), refines trades via modeling, and pursues partnerships for CLD certification. The authors invite input, positioning TESSERAE as a collaborative pivot toward reconfigurable space living.

This case study encapsulates one of TESSERAE’s promises: a self-assembling, biotech-focused habitat merging innovation with pragmatism. By the 2030s, it could sustain crews in 493 m³ of adaptive volume in LEO, tapping into a $700B+ market while advancing human-centered space architecture. Preliminary insights from this work — from ConOps to design of interiors— lay the groundwork for transformative outposts that not only return benefits to human lives on Earth, but are preparing humanity to become a spacefaring species.

While the Aurelia Institute is a nonprofit organization, Ariel Ekblaw cofounded a startup called Rendezvous Robotics which aims to generate revenue building large-scale structures like antenna apertures, space solar power arrays and orbital data centers, all autonomously fabricated in space using TESSARAE. Rendezvous Robotics recently partnered with another startup called Starcloud which plans to fabricate gigawatt-scale orbital AI data centers using Ekblaw’s invention, a potentially huge new market forecasted to be just over the horizon by several tech leaders in the news recently. Blue Origin CEO Jeff Bezos just announced he’ll be leading a new AI company called Project Prometheus and says AI orbital data centers are coming in the next decade or two. Last May former Google chief executive Eric Schmidt acquired Relativity Space to put data centers in orbit. Earlier this month Elon Musk says in not more than 5 years, the lowest cost way to do AI compute, will be in space. And Mach33 Research, an investment research firm focused on the industrialization of space, predicts that orbital compute energy will be cheaper than on Earth by 2030. TESSARAE could be leveraged to assemble these space-based hyperscalers autonomously and quickly while proving out this reconfigurable technology which can be used to build large-scale adaptable habitats and other infrastructure in space for a multitude of applications. As stated on the their website,

“Aurelia is working toward geodesic dome habitats, microgravity concert halls, space cathedrals—the next generation of space architecture that will delight, inspire, and protect humanity for our future in the near, and far, reaches of space.”

Artist illustration of a habitat constructed from TESSARAE modules in Earth orbit. Credit: Aurelia Institute

Finally, in celebration of the 50th anniversary of the 1975 NASA Space Settlements: A Design Study, the Institute announced today they are sponsoring The Aurelia Institute Prize in Design for Space Urbanism. An award of up to $20,000 will granted for concepts of a functioning space station in one of three categories: A space station in LEO or at a Lagrange point; a space habitat in lunar orbit or on the surface of the Moon; or an automated industrial facility (e.g. focused on space mining, energy, biotech, etc.) in one of those locations.

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Novel design of a Mars Cycler

Above – Mars Cycler exploded section. Below – Cruise ship-sized Mars Cycler booster (left) and docking configuration (right). Credits: Offworld Industries Corp.

At the 54th International Conference on Environmental Systems held in Prague, Czechia, this past July, a paper was presented describing an innovative design of a large-scale Mars Cycler. The authors, A. Scott Howe, John Blincow, Theodore W. Hall, and Colin Leonard, make the assumption that a significant planetary migration to Mars will happen in the near future, citing Elon Musk’s often stated goal of establishing a one-million person colony on the Red Planet by 2050. The authors argue that Starship will not be a suitable transportation method for a large, non-professional clientele on what has historically been a six-month journey due to the physiological and psychological health risks of a long-duration mission (not withstanding a recent paper penned by University of Santa Barbara physics undergrad Jack Kingdon proposing two trajectories that reduce transit times to between 90 to 104 days each way).

Instead, they envision a “cruise ship” approach using a large, robotically constructed Mars Cycler that would continuously travel between Earth and Mars. The concept for a Mars Cycler was first conceived by Buzz Aldrin in a 1985 paper, and in recognition of his invention, is often referred to as an Aldrin cycler. This particular cycler design is advantageous because it would use minimal propellant to maintain its trajectory. The concept features a dual-torus structure, with a non-rotating outer torus for docking and a rotating inner torus to provide artificial gravity. The paper lays out in detail the specifications for a minimal-sized version with crew capacity of 52-61 people, and calculates the mass and equipment required for the vessel. The authors estimate that it would take 63 Starship launches (version 3) to deliver the construction materials and propellant to low Earth orbit (LEO). A scaled up larger cruise ship-sized version with a capacity of 1000 occupants would take 428 Starship version 3 launches, which is within the range of engineering possibility and certainly within the launch rate of thousands of Starships Elon Musk envisions as part of his Mars colonization plans.

The Mars Cycler would be assembled using Offworld Industries Corporation’s Sargon System, a family of new construction machines the company claims could build an entire space station in half a year (Blincow is CEO of Offworld Industries Corp). The novel construction technology autonomously assembles preformed hull panels loaded in a magazine, robotically dispensed, formed and welded into large toroidal (or other shaped) space stations ready to be pressurized.

The paper advocates for the cycler to provide artificial gravity to mitigate the deleterious health impacts of microgravity allowing occupants to maintain healthy muscle and bone density throughout the journey. The proposed design decouples an inner artificial gravity centrifuge from an outer non-rotating torus, which offers several operational benefits:

  • Distributed docking ports: The non-rotating outer torus can accommodate multiple visiting vehicles docking at various points around its perimeter.
  • Fixed systems: Solar panels and radiators can be mounted without the need for gimbals or motorized mounts, simplifying the design.
  • Seamless transfer: Crew and cargo can be transferred between visiting vehicles and the cycler without the need for spin-up or spin-down procedures.

The paper identifies several challenges to overcome in order to realize an operational Mars Cycler. The top five include:

  1. Large-scale space construction: The project requires the construction of very large orbital structures. A key challenge is maintaining tolerance control during assembly, ensuring panels fit together precisely and the torus closes properly.
  2. Attitude control and maneuvering: The paper assumes, but does not detail, that maneuvering large quarter-toroids in proximity to each other will be possible without “exotic solutions’. This is a significant challenge because each section would have its own center of mass and orbit, creating strain on connected elements.
  3. Artificial gravity implementation: A number of difficulties are discussed, including economic spin-up/spin-down, docking procedures while the structure is spinning, and performing extra-vehicular activities (EVAs) under rotation. The paper also notes that transferring power, control, information, and liquids between the rotating and non-rotating segments would be challenging.
  4. Mars surface infrastructure: The paper acknowledges that a major challenge is the “big elephant in the room of Mars surface infrastructure”. The entire concept is based on the assumption that the necessary infrastructure, such as propellant production facilities, will be in place on Mars by the time the cycler is ready.
  5. Life Support Systems: Sustaining human crews on a cycler for extended periods (e.g., months-long transits) requires robust life support systems for air, water, food, and waste management. The paper underscores the challenge of maintaining these systems with minimal resupply over multiple cycles.

Assuming these challenges could be solved, this interplanetary cruise ship design of a Mars Cycler is a new approach to deep-space travel, elegant in its simplicity. It offers a potential solution to the challenges of long-duration missions by providing artificial gravity via a rotating inner torus to ensure the health and well-being of future Mars colonists.

In addition to these cyclers providing a mode of safe space transportation, such large artificial gravity space stations could be permanently located in orbit around planets or moons that have surface communities in split life cycle space settlements which SSP covered recently. Such a facility could have duel use as an Earth-normal gravity crèche, providing birthing centers and early child development for families settling in the region. Colonists could choose to split their lives between rearing their young in healthy normal gravity settings until their offspring are young adults, then moving down to live out their lives in lower gravity surface settlements – or they may choose to live permanently in free space.

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AI networks for space settlements

Artist rendering of a robotic space farm on Mars controlled by a computer network utilizing artificial intelligence. Credits: Bryan Versteeg / Spacehabs.com

In an article in the National Space Society Space Settlement Journal, Bryce Meyer examines the integration of Artificial Intelligence (AI) into computer networks for space settlements. Meyer, an aerospace engineer, computer scientist and biologist is the founder and CEO of Cyan React, LLC, a startup that designs compact photobioreactors and provides expertise in space agriculture and life support for space habitats.

The paper describes the critical role of AI networks will play in enabling sustainable space settlements whether they be on the Moon, Mars, or in free space. These colonies, envisioned to minimize Earth resupply and achieve self-sustaining commercial operations, will face challenges due to limited human occupants (often under 100) and the absence of specialized expertise. AI systems can provide a solution that will bridge knowledge gaps, manage complex operations, and ensure rapid responses to critical issues, such as life support failures, where human reaction times may be insufficient.

The article categorizes AI into distinct families suited for space applications. Neural networks, good at pattern recognition, could help identify equipment anomalies. Generative AI (GAI), excellent at diagnostics and creative problem-solving, could propose solutions for crop failures in space farms or other equipment failures. Regression models would be leveraged for predictive analytics like forecasting resource needs.

These AI systems require robust integration with settlement infrastructure, using standard protocols like TCP/IP for communication. Training of AI agents involves learning from a pre-settlement knowledge base, periodic updates from Earth, and real-time inputs from sensors monitoring environmental conditions, equipment, and biological systems. Error management will be managed with AI outputs cross-checked by other AIs, rule-based systems, or human oversight to prevent cascading failures in critical systems.

Network architectures are key, with Local Area Networks (LANs) enabling low-latency, high-speed communication for real-time tasks like alarms and life support, while Wide Area Networks (WANs) connect settlements to external systems, such as orbital infrastructure or Earth-based servers . AI placement is strategic, positioned near action points within habitats (e.g., farms, life support systems) to minimize latency and ensure reliability in harsh extraterrestrial environments. Power constraints and radiation hardening are critical considerations for AI hardware.

The article presents a detailed scenario illustrating AI coordination in a mass flow system, as would be required in space farm. For example, crop wilting is detected by sensors, triggering a cascade of AI-driven actions: neural networks diagnose the issue, GAI suggests solutions (e.g., adjusting nutrient levels), and regression models predict outcomes. Human settlers, guided by augmented reality interfaces, validate and implement solutions, ensuring effective collaboration. The scenario underscores the need for AI to operate at multiple scales—individual plants, farm systems, and settlement-wide networks.

Bryce agreed to be interviewed via email on this enabling technology for space settlement. I am very grateful for him taking the time to dive deeper into the topic and for his detailed responses to my questions. Here is our discussion:

SSP: You mentioned that many of these AI systems are already in use in indoor farms and factories. Can you provide some examples of these instances?

BM…Not trying to pump a particular company but here are common examples:
Siemens is one of many companies that make networks of these AI enabled control systems, with control center software now: Siemens Industrial Copilot and SmartTron as well as AIRLOCK(InterLock) Systems.

Water Control: Evonik

There are also many new entry startups in this area, such as AGEYE (see below), and others, many have already tried and failed as businesses. Emerson Process is similar, with many offerings and architectures in Chemical Process Automation and Response. BASF is another with it’s xarvio® Digital Farming Solutions. Monnit makes Internet of Things (IoT) plant sensors and sensor reporting software.

It is a very active business area bridging strict rules based to AI enabled rules based and GAI systems with IoT.

SSP: In your example of an AI farm agent detecting a wilting problem with a tomato plant and coming up with a solution, you acknowledged that there are many ways in which ecosystem failures could a occur in a space farm and these scenarios would have to be anticipated to train the AI systems. Has work already been started on an AI controlled farm fault tree analysis, perhaps by the entities running the indoor farms you mentioned in Item 1?

BM…Absolutely! IoT and AI are used in combination in many indoor farms now, just not all the way to the point as shown in the paper, including the ‘recreational plant’ market and for food plants.  This is in active work now by many companies, AGEYE is one company that does have integrated solutions like the farm part of the paper (or very close to it). With a little development, automated control will combine the systems in #1, with the farm systems, with more advanced and trained systems, IoT sensors and controllers, to get to the settlement level.  It will take a merger of these to get there, but we are very close. Have parts, just need to integrate to get to the vision in the paper.

SSP: Prior to implementation for safe use in a space colony, AI systems would have to be trained on a variety of settlement functions in ground-based analogs. Perdue University’s Resilient ExtraTerrestrial Habitats Institute is doing work in this area as well as the Space Analog for the Moon and Mars at the Biosphere 2 facility in Arizona, and of course MELISSA in the EU. Are you aware of any other teams in academia or government working on this now?

BM…Really miss Ray Wheeler’s et al. NASA Biomass Production Chamber, which was the right size and type, would just need updates.

South Pole research station would work well for testing these systems…in a harsh place, limited human presence.

I know Space Development Network is proposing an inflatable farm to develop this technology too, though it needs funding.

AI control for factories and indoor farming is an active corporate area and they have their own extensive facilities, including near my home in St. Louis with Bayer (formerly Monsanto), though they aren’t focused on the particulars of space, per se, yet.

China also has extensive analog labs, since they do seek to beat the USA to long term Moon and Mars settlement. They occasionally publish.

Many colleges have funded work on vertical and indoor farming, several in my home state including at [University of Missouri-St. Louis] UMSL’s planned Yield Lab.  Technical Schools like Ranken also teach and develop methods for indoor farming that could help development of these AIs. All of these facilities can be used to shake out AI systems too.

SSP: In private industry, a few companies are actively involved in developing space-based agriculture. I’ve covered one such company, Orbital Farms, which leverages Earth’s “Dark Ecosystem”, the food chain based on bacteria that are chemotrophic, i.e. deriving their energy from chemical reactions rather than photosynthesis. An example of these type of organisms are bacteria that live near volcanic sulfur vents at the bottom of the ocean. The energy inputs and material flows of these ecosystems are 100 times more efficient in water and energy use per unit volume when compared to conventional photosynthetic food production. The very same organisms can be engineered to make pharmaceuticals, plastics, and a variety of other useful complex organic compounds. Have you considered this approach to optimize mass flows and utility in space farm ecosystems?

BM…Of course. I have considered bioreactors, both photobioreactors and non-light based systems, for a decade. They are the Swiss Army Knife of mass balancing, though I don’t see them as primary food source except in emergencies unless 3d printing and other methods become far better in the culinary sense. Food is critical for psychology too. As is the need to see green and feel and smell plants and crops. Bioreactors have many profiles and uses on Earth now, and the dark cycle chemosynthetic systems are among these. I don’t see a lack of electrical power a problem, just my 2 cents, due to nuclear reactors or space solar power in long term settlements, so I see gardens and farms. Carbon is the problem in a mass cycle. However, the dark cycle systems would be essential for making biochemicals that are either lacking from farms and algae or needed to control the mass cycling in systems. Since we are minus the huge soil ecosystem on Earth for a long while, and may need time sensitive production, the dark cycle systems would be a must just to control the overall system. I do see those on spacecraft that have limited volume, that provide bulk calorie cycling, along with smaller plant systems.

SSP: In your example in Figure 12 of a small settlement of 10 people where the mass flows are 22kg per day to and from the farm, how big is the farm in cubic meters and what would be grown there to provide enough sustenance and oxygen for the occupants?

BM…Around 1400 square meters, 2400 cubic meters (very pessimistically) assuming a VERY diverse crop mix including a few shrimp, multiple veggies and crops like potatoes or peanuts/soy, and bioreactor array with tanks, and walking areas, with continuous crop production ad infinitem. Sounds big, but that is about the size of two three-story healthy midwestern suburban houses, very roughly. Less diverse crop sets can shrink the farm drastically, to around 25% of the size, but with less dietary diversity.

SSP: With respect to training AI systems to be “space rated”, the first iterations to be implemented off Earth will not be entirely autonomous (as you have shown in your examples) and will have humans in the loop until error rates can be reduced to some tolerable level. With the speed at which AI and robotics are progressing today, while at the same time, settlement of the Moon and Mars seems to be advancing at a snail’s pace, do you see the two technologies converging in the near future so that when permanent colonies are finally established, AI networks will be able to autonomously control most critical functions without human intervention?

BM…I never will fully trust AI for everything, and I don’t think the settlers will either, at a minimum due to cybersecurity. That said, the advances in both systems and software will continue to allow more complex settlements monitored by fewer people. Automation will really will be a core technology in expanding settlements, and starting them. Farms could be growing and operating steady state before the first long term residents arrive, and as a settlement expands, it could add modules and let AI get it started and growing before bolting it onto a smaller settlement. Some things will see robotics as repair agents. The AI technology expansion will allow for more long term optimization as well, and continue to add resiliency to the settlement.

You could see a retirement home or factory on the moon with only a few human workers to keep the settlement running, a few medical technicians that are AI assisted, and robots that fix many things without bothering the staff.

SSP: You have suggested in a previous post on SSP that space farms on Mars could be the bread basket for the outer solar system. Another space farm advocate, retired software engineer Marshall Martin, has proposed a roadmap for their implementation starting with ground based analogs, but progressing mainly to rotating free space settlements, eventually resulting in millions of farms feeding billions of people throughout the solar system. When do you think we’ll see the first prototype closed loop farm implemented in space?

BM…I want farms everywhere, grounded and floating [in free space], because I want to see Trillions of Happy, Smiling Babies everywhere.

I would bet either Artemis, a company, or China fields one in the next 35 years for sure, likely sooner, just to prove the concept. Orbital factories could drive the need as much as a lunar base, just to limit resupply, but a Mars base or space station that is beyond cis lunar space will have to have such a close[d] cycle farm as a must due to limited resupply. So, when depends on if the cost to orbit gets very cheap, and cost to [the] Moon gets cheap. Cheap lift in cislunar space would limit the need to fully recycle, but beyond that distance the case gets much stronger. If it stays expensive to [get to] the Moon, the Moon would drive the need, and the farm gets built sooner.

In his conclusion to the article Meyer holds that AI complexity must align with settlement needs, balancing sophistication with reliability. Interdisciplinary collaboration is essential to refine these systems through scenario-based testing and practical implementation. By empowering minimally trained settlers, AI networks enhance sustainability, safety, and mission success, laying a foundation for long-term human presence in space.

Meyer has his own website where he collates his research and links about closed cycle farming and other space ecology topics. He is also a NSS Space Ambassador.

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Perspectives on Mars terraforming research

AI generated image of Mars in the process of being terraformed. Credit: Gemini

The concept of terraforming Mars was first proposed by John B. S. Haldane in his 1927 essay “On Being the Right Size”, where he touches on the idea of altering planetary environments to make them habitable for humans, including Mars. However, the term “terraforming” itself was coined later by science fiction author Jack Williamson in his 1942 story “Collision Orbit”, where he described transforming alien worlds into Earth-like environments. Haldane’s speculative mention in 1927 is generally considered the earliest recorded proposal of the concept applied to Mars, though it was not detailed or Mars-specific. More technical discussions of Mars terraforming emerged in the mid-20th century with advancements in space science.

Carl Sagan discussed terraforming Mars in his scientific work and popular writings. In a 1971 paper, “The Long Winter Model of Martian Biology: A Speculation”, published in Icarus, Sagan explored the idea of making Mars habitable by using dark-colored plants or microorganisms to reduce the planet’s albedo, leading to better absorption of sunlight to warm the surface, which would release water and carbon dioxide from the polar caps and regolith. This would thicken the atmosphere and create conditions suitable for life. His ideas influenced later science fiction, including Kim Stanley Robinson’s magnus opus Mars trilogy, and remain a foundation for modern terraforming discussions.

The research up until now indicate that it is a complex, long-term project, taking hundreds of years and could be controversial due to ethical challenges. In an article in Nature Astronomy, a fresh look using innovative terraforming methods is presented which could accelerate the warming of Mars by at least 30°C within a few decades, although complete habitability for human flourishing would likely take at least a century. The paper emphasizes the need for scientific research to understand if and how this could be done. Ethical concerns are also addressed with care in the paper.

The article suggests that terraforming Mars should progress in three phases: first, warming the planet; then, introducing hardy organisms to start an ecosystem; and finally, engineering a biosphere with enough oxygen to support human life. The technology proposed to facilitate warming of the planet in the first phase includes orbiting solar sails, silica aerogels, nanocellulose, and engineered aerosols.

Large, lightweight reflective solar sails deployed in space would act as mirrors to reflect solar radiation on to the Martian surface, increasing the amount of heat the planet absorbs. The paper notes that the current insolation of Mars is ~130 W/m², with net absorbed energy at ~125 W/m², resulting in an average surface temperature of about -63°C. By redirecting additional sunlight, reflectors in orbit could significantly boost this energy input which would raise the surface temperature.

Ultra-light, porous silica aerogels with excellent insulating properties could be deployed in transparent or translucent blankets over Martian ice deposits, particularly in polar or high-latitude regions with abundant frozen water reserves. Aerogels trap heat by allowing sunlight to penetrate while preventing infrared radiation from escaping, creating a localized greenhouse effect. This would warm the underlying ice, potentially melting it without requiring global atmospheric changes. The paper emphasizes the aerogel’s biocompatibility, ensuring they would not harm the existence of a potential Martian ecosystem.

Nanocellulose is a lightweight, strong, and renewable nanomaterial derived from cellulose, It could be spread over the Martian surface acting as a thermal blanket similar to aerogels, or as a component in structures that trap heat. The paper suggests it could be tailored to maximize solar absorption in the visible spectrum while reflecting infrared to retain heat, contributing to localized or regional warming. Nanocellulose could support targeted warming, potentially complementing aerogels in creating habitable microenvironments. Its lightweight nature makes it practical for transport and deployment, aligning with the paper’s focus on mass-effective solutions.

Engineered aerosols are fine particles designed to be released into Mars’ thin atmosphere to enhance its greenhouse effect. Unlike older fluorocarbon proposals, which were less efficient and environmentally risky, these aerosols are optimized for biocompatibility and ease of control. These aerosols absorb and scatter solar radiation, trapping heat in the atmosphere. They can be tailored to target specific wavelengths, maximizing heat retention while minimizing harmful effects on potential biology. The paper notes that Mars’ low heat capacity allows these aerosols to warm the planet faster than on Earth, potentially achieving a 30°C increase within a century. By thickening the atmosphere’s greenhouse layer, aerosols could raise global or regional temperatures, facilitating the melting of ice and the release of water vapor, which further enhances warming because water vapor itself is a greenhouse gas.

Another option to facilitate atmospheric warming, proposed in a paper in Scientific Advances last year, would be to engineer and mass produce “nanorods” from Martian regolith tuned to strongly absorb infrared radiation, thereby supercharging a greenhouse effect.

Figure 3 from paper on a nanoparticle warming method for Mars terraforming efforts. Credits: Aaron M. Geller, Northwestern, Center for Interdisciplinary Exploration and Research in Astrophysics via Scientific Advances

Mid-term, anaerobic organisms tolerant to Mars’ harsh conditions could be introduced, initiating ecological succession and producing oxygen. The lead author on the Nature Astronomy paper is Erika Alden DeBenedictis, CEO of the San Francisco based nonprofit Pioneer Labs, who’s mission is to engineer microbes that can thrive in extreme environments. As stated on the website, “These new pioneer species can pave the way to greener planets by remediating soil, upcycling waste streams, and making harsh areas more friendly to life.”

SSP has covered a similar approach to terraforming the Red Planet with introduction of pioneer species such as the desert moss Syntrichia caninervis, an organism that can survive the frigid temperatures, low ambient pressure and harsh radiation on Mars while helping to boost oxygen levels and fostering soil fertility.

This middle phase would be ideal for para-terraforming, a more limited approach to making localized regions of Mars habitable, prior to fully terraforming the entire planet. It involves creating enclosed, controlled environments—such as domed habitats or sealed craters—where temperature, atmosphere, and other conditions are artificially maintained to support human life or simple ecosystems. Kent Nebergall, chairman of the Mars Society Steering Committee, has proposed this approach by building an enclosure over Hebes Chasma, a canyon the size of Lake Erie just north of Valles Marineris.

Top: Artist concept of kilometer scale arches built above space settlements and enclosing a Martian canyon to provide a para-terraformed environment.  Bottom: Magnificent view from below depicting these domes at cloud level on a typical summer day. Credits: Kent Nebergall / Aarya Singh

The Space Development Network has also advocated for this approach.

The paper suggests terraforming in this middle phase could support upwards of 10,000 people per site with automated farming, while the end goals are constrained by physical, chemical, and biological limits, perhaps necessitating a multicentury timeline. This phased approach highlights the gradual, research-driven nature of the project, acknowledging the long timescales involved.

The final phase involves establishing a sustainable, oxygen-rich ecosystem capable of supporting advanced plant life and, eventually, the ability to support human settlements without life support systems. Atmospheric oxygen would be increased to at least 0.1 bar to enable humans to breathe without pressure suits. This would be achieved through the widespread propagation of photosynthetic organisms like engineered plants or cyanobacteria. The paper notes that this slow oxygen build-up, potentially taking over a century, requires sustained energy inputs, possibly from multi-terawatt power sources or solar concentrators, to accelerate the process. The project would need ongoing climate engineering to maintain temperature and pressure, such as controlled greenhouse gas releases. Because Mars does not have a magnetic field to deflect solar particle events and galactic cosmic rays, engineered solutions would be required to prevent loss of oxygen and to shield Martian settlers from radiation. Through deployment of large-scale electromagnetic coils or magnetic shields in orbit or on the surface, a localized or planetary magnetic field could be created, mimicking Earth’s magnetosphere. This concept has been proposed by Dr. James Green, former chief scientist at NASA who retired from that role in 2022.

With respect to ethical concerns, there is considerable debate over preserving Mars as a pristine environment versus transforming it, with implications for potential Martian life that may exist there. The paper notes that human presence during exploration and/or settlement will introduce orders of magnitude more Earth microbes (then those that may have been present on probes that have already landed there), necessitating a search for extant Martian life through sample returns and deep aquifer exploration prior to initiation of terraforming efforts. The authors suggest that terraforming technologies could benefit Earth, such as developing desiccation-resistant crops, but emphasize the need for science-informed engagement with stakeholders. The long timescale for terraforming is noted as a constraint for politics and science, highlighting the need for long-term planning and international cooperation.

There are more audacious proposals such as Robert Zubrin and Chris McKay’s plan for terraforming Mars in 50 years. Zubrin, a prominent advocate for Mars exploration and terraforming, argues that there is no extant life on Mars, thus alleviating ethical concerns about altering the planet’s environment soon. In his view put forward in his book The Case for Mars, extensive scientific investigations analyzing data from Mars rovers and orbiters, have found no conclusive evidence of current microbial or other life forms, suggesting Mars is a barren world. He contends that the absence of indigenous life eliminates moral objections to terraforming, as there are no ecosystems to disrupt or native species to harm. Zubrin emphasizes that terraforming Mars into a habitable environment for humans, would foster scientific advancement and human expansion without ethical conflicts, provided ongoing searches for life—such as soil sample returns—continue to yield negative results. This position is echoed in the paper which notes the need to confirm the absence of life through further exploration but supports initiating terraforming research given the evidence to date.

As Mars terraforming efforts advance, the viability of the planet as a sustainable environment for surface settlements may progress according to the Pancosmorio Theory which posits that ecosystems necessary to sustain life gradually acquire sufficient area and availability of resources (e.g. sources of energy) as their circular economies evolve toward closure such that dependency on supply chains from Earth begins to diminish.

The paper makes a compelling case for prioritizing Mars terraforming research, aligning with current exploration priorities while informing future decisions about an eventual human presence on Mars. The authors acknowledge the complexity, controversy, and long-term nature of the project, advocating for a science-driven approach to address feasibility, ethics, and potential benefits for both Mars and Earth.

Dr. DeBenedictis will be discussing these topics in a plenary talk titled “Opportunities for a Green Human Civilization on Mars” at the Mars Society Convention next month.

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Pale Red Dots on Mars

Conceptual illustration of two Pale Red Dot villages on Mars serviced by SpaceX Starships. Credits: Pale Red Dot Team*

Pale Red Dot is an acronym for Polis-based Architecture for the Long-term Exploration of the Red planet, with Exciting and Diverse Developmental Opportunities to Thrive. This concept, which was the first place winner of the NASA 2023 RASC-AL competition in the category of Homesteading Mars by a team* at the Massachusetts Institute of Technology Space Resources Workshop, focuses on establishing a city-state with Earth-independence supporting extensive scientific exploration on Mars. NASA’s RASC-AL (Revolutionary Aerospace Systems Concepts – Academic Linkages) competitions foster innovation of aerospace systems concepts, analogs, and technology by bridging gaps through university engagement.

This architecture envisions sending robotic precursor missions to Mars following experience gained from NASA’s Artemis program to survey sites, test technologies, and stockpile resources like water and propellant. Lets be honest up front that this paper is two years old and timelines for return to the Moon have been moved out. Predictions on milestones in the paper for this plan as described below should take these delays into account. With the current Trump administration the fate of Artemis program is evolving. There are many possibilities being proposed to streamline NASA’s plans, one of which by retired aerospace engineer and entrepreneur Rand Simberg, leverages public-private partnerships to get humans back to the moon. Keeping this in mind, when humans return to the lunar surface, Pale Red Dot would leverage the engineering knowledge gained from robotic landers and human missions used in Artemis or any subsequent initiative that emerges.

Next, in 2035 (at the earliest), robotic cargo SpaceX Starships would deliver approximately 5,800 tons of equipment consisting of habitats, nuclear microreactors, farming modules, manufacturing facilities, and in-situ resource utilization (ISRU) systems. By 2040, two crewed Starships would transport 36 colonists to Mars to establish two closely located villages. Costs would be shared by nations that are signatories of the Artemis Accords, 56 and counting as of this post.

The study used a modelling approach that prioritized safety and crew health in design of the architectures, both in transportation and surface facilities. Relying heavily on NASA’s current career permissible limits for space radiation, exposure was minimized by splitting the crew among two Starships, each one adding a 71-ton 35cm polyethylene shield, and dashing to Mars within 113 days. Upon arrival, to guard against galactic cosmic radiation and solar particle events, the initial surface habitats will have integrated 3m water tanks in their roofs for radiation shielding. The plans call for gradually building out radiation-proof underground tunnel habitats. Although not considered in this scenario, locating the settlements in a lava tube could be advantageous not only for ready-made radiation protection but thermal management as well.

The Pale Red Dot (PBD) architecture emphasizes robustness and thriving, rather than just survival, through substantial infrastructure supporting 36 crew members across two Martian villages. This includes extensive makerspaces and significant reliance on ISRU. The two nearby villages are designed to be energy-rich, water-rich, food-rich, time-rich, and capability-rich, with substantial self-rescue capabilities.

Diagram from Figure 4 in the paper depicting one of two villages of the Pale Red Dot architecture showing zone layout with modules for farms, habitation, mission utilization and makerspaces. Credits: Pale Red Dot Team*

The site chosen for the PRD settlements was based on a NASA Exploration Zone workshop in 2015. Called Deuteronilus Mensae, its situated near a glacier water source, in a hilly region that may be suitable for tunneling. More recent discoveries by the European Space Agency’s Mars Express orbiter, using its MARSIS radar, have revealed extensive water ice deposits up to 3.7 km thick beneath Mars’ equator in the Medusae Fossae Formation.

Extraction methods for sourcing in situ water were not addressed in the PRD architecture. This should not be a problem though as the communities could leverage methods that have already been validated, such as the RedWater System which could drill for, and collect, subsurface water ice.

The paper argues that such a large architecture, with its economies of scale and specialization, is crucial for mitigating the risks associated with a long-duration, minimally resupplied mission to Mars. Crew time modeling suggests that smaller missions with 12 or fewer people would not provide sufficient free surface traverse time for meaningful science and exploration. The estimated lifecycle cost for this campaign is $81 billion, with a peak annual cost of $6.6 billion.

The PRD concept highlights the potential for creating a true community on Mars with sufficient social complexity for humans to thrive. Furthermore, it proposes the geopolitically significant option of including crew members from every Artemis Accords signatory in the first human mission to Mars. Comprehensive details are provided on the dual-habitat architecture, concept of operations, mission control, technology roadmap, and risk burn-down plan.

* MIT Pale Red Dot Team Membership:

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Resilient ExtraTerrestrial Habitats Institute at Purdue University releases its Impact Report

Artist impression of a lunar habitat designed for resiliency and autonomy. Credit: Resilient ExtraTerrestrial Habitats Institute

The Resilient ExtraTerrestrial Habitats Institute (RETHi) is at the forefront of developing autonomous and resilient habitats essential for space settlement. The NASA-funded organization just released its Impact Report summarizing work completed to date. SSP reported on RETHi back in 2020.

A key driver for RETHi’s imperative of autonomy in these habitats is the increasing communication delays and limited bandwidth that will severely restrict interaction with controllers on Earth as habitats are established further from home. These limitations necessitate new approaches for managing space habitats autonomously, fundamentally shifting the operational philosophy for future missions. Unlike near-Earth operations where Mission Control provides real-time oversight and intervention, the remote and harsh environment of deep space demands that habitats become self-sufficient entities. This means that intelligence, diagnostic capabilities, and decision-making must reside on-board, transforming the paradigm from remote control to local autonomy. This is a critical design constraint that permeates all of RETHi’s research, influencing everything from structural design to life support systems and robotics.

RETHi’s research is organized into three interrelated thrusts, each addressing a critical aspect of a comprehensive framework for self-managing systems:

  • Resilience (Architecture): This thrust focuses on the fundamental design of habitats. It involves choosing design features and tools to maximize resilience, assessing safety controls, and developing a resilience-based design procedure aligned with NASA’s processes. This ensures that resilience is embedded into the very fabric of the habitat from its inception, making it inherently robust.
  • Awareness (Detection + Diagnosis + Decisions): Addressing the need for autonomy in operations, this thrust aims to detect damage and disruptions, diagnose issues, and support decision-making autonomously. This represents a significant departure from traditional human space flight operations, which rely heavily on large Mission Control teams. The goal is to enable the habitat to “understand” its own state and the nature of any anomalies.
  • Robotics (Enable Action): This thrust is dedicated to expanding the capabilities of autonomous systems by increasing the scope of interventions that can be carried out automatically by robots. This is crucial for construction, maintenance, and repair in hazardous environments where human presence might be limited or too risky.

RETHi’s research is supported by three complementary testbeds, each serving a distinct but integrated purpose, forming an efficient iterative design and validation pipeline:

  • HabSim: This is a computational model of core space habitat subsystems. It incorporates damageable and repairable properties, sensors, and agents for anomaly detection and repair. HabSim can simulate various disruption scenarios, including micrometeorite impacts, fires, Moonquakes, and nuclear leakage. It primarily helps users learn to create and maintain resilient habitats by assessing decision strategies and resilience through simulation-based design, which can reduce mission costs and increase crew safety.
  • CDCM (Control-oriented Dynamic Computational Model): This capability provides a specialized language for rapid prototyping of machine-readable models that capture causal relationships in complex systems. This enables automatic diagnostic reasoners and uncertainty quantification, which are crucial for developing intelligent, self-diagnosing systems.
  • HARSH (Human-Centered Autonomous Resilient Space Habitats): This testbed is a cornerstone of RETHi’s research, providing a unique cyber-physical platform for validating the complex interplay of hardware and software in autonomous space habitat systems. As the physical validation layer, HARSH takes the insights, algorithms, and models developed and refined in HabSim and CDCM, and tests them in a hardware-in-the-loop environment to confirm their real-world efficacy.

These three complementary testbeds provide a sophisticated, multi-stage approach to research and development. HabSim allows for broad, rapid computational exploration of scenarios and design strategies, providing initial insights. CDCM provides the formal language and tools for precise diagnostic reasoning and model building. HARSH then serves as the high-fidelity, cyber-physical validation platform, where the most promising concepts from the computational realm are rigorously tested against physical realities. This iterative process—from broad simulation to precise modeling to hardware validation—minimizes risk, optimizes design, and accelerates the development cycle for a mature engineering pipeline of complex, safety-critical systems.

The RETHi Impact Report summarized the status of many of the Institute’s research initiatives. Although all are important, this post will highlight progress in two key areas of interest: The HARSH testbed and the design of a habitat’s Environmental Control and Life Support System (ECLSS).

Purpose and Unique Capabilities of HARSH

HARSH is a cyber-physical testbed designed to investigate advanced systems health management capabilities for complex systems with deep informational dependencies. The facility bridges the gap between digital simulation and physical reality, allowing for a more comprehensive understanding of system behavior.

The platform’s unique strength lies in its ability to trigger realistic disruption scenarios using hardware and test autonomous recovery. This capability distinguishes HARSH from purely computational models by enabling real-world interaction, sensor feedback, and the validation of autonomous responses against actual physical system behavior. While computational models like HabSim and CDCM are invaluable for initial design and rapid prototyping, HARSH serves as the crucial validation bridge from simulation to reality. It is where theoretical models and algorithms are put to the ultimate test against physical realities, including hardware limitations, sensor noise, latency, and real-world environmental interactions. This is an indispensable step for ensuring reliability and eventual flight certification of autonomous systems.

Facilitating Investigation of Advanced Systems Health Management

HARSH’s cyber-physical nature allows for the investigation of advanced systems health management capabilities, which are crucial for maintaining complex space habitats, especially those with deep informational dependencies. This entails a focus on integrated diagnostics, prognostics, and self-healing mechanisms across multiple interconnected subsystems. In a deep space habitat, a failure in one system, such as a power supply, can quickly cascade to others, like the ECLSS or communication networks.

The ability to test autonomous recovery under realistic hardware-induced disruptions is central to HARSH’s role in validating the Awareness (detection, diagnosis, decision) and Robotics (enable action) thrusts in a practical, integrated setting. To attain advanced systems health management capability, a focus that transcends simple fault detection is required. It implies a sophisticated ability to continuously monitor, diagnose, and predict the health of complex, interconnected systems. HARSH’s ability to test deep informational dependencies and autonomous recovery provides a proactive approach to resilience, where the system not only identifies a problem but also takes corrective action to prevent cascading failures and restore functionality, thereby minimizing the need for human intervention and ensuring mission continuity.

Advancing Life Support Systems for Deep Space: RETHi’s ECLSS Research

As we all know, the ECLSS is critical for sustaining human life in the hostile, closed environment of deep space settlements. The life support system provides essential functions such as breathable air revitalization, water recovery, waste management, and thermal control, directly impacting crew health and performance. The extended durations of deep space missions (and eventual evolution to permanent communities) necessitate a highly reliable and resilient ECLSS, capable of operating autonomously and recovering from disruptions without immediate help from Earth, given the significant communication delays and the unlikelihood of the success of rescue operations due to long transit times.

While a habitat’s structural integrity and autonomous systems are vital, the ECLSS provides the breathable air, potable water, and stable thermal environment necessary for human survival. Any significant failure in these systems directly jeopardizes the safety of the habitat’s occupants, making them the ultimate determinant of mission duration and crew survivability. Therefore, the resilience of an ECLSS will directly dictate how long a mission can last and whether the crew can survive unforeseen events, particularly when autonomous recovery is the only option.

Development of High-Fidelity, Physics-Based Simulation Models

RETHi has developed a high-fidelity, physics-based simulation model for an ECLSS, a sophisticated approach that accounts for the underlying physical principles governing the system’s behavior, allowing for a deep and accurate understanding of its performance.

This advanced model is specifically designed to predict interior conditions under nominal and disruptive scenarios. This capability is vital for understanding how the habitat’s internal environment responds to various stresses, from equipment failures to external impacts, and for evaluating the effectiveness of mitigation strategies. This method of modeling can predict interior conditions under nominal and disruptive scenarios, enabling a proactive, rather than reactive, approach to resilience. Instead of waiting for failures to occur and then responding, RETHi is developing tools to anticipate how the ECLSS will behave under various forms of stress. This predictive capability allows designers to identify vulnerabilities, optimize system responses, and develop robust contingency plans before a space habitat is established, significantly enhancing safety, reliability, and the potential for autonomous recovery. It moves beyond simple performance modeling to detailed stress-testing and failure mode analysis in a virtual environment.

Evaluation of ECLSS Resilience Under Nominal and Disruptive Scenarios

The ECLSS simulation model allows for the evaluation of system resilience. This means the model can assess the system’s ability to withstand disturbances, adapt to changing conditions, and recover from various challenges, ensuring continuous life support. By simulating disruptive scenarios, researchers can understand the precise impact of failures, optimize control strategies, and develop autonomous recovery protocols for critical life support functions, minimizing the need for human intervention during emergencies.

Evaluating system resilience under disruptive scenarios goes beyond merely ensuring individual ECLSS components are reliable. It validates that the system has the ability to maintain its critical functions even when components fail or external disturbances occur. This shifts the focus from preventing individual failures to ensuring the overall system can adapt and recover, which is a hallmark of true resilience in complex, high-stakes environments where human intervention may be limited. This holistic view is essential for long-duration deep space missions, where adaptability is paramount.

SSP covered similar research by Curt Holmer in his master degree thesis modelling the stability of an ECLSS back in 2021. That work attempted to capture the complex web of interactions between biological, physical and chemical processes and detecting early warning signs of critical transitions between systems so that appropriate mitigations can be taken before catastrophic failure occurs. RETHi’s approach takes stability modelling to a deeper level, enabling ECLSS designers to understand the complex interdependencies and vulnerabilities of the system to determine proactive countermeasures.

Conclusion: Paving the Way for Future Space Habitats

The Resilient ExtraTerrestrial Habitats Institute at Purdue University is playing an indispensable role in driving the design and development of resilient and autonomous habitats, which are critical for the future of space colonization. The institute’s integrated, multi-faceted approach to autonomous resilience, exemplified by the HARSH cyber-physical testbed and its pioneering ECLSS research, is foundational for achieving long-duration human presence off Earth.

RETHi’s strategic organization into resilience, awareness, and robotics initiatives address the complex challenges of human survival in deep space, where communication delays necessitate on-board intelligence and self-sufficiency. HARSH serves as the crucial validation bridge, transforming theoretical models and algorithms into tested, real-world solutions for autonomous recovery and systems health management. Concurrently, the high-fidelity ECLSS models ensure that the fundamental life support functions remain robust and adaptable under stress, directly impacting crew safety and settlement longevity.

The comprehensive nature of RETHi’s work positions it as a leader in future large-scale, interdisciplinary research initiatives for resilient space habitats. The Institute’s holistic understanding of the complex challenges of space colonization fosters integrated solutions across multiple scientific and engineering domains, supported by robust testing infrastructure. The Institute’s current research findings are a blueprint for effective advanced research and development needed for the next frontier of human expansion into the solar system, emphasizing a paradigm shift towards self-sufficient extraterrestrial settlements.

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Interlune attracts customers for Helium-3 mined from the Moon

Conceptual illustration of an excavator gathering lunar regolith, which upon separation and extraction of Helium-3, would transfer the valuable cargo to a spacecraft for shipment back to customers on Earth for industrial applications. Credits: Interlune

Payload reports that Seattle based Interlune, a space resources company, on May 7 inked a deal with its first customer Maybell Quantum to purchase thousands of liters of Helium-3 (He-3) sourced on the Moon. Interlune has developed an innovative excavator that will gather lunar regolith, process it and separate out He-3 for return to Earth. The company plans to launch a prototype of their equipment to the Moon in 2027, establish a pilot production plant by 2029, and deliver thousands of liters of He-3 to Maybell, a cutting edge quantum computing infrastructure company, for annual deliveries through 2035.

On the same day, Interlune entered in to a purchase agreement with the Department of Energy Isotope Program to deliver 3 liters of He-3 no later then 2029. The DOE IP utilizes He-3 primarily for scientific research, neutron detection, and cryogenic applications that support its mission to produce and distribute isotopes for research, medical, industrial, and national security purposes.

What’s the market for He-3? In 2023, the global He-3 market was valued at approximately USD 178.68 million, with projections to reach USD 224.59 million by 2031, growing at a compounded annual growth rate of 2.9% (2024–2031). Currently, He-3 has applications in medical imaging, neutron detection in border security, cryogenics and quantum computing; and of course aneutronic nuclear fusion research. This latter application has been touted for decades as a huge potential market for mining He-3 on the Moon as it is extremely scarce on Earth, with most supplies derived from tritium decay in nuclear weapon stockpiles, mainly in the U.S. and Russia. The going rate for Helium-3 is about $20M per kilogram.

Aneutronic fusion produces minimal neutrons as byproducts. This is advantageous because it reduces radioactive waste, simplifies reactor design, and allows for direct energy conversion (DEC). This method of generating power works by capturing the kinetic energy of the positively charged protons in the plasma, converting it directly into electricity using electromagnetic fields without the need for steam turbines. The most common He-3 fusion reaction is deuterium-Helium-3 (D-He-3), where deuterium (D, a hydrogen isotope) fuses with He-3 to produce a Helium-4 nucleus and a high-energy proton, releasing approximately 18.4 MeV of energy.

The current front runner using this approach is Everett Washington startup Helion Energy targeting commercial power generation by 2028. Their modular generators (roughly the size of a shipping container) are designed to power data centers or industrial facilities at a projected cost of ~1 cent per kWh. Helion signed a Power Purchase Agreement with Microsoft in May 2023 to deliver at least 50 MW of fusion power by 2028. They are also collaborating with Nucor, a North American steel products company, to build a fusion power plant on one of its steel mill sites in the United States.

Helion uses a pulsed non-ignition magneto-inertial fusion system called a Field-Reversed Configuration (FRC). Two FRC plasmoids (doughnut-shaped quasi-stable plasma structures) containing D-He-3 fuel are accelerated toward each other at over 1 million mph using magnetic fields, collide, and are compressed to fusion conditions (>100 million °C). Energy is extracted inductively as the plasma expands via DEC.

Achieving and maintaining 100 million °C will be extremely challenging. Some experts doubt Helion’s 2028 timeline, citing the difficulty of achieving net energy gain (Helion has not yet achieved engineering breakeven). This is why Interlune is focusing on more near term markets such as Maybell’s dilution refrigerators to provide cryogenic cooling for quantum computing customers.

Image of Maybell Big Fridge, a dilution refrigerator that utilizes He-3 to provide cryogenic cooling below 10 millikelvins for quantum computers. Credits: Maybell Quantum

Executing Interlune’s business plan will be difficult as all components in the supply chain provided by commercial partners need to work in concert like a well oiled machine. Launch vehicles will have to transport the excavators to lunar orbit and landers (still in development) need to deliver the equipment to the surface. After the He-3 is processed and stockpiled, a return craft will have to launch it back into space, return it to Earth, and reenter the atmosphere safely to deliver the cargo back home for distribution to customers.

On the bright side, if the company can secure a reliable supply chain for He-3 other potential customers with applications such as fusion propulsion for rapid transit throughout the solar system are gradually progressing toward technology readiness. Princeton Satellite Systems in New Jersey is close to developing a Direct Fusion Drive using their own FRC reactor design. The system is based on over 15 years of research at the Princeton Plasma Physics Laboratory (PPPL)

Conceptual illustration of a rocket utilizing fusion propulsion. Credits: Princeton Satellite Systems

According to the company’s website, once the support infrastructure is in place, “… Interlune will harvest other resources such as industrial metals, rare Earth elements, and water to support a long-term presence on the Moon and a robust in-space economy.”

Update July 10, 2025: Another company competing in this space, Scottsdale, AZ based Lunar Helium-3 Mining, LLC (LH3M) recently secured five patents for their end-to-end process for detection, extraction and refinement of He-3 sourced on the Moon.

Conceptual illustration of potential design of LH3M rovers harvesting He-3 from lunar regolith for refinement and transport back to customers on Earth. Credit: LH3M

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Sierra Space and payload integrator Tec-Masters to facilitate test of Honda’s Circulative Renewable Energy System on the ISS

Artist impression of Sierra Space’s Dream Chaser space plane Tenacity en route to the ISS. Credits: Sierra Space.

Honda is teaming up with Sierra Space and Tec-Masters to test their Circulative Renewable Energy System (CRES) designed to use water and sunlight to produce oxygen, hydrogen, and electricity for use on the Moon. The company’s research suggests that CRES could power a lunar colony, providing life support and fuel while recycling water in a closed-loop system from water sourced in situ.

Honda’s CRES is designed to support lunar activities by generating essential resources using sunlight and water extracted from lunar regolith or ice deposits, especially at the Moon’s polar regions. The system employs a high differential pressure water electrolysis process, which breaks down water into high-pressure hydrogen and oxygen. In a lunar colony, oxygen would be used for breathable air as well as stored in fuel cells to produce electricity, while the water byproduct is recycled back into the system, creating a closed-loop cycle. CRES is efficient, lightweight, and low-maintenance, ideal for settlements established in the harsh lunar environment, including extreme temperature fluctuations and low gravity. The system’s ability to operate under these conditions makes it suitable, potentially reducing reliance on Earth resupply and supporting a sustainable lunar presence.

Honda’s CRES is a sophisticated technology developed to support human activities on the Moon by leveraging local resources. It is part of a joint research effort with the Japan Aerospace Exploration Agency (JAXA), an international partner in NASA’s Artemis program, which seeks to establish a sustainable human presence on the Moon.

Circulative renewable energy system Honda is working to develop as part of the infrastructure for humanity’s sustained habitation on the Moon where resources other than sunlight and water are not available. Credits: JAXA / Honda

The core technology of CRES is a high differential pressure water electrolysis system, which electrolyzes water to produce high-pressure hydrogen and oxygen. Its is an evolution of Honda’s Power Creator technology, initially developed for fuel cell vehicles and hydrogen stations here on Earth, reflecting Honda’s broader commitment to carbon neutrality and sustainability.

Key technical specifications and advantages include:

  • Size and Weight: The electrolysis stack measures 420 mm tall and 210 mm wide, with the overall system at 980 mm tall, making it compact and lightweight, suitable for space transport where costs are approximately $700,000 per kilogram (delivered to the lunar surface).
  • Pressure Capability: It can store hydrogen at pressures up to 70 MPa, about 700 times Earth’s atmospheric pressure, enhancing storage efficiency.
  • Low Maintenance: The system requires no mechanical compressor, reducing complexity and maintenance needs in space.
  • Adaptability to Lunar Conditions: Engineered to withstand the Moon’s extreme environment, including temperature variations from 110°C during the day to -170°C at night, 1/6th Earth gravity, and high radiation levels.

Sierra Space, Honda, and Tec-Masters have formed a strategic partnership to test Honda’s high-differential pressure water electrolysis system on the International Space Station (ISS) facilitated be Sierra Space’s Dream Chaser spaceplane. Dream Chaser has a cargo capacity of over 6 tons and can return payloads to Earth at under 1.5g’s on commercial runways, enhancing its flexibility for space missions. The first Dream Chaser, named Tenacity, is currently undergoing final testing at NASA’s Kennedy Space Center for its ISS mission under NASA’s Commercial Resupply Services-2 (CRS-2) contract. The launch is currently planned for no earlier than the third quarter of this year, however, this first payload will not include Honda’s water electrolysis system. It has not been disclosed which upcoming Dream Chaser mission will transport the system to the ISS.

This testing aims to validate the system’s performance in space prior to operations on the Moon. Sierra Space will manage the mission, working with the Center for the Advancement of Science in Space (CASIS) and NASA, while Tec-Masters will handle payload integration, leveraging their extensive ISS experience. Tec-Masters brings decades of experience in ISS payload integration and certification, ensuring that the electrolysis system will meet stringent spaceflight requirements. The primary objectives of the testing will be to validate that the system can produce oxygen, hydrogen, and electricity reliably in space, crucial for future lunar base operations. This collaboration marks a significant step toward realizing Honda’s vision of sustainable energy systems for space exploration and could reduce the cost and complexity of lunar colonization.

In a Lunar Colony, CRES has the potential to enable a self-sustaining human presence on the Moon, given its ability for in situ resource utilization. Key applications include:

Oxygen Production for Life Support: CRES’s water electrolysis process produces oxygen as a primary output, which can be directly used to sustain colonists, reducing the need for oxygen transport from Earth.

Hydrogen as a Fuel Source: CRES can generate hydrogen as a versatile fuel for various lunar activities, including powering rovers, construction equipment, or spacecraft for cis-lunar operations or return missions to Earth. It can also be used in fuel cells to generate additional electricity, enhancing energy flexibility.

Electricity Generation: The electricity produced by CRES through fuel cells can power the colony’s operations, such as lighting, heating, life support systems, communication equipment, and scientific instruments. This is particularly valuable during the lunar night in lower latitudes, when solar panels can’t generate power due to the absence of sunlight for 14 days.

Closed-Loop Water Recycling: One of CRES’s most significant advantages is its closed-loop design, where water is continuously recycled. Water produced as a byproduct of fuel cell operation is returned to the electrolysis system, minimizing water loss. This is crucial for a lunar colony, where water is a scarce and expensive resource to transport from Earth.

The adoption of CRES in a lunar colony could significantly reduce the need for resupply missions from Earth, lowering costs and logistical complexity. By producing essential life support resources, fuel and electricity on-site, CRES could enable a sustainable lunar economy, supporting long-term habitation which could become a hub for further space exploration, such as missions to Mars.

However, challenges remain, particularly around sourcing water for the system. The quantity and accessibility of lunar water are still being researched, with estimates suggesting ice deposits may be small and dispersed, requiring advanced extraction technologies. Water on the Moon is primarily found in the form of ice deposited in permanently shadowed craters by comets and asteroids over billions of years, especially at the lunar poles, with additional water molecules embedded in lunar soil and rocks due to impingement of the solar wind. Recent research confirms that in addition to water ice in the polar regions, hydration has been found in lower latitude sunlit areas, suggesting a variety of viable sources for CRES. Extraction methods could involve heating lunar regolith to release water or mining ice deposits, though the scale and efficiency of these processes remain areas of active study. The energy required for water extraction and the system’s scalability for a large colony also need further investigation.

Honda’s CRES represents a transformative technology for lunar colonization, offering a pathway to self-sufficiency by leveraging local resources. Its testing on the ISS and eventual integration with lunar water harvesting operations position it as a cornerstone for future space settlement, though ongoing research into water availability and system scalability will be critical for its success.

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Design considerations for rotating space settlements

Illustration of a cylindrical rotating space settlement in Low Earth Orbit. Credits: Grok 3

A paper by German astrophysicist Rainer Rolffs titled Rotation of Space Habitats published last October has been uploaded to the National Space Society (NSS) Space Settlement Journal. The study aims to quantify how much structural mass is required to support both the artificial gravity and the internal pressures in various designs of a rotating habitat. It expands on previous work the author completed on energy flow in such habitats, integrating considerations of cooling, energy collection (via mirrors and photovoltaics), and the distribution of interior mass.

Habitat Geometry and Design Options
Rolffs analyzes several geometric configurations, including:
– Cylinder: A habitat rotating about its central axis, with design trade-offs between compactness and rotational stability.
– Tube: A cylindrical structure rotating perpendicular to its length, featuring rounded endcaps to ensure uniform gravity.
– Oblate Spheroid: A sphere that is flattened along the rotation axis, offering a different balance between structural mass and interior volume.
– Torus: A ring-like structure where the habitat’s thickness is a fraction of the overall rotational radius.
– Dumbbell and Dumbbell with Tube: Two-sphere configurations connected either by cables or a tube; these shapes offer flexibility in managing rotational radius and gravity distribution, especially at smaller scales.

Scaling and Habitat Sizing
The analysis scales the design by considering a constant interior volume per person, leading to a range of populations from very small (few individuals) to billions. Lower limits on habitat size are determined by constraints such as acceptable rotation rates (to maintain human comfort) and the mass needed for shielding against radiation. Upper limits are set by the challenges of maintaining co-rotation of critical components like mirrors for sunlight collection and the growing demands on structural integrity and cooling systems as size increases.

Gravity Distribution and Structural Considerations
The paper provides detailed methods to compute the gravity distribution inside the habitat by dividing the interior into floors with heights that vary inversely with gravity. Rolffs examines how the structural mass must not only counteract the centrifugal forces (to create artificial gravity) but also support the self-weight of the structure, with different methods for vertical (hanging) versus horizontal (standing) support. A “critical co-rotational radius” is introduced, beyond which certain components (like non-rotating mirrors or photovoltaics) can no longer be kept in co-rotation with the habitat without incurring prohibitive mass penalties.

Trade-Offs in Mass Budget and Optimization
Not surprisingly, shielding against radiation is identified as a dominant mass component for small habitats, while for larger habitats, the structural and cooling masses become more significant. The study shows that there exists an optimum size range—between tens of thousands and tens of millions of cubic meters of interior volume—where the payload (interior mass per person) dominates the overall mass budget, and the design can be optimized for cost and functionality. Rolffs finds that different shapes yield different trade-offs; for example, the dumbbell shape is preferable at smaller sizes due to its flexible rotational radius, whereas spheroidal shapes may offer lower structural mass for very large habitats.

Detailed Derivations and Appendices
The work includes extensive mathematical derivations provided in three appendices:
– Appendix A: Details the geometric parameters and derivations for determining the rotational radius and interior volume for each habitat shape.
– Appendix B: Focuses on the gravity distribution within the habitat, explaining how the artificial gravity varies across different floors and regions.
– Appendix C: Deals with structural integrity, deriving the requirements for supporting both the artificial gravity forces and the habitat’s own self-weight, including considerations for both vertical and horizontal support systems.

Rolffs’ analysis provides design guidelines that are critical for planning future space settlements, especially in the context of reducing launch costs and using in-situ resources (e.g., processed asteroid matter) for construction. He concludes that while very large habitats are theoretically possible (even accommodating populations in the billions), practical constraints related to cooling, light distribution, and structural integrity likely favor habitats in the medium-size range with optimized shapes such as the dumbbell or oblate spheroid.

Overall, Rolffs provides an in-depth exploration of the physical and engineering challenges associated with rotating space habitats, providing both theoretical foundations and practical design criteria that could inform future developments in space settlement engineering, earning the top spot on SSP’s Artificial Gravity Section as of this post.