Design solutions for safe lunar habitats

Artist’s impression of an inflatable habitat on the Moon. Credits / NASA, Gary Kitmacher

Haym Benroya, Distinguished Professor of Mechanical and Aerospace Engineering at Rutgers University and author of Turning Dust to Gold, Building a Future on the Moon and Mars gave a presentation recently at a workshop of the Engineering and Physical Sciences Research Council. EPSRC is the main funding body for engineering and physical sciences research in the UK. The event kicked of a project sponsored by the EPSRC called Designing for the Future: Optimizing the structural form of regolith-based monolithic vaults in low-gravity conditions. Benroya shared his presentation with me in which he discusses the design challenges and solutions to optimize a reliable and safe lunar habitat.

The design of space settlements on the Moon will have an array of engineering challenges including protection from radiation, meteoroids, temperature extremes and Moonquakes. In addition, human factors such as psychological and physiological aspects associated with isolation and the lower gravity conditions need to be taken into consideration. This presentation summarizes all the key design constraints, especially those surrounding the thermal and seismic conditions, laying the engineering groundwork for safe dwellings that will be erected when we return to the Moon, hopefully this time to stay and thrive.

For the technically inclined who want more information on lunar settlement design methodology be sure and check out Benroya’s excellent book Building Habitats on the Moon: Engineering Approaches to Lunar Settlements.

And don’t miss our appearance along with Dr. David Livingston of The Space Show and Moonwards‘ Kim Holder at the Icarus Interstellar 2017 Starship Congress.

When will the first human be born off Earth?

Space baby. Credits: scienceabc.com

One of the biggest challenges of space settlement facing humanity is procreation off world. We simply don’t know if its possible for a baby to be carried to term in less then one gravity. There are obvious ethical considerations of simply going there and trying it out. NASA is studying the problem but until we have a variable gravity centrifuge facility in space that will enable us to determine the “gravity prescription”, it will be a while before we have an answer.

In an article in The Space Review, Fred Nadis discusses some of the medical challenges of human reproduction in space and why one company, SpaceLife Origin, who’s mission was to enable human reproduction in space decided to suspend its planned missions for “Serious ethical, safety and medical concerns …”

These medical unknowns about reproduction in any gravitational field less then 1g is the obvious attraction of O’Neill type free space settlements which provide Earth normal gravity. But the huge scale and investment necessary to build such large scale settlements puts this approach far in the future. Al Globus thinks a better way might be to start with smaller spinning habitats in low earth orbit.

Asgardia’s has a key scientific goal of facilitating the first human childbirth in space which they believe is a crucial step on humanity’s “path to immortality as a species”. In preparation for that goal, the organization is creating the first sovereign nation in space. A good introduction to their plans can be found in an interview with Dr. Lena De Winne, the Head of Administration to the Head of Nation of Asgardia, who appeared on the Space Show recently.

Artist’s impression of the first human born in space. Credits: Asgardia

A map of the future of space enterprise

The Pathfinders’ Guide to the Space Enterprise. Credits: The Aerospace Corporation.

The Aerospace Corporation has created a visually stunning chart called “Pathfinders’ Guide to the Space Enterprise” in which they provide a glimpse into the nascent space economy based on hundreds of ideas from over 70 world-class space experts condensed into seven core themes about how the future could unfold. The analysis, which is both deep and thought provoking, identified two critical uncertainties shaping the the future of space development:

1. The degree in which space will be “commercialized.”
How much will space exploration and exploitation be designed to seed the commercial ecosystem?

2. The evolution and potential transformation of global power states.
What space-based leverage points could change the terrestrial power balance?

Their hope is to “…inspire your internal adventurer to think about how space can and will play a role in the future and how we get there.”

A simple inflatable Mars Habitat

Called “Space Nomad” the concept, conceived by Gábor Bihari at the University of Debrecen, Hungary and Thomas Herzig, CEO of Pneumocell Co., Vienna, Austria is described in paper available on Academia.edu. The elegant design takes into account the payload capacity of spacecraft of the near future and in situ resources available on Mars to arrive at a safe and feasible solution.

Artist’s rendering of a cross section of the Space Nomad habitat. This option of the settlement is made of several longitudinal inflatable tubes. The regolith ceiling protrudes to provide the proper shielding. The mirrors reflect sunlight into the structure all day. Credits: Gábor Bihari, Thomas Herzig

The main side wall is a tri-layer membrane with two gaps to provide insulation. The outer wall gap contains a vacuum and the inner one is gas-filled. The protruding ceiling provides shielding from radiation and protection from micrometeorites that impinge at high angles to the structure. The habitat is not completely closed as the design has a system for processing the Martian CO2 atmosphere, conditioning it for use by the greenhouses while producing breathable air and replenishing losses.

Artist’s illustration of the wall and roof structure of Space Nomad. Credits: Gábor Bihari, Thomas Herzig

A modified version of the habitat could be deployed at the Moon’s polar region as a preliminary step toward validation of the design before a Mars mission. Unlike the Mars settlement, this structure would have to be airtight and changes would be required to the mirror system.

Illustration of a modified circular version of Space Nomad as a proving ground for technology at the Moon’s polar region. Credits: Gábor Bihari, Thomas Herzig

Modular habitation system for human space exploration

Diagram of modular exploration system: pressure vessel, tertiary structures, power systems, EVA, and mobility. Credits: A. Scott Howe, Phd

At the 45th International Conference on Environmental Systems, A. Scott Howe, PhD presented a paper on a novel modular system for human habitation to support planetary and space exploration. The paper addresses the design requirements including mass and volume constraints to enable a variety of missions and environments. The concept was developed as recommended by NASA’s Evolvable Mars Campaign for a compact modular system and was assumed to be launched using the Space Launch System currently in the final stages of development. Howe settled on a horizontal module as the most appropriate with a single small diameter solution for fixed-sized habitats, expandable habitats, small rover cabins and a variety of other applications for both in-space and planetary surface operations.

Tired of messy lunar dust? Take an electron beam shower

Lunar dust caked on an astronaut’s space suit. Credits: NASA

Researchers at the University of Colorado at Bolder have discovered a promising method for cleaning lunar dust off of space suits and other surfaces likely to be contaminated on the Moon. The solution could be zapping the nasty grit with an electron beam.

Lunar dust sticks to just about everything because it acquires an electrostatic charge from the solar wind. By directing an electron beam at the surface contaminated with dust particles, an excess negative charge will build up resulting in the grains repelling each other and leaping off the surface where the beam is applied. Taking an electron beam shower may be how lunar settlers clean off before coming inside after walks on the Moon.

Lunar Cruiser: JAXA and Toyota name their rover

JAXA/Toyota Lunar Cruiser. Credits: Toyota

In a recent press release, the Japan Aerospace Exploration Agency (JAXA) and Toyota announced that they will name their crewed pressurized rover “Lunar Cruiser”. There have been some updates since we initially covered this topic. For instance, work this year progressed on simulations modeling power and heat dissipation while driving and the use of virtual reality to determine the layout of equipment in the vehicles’ cabin. In addition there have been discussions among over 100 partners in various industries of a “future lunar surface-based society” in an effort to “…gather the knowledge, experience and technological capabilities of enterprises from across a variety of industries in their attempt to realize their dream of sustaining continuous activities on the surface of the moon…”

Hopefully “Team Japan”, as the consortium is called, will take into consideration mitigation of the risks caused by lunar dust in the design and use studies of the Lunar Cruiser, as discussed in my presentation at the Moon Society’s Lunar Development Conference. At some point we hope to see the Lunar Cruiser navigating the network of roads that will hopefully be constructed as proposed by the Space Development Network. It may look like this:

EBIOS: toward closed-loop life support for space settlement

Artist rendering of EBIOS Experimental BIOregenerative Station. Credits: Interstellar Lab

Interstellar Lab has a mission to help build a future full of life on earth and beyond. To get started, the company plans modular villages on Earth designed as sealed facilities with environmental control and life support systems. EBIOS space-inspired communities will combine architecture, engineering, product design along with international collaboration in environmental science, agriculture, biochemistry, psychology and other disciplines. Each EBIOS will be a hospitality science center open to the public as well as scientists to facilitate awareness and needed research for self-sustaining space settlements. The company is developing methods and simulation software for integrated food production, water and waste systems to support human life in any environment.

Lunar Farming

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

A report called Lunar Agriculture, Farming for the Future was published this year by an international team of 27 students participating in the Southern Hemisphere Space Studies Program 2020 at the International Space University held at the University of South Australia. The report outlines the design of an early stage lunar farm housed in either partially or fully subsurface enclosures to mitigate risks from radiation, micrometeorite bombardment and extreme temperature swings. The settlement would be located near one of the Moon’s poles to take advantage of nearly constant exposure to sunlight and access to lunar ice.

The stated mission of the project was:

“To recommend and outline a vision for sustainable lunar agriculture that can suport the nutritional requirements of humans and allow them to thrive.”

The choice of crops were selected based on nutritional value as well as physiological and psychological needs. They included a variety of plants such as tomatoes, carrots, garden cress, sweet potatoes, soybeans, peanuts, rice, and oyster mushrooms. The team also included cloudberry cell cultures and insects (crickets) for protein on the menu.

Management of the settlement was envisioned to be governed by an international authority that would hew to the Outer Space Treaty.

Just for fun, compare this report to the article “Farming on the Moon” published 29 years ago in Volume 2 No. 3 of Space Colonization Progress available in the Vintage Section.

Lunar regolith beneficiation: a review of the latest research

Artist impression of a moon base. Credits: ESA

In the July Issue of Planetary and Space Science there is a summary of research on beneficiation, the process used for separation of minerals from waste in lunar regolith to prepare feedstock for chemical reactions to produce oxygen. One of the most commonly studied processes is hydrogen reduction of ilmenite (FeTiO3), a mineral abundant in the lunar maria. This type of research is critical to prepare for situ resource utilization (ISRU) needed for lunar settlements.

Benefication processes use differences in physical properties (e.g., density, electromagnetic characteristics) to manipulate materials, most commonly (especially on Earth) with water to facilitate separation. This is not practical in space environments where large scale water use will be more challenging then on Earth. On the Moon, dry techniques such as magnetic or electrostatic process are better suited to this application. The authors describe the physics behind the beneficiation process for ISRU in the lunar environment and survey the research performed thus far on these methods with interesting recommendations for further studies.