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Room with a view on the Moon

Artist rendering of what could be the first hotel on the Moon. Credit: Galactic Resource Utilization Space

Galactic Resource Utilization (GRU) Space published a white paper in January outlining their ambitious plans for a combination lunar base and hotel on the Moon. They believe this plan will accelerate humanity’s transition to an interplanetary species. Authored by the founder of the startup Skyler Chan (a recent UC Berkeley graduate with experience in space hardware and software), the document critiques the current state of the space industry and proposes a private-sector-led approach centered on lunar tourism as the catalyst for broader infrastructure development. GRU Space, backed by Y Combinator, was founded last year.

Chan asserts that humanity stands at a pivotal moment where becoming an interplanetary civilization is achievable within our lifetimes. He argues that the current legacy space ecosystem relies heavily on two pillars: government-subsidized exploration (such as NASA’s Artemis program) and massive launch capabilities (e.g. the Space Launch System and SpaceX’s Starship). However, a true commercial “lunar economy” remains virtually nonexistent. The industry suffers from a stagnation cycle—companies wait for government contracts to fund development, while agencies demand proven hardware before committing funds. This creates a deadlock where advanced technologies (e.g. lunar robotics, power systems, comms) exist in isolation without real customers or demand drivers.

GRU Space rejects this dependency on slow government timelines and “customer discovery” phases. Instead, the company aims to create immediate, tangible value for people on Earth to jumpstart economic activity off-world. Their core thesis: space tourism, specifically a lunar hotel, is the fastest and most practical “wedge” to bootstrap a self-sustaining lunar economy. Chan’s proposed solution: GRU Space’s flagship project to build and operate the first hotel on the Moon, initially as a high-end tourism destination for short multi-day stays. This hotel would serve paying customers (with reservations already open for deposits ranging from $250,000 to $1 million) while simultaneously demonstrating and de-risking technologies essential for permanent lunar infrastructure. GRU’s innovations and phased approach include:

  • Mission I (2029): A small ~10 kg payload delivered via a Commercial Lunar Payload Services (CLPS) lander to test core habitation technologies, particularly an inflatable structure featuring an airtight bladder, structural fabric, micrometeoroid shielding, and thermal/UV protection layers.
  • Mission II (2031): Deployment of a lunar cave base using inflatable systems positioned near a lunar pit or lava tube skylight for natural radiation shielding and resource access. Although not in their current plans, this could pave the way for eventual pressurization of a lava tube for habitation, a concept that has already had preliminary studies completed and covered by SSP.
  • Mission III (2032): Delivery of the first operational lunar hotel via a heavy-lift launch vehicle and lander, accommodating up to four guests initially (with plans to scale to 10 in later versions) located in scenic locals, featuring stunning views of Earth and thrilling extravehicular activities.

The initial hotel will be constructed from inflatable modules shipped from Earth. Future expansions will transition to in-situ resource utilization (ISRU)—processing lunar regolith into durable bricks or structures using automated robotic systems. This reduces launch costs dramatically and enables scalable construction of roads, warehouses, mass drivers (proposed by Elon Musk recently), and other base elements including locally sourced oxygen. GRU’s team is staffed perfectly for these technologies. Cofounder and Member of Technical Staff Kevin Cannon is a planetary geologist and an authority on ISRU. He’s been the source for several posts on SSP and will know exactly where and how to access lunar resources needed for the effort.

The lunar hotel is envisioned to be a high-end destination that generates revenue from customers coming up from Earth, while simultaneously validating ISRU, habitation and life support technologies for more expansive infrastructure.

GRU Space’s broader vision after the hotel positions the company as an architect of long-term human presence on the Moon and Mars with a technical roadmap progressing as follows:

  • Solve the problem of off-world surface habitation via the hotel
  • Expand to support a full base with infrastructure including roads, resource processing, and storage.
  • Replicate the model for population centers on Mars for millions of people.

The approach leverages commercial transportation (e.g., from SpaceX or Blue Origin) and focuses on creating goods/services with Earth-side value (tourism experiences) to generate revenue and prove viability. This contrasts with government-led efforts by prioritizing private customers and rapid iteration.

Overall, the document combines technical roadmap details with economic philosophy, emphasizing self-reliance, revenue-driven development, and urgency in seizing the current window for interplanetary expansion. While ambitious and early-stage (with no operational hardware as of yet), it reflects a startup mindset applied to space settlement, backed by expertise in ISRU, robotics, and space systems from the founding team.

Chan concludes the white paper with a bold claim: by building the first lunar hotel, GRU Space will outflank the traditional space industry, create the initial spark for a lunar economy, and lay the groundwork for humanity’s multi-planetary future. He frames the project not merely as tourism but as a civilizational necessity—turning the Moon into a stepping stone for permanent, expanding human settlement beyond Earth. The last step in his “Top Secret” GRU Master Plan is humanity becoming a Kardashev Type III civilization! Now we know how he came up with the name!

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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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Engineering analysis of pressurized lunar lava tubes for human habitation

Conceptual illustration of a lunar base in Mare Tranquilitatis Hole, believed to be an entrance to a lava tube about 100 meters below the lunar surface. Credits: Dipl.-Ing. Werner Grandl

In a new paper in Acta Astronautica Raymond P. Martin, a propulsion test engineer at Blue Origin and Haym Benaroya, a professor of mechanical and aerospace engineering at Rutgers describe the former’s research he carried out as a graduate student under the latter analyzing the structural integrity of lunar lava tubes after pressurization with breathable air. As reported previously on SSP, subterranean lava tubes on the Moon and Mars hold much promise as naturally occurring enclosures that are believed to be structurally sound, thermally stable and would provide natural protection from micrometeoroids as well as radiation. If they could be sealed off for habitation and filled with breathable air, life could be simplified for colonists as they would not have to don space suits for routine activities.

“This paper makes the argument that … lunar lava tubes present the most readily available route to long-term human habitation of the Moon”

Two views of a lunar skylight revealing a potential subsurface lava tube in Mare Ingenii. Credit: NASA/Goddard Space Flight Center/Arizona State University

Martin opens the paper with a history of the discovery and physical characteristics of lunar lava tubes tapping geological data dating back to the Apollo program. The existence of a lava tube is sometimes revealed by the presence of a “skylight”, a location where the roof of the tube has collapsed, leaving a hole that can be observed from space. Using an engineering simulation software called ANSYS, he developed a computer model to assess the structural integrity of these formations when subjected to internal atmospheric pressure.

Martin creates a model for his simulation based on the morphology of a relatively small lava tube known to exist from imagery taken by the Chandrayaan-1 spacecraft, the first lunar probe launched by the Indian Space Research Organisation . This structure averages 120 meters in diameter and was chosen because it has a rille-type opening level to the surface and could be sealed off at two locations. This approach makes sense as a starting point because the cavern would be easy to access and less energy would be be required to pressurize a smaller enclosure. Thus, the amount of infrastructure needed to establish early settlements would be minimized.

The goal of the simulation was to assess the integrity of the enclosed space under varying roof thicknesses and pressurization levels. Failure conditions were defined using commonly employed methods of assessing stability of tunnels in civil engineering and based on lunar basaltic rock general material properties known from testing of samples brought back from the Moon in the Apollo program and lunar meteorites. Finally, a formula was derived for safety factors associated with the failure conditions to ensure robustness of the design.

When running the simulation over various roof thicknesses and internal pressures, an optimum solution was found indicating that it is possible to pressurize a lava tube with a roof thickness of 10 meters with breathable air at nearly a fully atmosphere while maintaining its structural integrity. This would would feel like sea level conditions to people living there.

Being able to pressurize a lava tube for habitation could significantly simplify operations on the Moon as the infrastructure needed to make surface dwellings safe from radiation, micrometeorite bombardment and thermal extremes would be extensive adding costs to the settlement.

“A habitat within a pressurized tube would offer large reductions in
weight, complexity, and shielding, as compared to surface habitats.”

Once a permanent settlement has been established and engineering knowledge advances to enable expansion into larger lava tubes, we can imagine how cities could be built within these spacious caverns, and what it would be like to live and work there. SSP explored just this scenario with Brian P. Dunn, who painted a scientifically accurate picture of such a future in Tube Town – Frontier, a hard science fiction book visualizing life beneath the surface of the Moon. Dunn envisions a thriving cislunar economy with factories producing spacecraft for Mars exploration.

Conceptual illustration of a spacecraft manufacturer inside a lava tube. Credit: Riley Dunn

Martin and Benaroya dedicated their paper to the memory of Brad Blair, a mining engineer who was a widely recognized authority on space resources.

The authors both appeared on The Space Show last December to share insights on this groundbreaking research. Benaroya has been featured previously on SSP with another of his graduate student’s (Rohith Dronadula) thesis on hybrid lunar inflatable structures.

Update March 16, 2023: Martin and Benaroya were featured in The Economist, via a recent licensed post in Yahoo Finance.

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Mars as breadbasket for the outer solar system

Artist’s rendering of a farming settlement on Mars. Credits: HP Mars Home Planet Rendering Challenge via International Business Times.

Space settlement will eventually require space farming to feed colonists and to provide life support. It’s clear that we will replicate our biosphere wherever we go. In that spirit, Bryce L. Meyer envisions Mars as the breadbasket of the outer solar system. In a presentation at Archon 45, a science fiction and fantasy convention held annually by St. Louis area fans, he makes the case for why the fourth planet would be the ideal spot to grow crops and feed an expanding population as part of the roadmap to agriculture in space.

Carbon dioxide and subsurface water ice are plentiful on Mars, critical inputs for crop photosynthesis. There is also evidence of lava tubes there which could provide an ideal growing environment protected from radiation, micrometeorite bombardment and temperature extremes. The regolith should provide good nutrients and there is already research on methods to filter out perchlorates, a toxic chemical compound in the Martian soil.

Image of Lava tubes on the surface of Mars as photographed by ESA’s Mars Express spacecraft. Credits: ESA/DLR/FU Berlin/G Neukum / NewScientist

Another advantage that Mars holds as a food production hub for the asteroids and beyond is its placement further out in the solar system. Since it is higher up in the sun’s gravity well, Meyer calculates that it would take less than 43% of the fuel needed to transport goods from Mars outward than from Earth. He even suggests that with its lower gravity and recent advancements in materials research, a space elevator at Mars could be economically feasible to cheaply and reliably transport foodstuff off the planet.

Meyer keeps a webpage featuring space agriculture, terraforming, and closed cycle microgravity farming where he poses the question “Why settle space?” I like his answer: “Trillions of Happy Smiling Babies!!!”

Basic input/output diagram of an environmental control and life support system like what would be expected in a space farm. Credits: Bryce L. Meyer

Meyer is the founder and CEO of Cyan React, LLC, a startup that designs compact photobioreactors and provides expertise in closed-cycle farming and life support especially for space settlement and space habitats. He is also a National Space Society Space Ambassador doing his part to educate the public about the potential benefits to humanity through the use of the bountiful resources in space. In a presentation at this year’s International Space Development Conference, he describes his research on bioreactors explaining how settlers will grow food and recycle waste sustainably on the high frontier.

Diagram depicting the flow of materials in a closed space farm habitat utilizing bioreactors. Credits: Bryce L. Meyer

Complete closure and stability of an environmental control and life support system (ECLSS) is challenging and not without limitations. As launch and space transportation costs come down in the near future and off-Earth supply chains become more reliable, complete closure will not be required at least initially. In situ resource utilization will provide replacement of some ECLSS consumables where available for colonists to live off the land. As missions go deeper into space reaching the limits of supply chain infrastructure and even out to the stars, closure of habitat ECLSS and resource planning will become more important. Meyer has done the math for farms in space to provide food and air for trillions of smiling babies…and their families as they move out into the solar system.

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Lava tubes big enough for large space settlements on the Moon and Mars

Image of Lava tubes on the surface of Mars as photographed by ESA’s Mars Express spacecraft. Credits: ESA/DLR/FU Berlin/G Neukum / NewScientist

Space advocates have long speculated that lava tubes on the Moon or Mars would provide an ideal protective enclosure for space settlements. The benefits include protection from radiation, micrometeorite bombardment, temperature extremes…the list goes on. Now, in a study published in Earth-Science Reviews, researchers at the the Universities of Bologna and Padua have found that lava tubes on these worlds could be 100 to 1000 times larger then on Earth, because of their lower gravity and the resultant effect on volcanism. Such roomy and stable subsurface chambers would be ideal for spacious space settlements.

Image of Olympus Town, a fictional colony built inside a lava tube on Mars from the National Geographic series of the same name. Credits: Framestore / Wired
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Moon Diver – robotic exploration of lunar lava tubes

At the 50th Lunar and Planetary Science Conference earlier this month, a paper was presented describing a mission concept for a two-wheeled tethered robotic rover to explore lava tubes on the Moon.  In addition to the scientific value of these windows into the lunar crust, lava tubes are ready-made natural structures that provide radiation protection, shielding from micrometeorites, and a shelter from the extreme temperature swings of the lunar surface.  Perfect for lunar settlements!

https://www.hou.usra.edu/meetings/lpsc2019/pdf/1163.pdf