Progress on inflatable lunar habitats

Conceptual illustration of a Moon base composed of inflatable habitats near one of the lunar poles. Credits: ESA / Pneumocell

The European Space Agency (ESA) recently published a report on a design study of an inflatable lunar habitat. The work was done by Austrian based Pneumocell in response to an ESA Open Space Innovation Platform campaign. The concept utilizes ultralight prefabricated structures that would be delivered to the desired location, inflated and then covered with regolith for radiation protection and thermal insulation. The main components of the habitat are toroidal greenhouses that are fed natural sunlight via a rotating mirror system that follow the sun. Since the dwellings are located at one of the lunar poles, horizontal illumination is available for most of the lunar night. Power is provided by photovoltaic arrays attached to the mirror assemblies. During short periods of darkness power is provided by batteries or fuel cells.

Cutaway view of the inflatable lunar habitat. Credits: ESA / Pneumocell

The detailed system study worked out engineering details of the most challenging elements including life support, power sources, temperature control, radiation protection and more. The greenhouses would provide sustenance and an environmentally controlled life support system for two inhabitants recycling everything. The authors claim that “…it appears possible to create in the long term a closed system…” This remains to be validated.

Inflatable space habitats have many advantages over rigid modules including lower weight, packaging efficiency, modularity and psychological benefit to the inhabitants because after deployment, the interior living space is much larger for a given mass. Several organizations and individuals have already begun to investigate inflatable habitats for lunar applications. The Pneumocell study mentions ESA’s Moon Village SOM-Architects concept which is a hybrid rigid and partly inflatable structure. Also referenced is the Foster’s and Partners Lunar Outpost design which envisions a 3D printed dome shaped shell formed over an inflatable enclosure.

Foster and Partners Lunar Outpost constructed from a hybrid of 3D printed modules and an inflatable structure. Credits: Foster and Partners

SSP previously covered another hybrid lunar inflatable structure designed by Rohith Dronadula. This design combines a collapsible rigid framework with an inflatable dome, can be autonomously launched from Earth and deployed through telepresence.

Illustration of a hybrid lunar inflatable structure. Credits: Rohith Dronadula

The Pneumocell report concludes: “A logical continuation of this study would be to build a prototype on Earth, which can be used to investigate various details of the suggested components … ” Such an approach would be relatively inexpensive and could inform the future design of flight hardware.

Speaking of ground based prototypes, The Space Development Network has been exploring inflatable structures for habitats on the Moon for some time. Doug Plata, president of the nonprofit organization working to advance space development hopes to display an inflatable version of his InstaBase concept at BocaChica, Texas when SpaceX attempts its first orbital launch of Starship, hopefully within the a year or so. When comparing his design to Pneumocell’s, Plata says in an email to SSP, “One difference is that we have the modules directly attached to each other and so avoid the mass of those connecting corridors.”

Conceptual illustration of InstaBase – a fully inflatable lunar base capable of supporting an initial crew of eight. Credits: The Space Development Network

In reference to the greenhouse designs, Plata continues: “As for the GreenHabs, they have a pretty interesting design to take advantage of direct sunlight. We address the shielding conceptually by fully covering the GreenHabs and then use PV solar drapes and transport the electricity into the GreenHabs via wires. By converting sunlight to electricity to LEDs, more surface area of plants can be grown than the surface area of the solar panels powering them. This is due to the full spectrum of the sun being converted to only those frequencies that plants use.”

It is great to see such creativity and variety of designs for abodes on the Moon. When reliable transportation systems such as Starship blaze the trail, we will be ready with easily deployable, safe and voluminous habitats for lunar settlements.

Artist rendering of the interior of an inflatable toroidal greenhouse in a lunar habitat. Credits: Pneumocell

Project RegoLight: Solar sintering lunar soil for 3D printed settlements on the Moon

RegoLight mobile printing head as implemented. Credits: RegoLight Consortium / Space Applications Services / International Astronautical Federation

Project RegoLight was an in situ resource utilization program funded by the European Commission to study automation of a process using solar energy to heat lunar soil to form building elements for a lunar settlement. The project ran from 2016 – 2018 and was intended to raise the technology readiness level from 3 to 5. The conclusions of the project were presented at the 69th International Astronautical Congress (IAC) held in Bremen, Germany in October 2018 and summarized in a report available on Academia.edu.

RegoLight had several primary objectives including automation of additive manufacturing of building elements under ambient conditions, fabrication of larger structures with a mobile printing head, demonstration of solar sintering under vacuum conditions, production of building elements using simulated lunar soil, material characterization of the building elements and other related processes in the context of a lunar settlement architecture. These activities would support plans for the Moon Village.

Conceptual view of an operational lunar base. Credits: RegoLight Consortium / LIQUIFER Systems Group / International Astronautical Federation

AIAA ASCENDxCo-Lab workshop identifies technology gaps for economically viable lunar settlements

Artist’s impression of a lunar settlement. Credit: ESA/Foster + Partners via universetoday.com

The 2020 virtual event sponsored by the American Institute of Aeronautics and Astronautics held in August brought together 200 space industry leaders from all over the world to discuss and respond to NASA’s ARTEMIS Plan. The event was summarized in a proceedings report that captured the group’s consensus on the technological and economic conditions needed for a sustained and economically viable lunar settlement. The attendees discussed the role of national space agencies, governments, and industry in addressing those conditions. The report defined a sustained lunar settlement as meeting the test of continuous survival and operation over time, and an economically viable settlement as one for which the long-term cost of maintenance is sustained by private capital.

When polled on the key technologies needed for a long term permanent presence on the Moon, the group identified the gaps in the chart below as those areas needing higher Technology Readiness Levels (TRL) to enable a permanent lunar settlement.

Technology areas needing further development. Credits: Jessica Todd et al.* / AIAA

The authors* then summarized the economic conditions identified at the workshop conducive to sustained lunar settlements, information needed to close the technology gaps and the roles of government space agencies as well as non-aerospace industries (e.g. healthcare, agriculture, food processing, utilities, mining and construction). _________________________________________________________________________________

* Authors of the ASCEND Ensuring Economically Viable Lunar Settlements Proceedings Report 2020 include:

Jessica Todd, Graduate Research Assistant, Aerospace Engineering in Autonomous Systems, Massachusetts Institute of Technology and the Woods Hole Oceanographic Research Institute
George Lordos, Ph.D. Candidate, Aeronautics and Astronautics, Massachusetts Institute of Technology
Becca Browder, Graduate Research Assistant, Aeronautics and Astronautics, Massachusetts Institute of Technology
Benjamin Martell, Graduate Research Assistant, Aeronautics and Astronautics, Massachusetts Institute of Technology
Cormac O’Neill, Graduate Research Assistant, Mechanical Engineering, Massachusetts Institute of Technology