Off-Earth manufacturing: using local resources to build a new home
Humanity is heading back to the Moon, and this time, we're planning to stay. But for long-term space missions, astronauts would need infrastructure to live and work, to move around, to communicate with Earth, and to produce oxygen and water vital for survival.
Taking all this infrastructure from Earth would likely be prohibitively expensive. Instead, we need to figure out how to make it on site. ESA Discovery & Preparation has supported many studies to explore how we can do this.
Using local materials to build infrastructure and produce amenities is known as in-situ resource utilisation (ISRU). Past research in this area has explored and demonstrated fundamental ISRU concepts using a combination of resources found on the exploration site and materials brought from Earth.
ISRU is needed to build a habitat that shields astronauts from harsh environments including thin or non-existent atmospheres, extreme temperatures, intense radiation and even micrometeoroids. It would enable us to build roads to move around the surface, and launch and landing pads for travelling to and from Earth. It could be used to produce equipment that can generate and store energy for producing electricity, as well as antenna towers for communication. And it could produce huge amounts of water and oxygen for keeping astronauts alive and creating propellants for travelling around and eventually coming back to Earth.
What is Discovery & Preparation doing in this area?
In 1999, one of the first ISRU-related Discovery & Preparation studies concluded that ISRU could reduce the costs of missions to Mars whilst increasing our capabilities, but that research and development in ISRU technologies should begin right away. And so, in coordination with all ESA programmes, research continued. A study completed in 2000 focused on the power systems required for future space exploration, including designing an ISRU chemical plant to produce propellant, chemicals for life support, and fuel for surface activities.
Other studies happening at the same time took a broader look at long-term space exploration, with one considering what architectures and technologies would be required for Mars exploration. The study investigated the possibility of producing propellant and fluids necessary for crew survival from the Martian atmosphere and soil. Another study on the survivability and adaptability of humans to long-duration interplanetary and planetary environments also found that ISRU could be particularly useful for producing propellants and life support consumables.
Fast forwarding 13 years, the technology had developed enough to explore more specific ISRU concepts, including a system to collect and store carbon dioxide from the Martian atmosphere and deliver it to a propulsion system. The study suggested ways in which dust and water could be separated from the carbon dioxide, as well as how it could be liquified for storage.
Over the last few years, Discovery & Preparation has supported more research into building infrastructure using lunar soil. A 2009–2010 study laid the groundwork for this; it confirmed the suitability of lunar soil as a building material, selected a suitable process for printing structures from it, and even designed a printable habitat. More recent studies have gone a step further, with one exploring how any necessary structures, equipment and spare parts could be 3D printed using lunar regolith – even selecting which specific printing processes would work best, and another investigating how best to process lunar soil to make it a useful input material for 3D printing.
Lunar soil could also be used in other ways; in 2019, both Azimut Space and the Technical University of Catalonia explored how it could store heat and provide electricity for astronauts, rovers and landers.
But taking ISRU technologies to the Moon is challenging, so it is useful to test them first on Earth. Space Applications Services investigated how lunar analogue facilities could support the development of ISRU technologies – including testing the excavation and processing of local materials, as well as how these materials could be used to build structures using processes like 3D printing.
As an alternative to existing 3D printing technologies, a 2019 study looked into turning lunar soil into fibres to build strong structures; the researchers showed that it is possible to use this process to make structures that are locally impermeable. A later study also created fibres from different types of lunar rock simulants. Another alternative could be to take an inflatable habitat that could be filled with air on the Moon – a study by Pneumocell looked into exactly this.
A set of Discovery & Preparation studies also explored and defined ESA’s lunar IRSU demonstration mission, which aims to prove that producing water or oxygen on the Moon is possible. One study looked into the system proposed a package that extracts oxygen from the soil and uses it to produce water. Another explored how the system could rely on a lander as a power supply and a third investigated how it could communicate with Earth.
In recent years, Discovery has pushed even further into the realm of ISRU. In 2019 the programme sought ideas for enabling technologies for in-situ construction, manufacturing and maintenance of infrastructure and hardware to support long-term exploration of a planetary body. 23 activities were selected for funding: together they support the construction of habitats, mobility infrastructure (e.g. roads and landing pads), ancillary infrastructure (e.g. for communication and energy generation and storage), and hardware (e.g. tools, interior equipment, machinery and clothing). From constructing human habitats in underground lunar lava tubes to 3D printing tiny ceramic parts, read the results of all the completed activities here.
What else is ESA doing?
To support the ambition to have a human presence on the Moon sustained by local resources by 2040, in May 2019, ESA published its Space Resources Strategy. The strategy considers what we need to discover and develop to support sustainable space exploration. It covers the period up to 2030, by which time the potential of lunar resources will have been established through measurements at the Moon, key technologies will have been developed and demonstrated and a plan for their introduction into international mission architectures will have been defined. Following the publication of the strategy, ESA hosted a workshop to identify the next steps needed to make space resource utilisation a reality.
In 2023, ESA called for ideas to accelerate ISRU, focusing in particular on: excavation, refining and transportation; resource extraction and processing; and storage, distribution and utilisation. As of August 2023, the ideas are being evaluated and the identified gaps in IRSU will serve as the basis to define the themes of the next ESA and ESRIC Space Resources Challenges.
More specifically, ESA is currently working on Prospect, a robotic drill and miniature laboratory that will access and assess potential resources on the Moon to prepare for the technologies that may be used to extract these resources in the future. Prospect will drill beneath the Moon’s surface near its South Pole and extract samples expected to contain frozen water and other chemicals that can become trapped at extremely low temperatures. The drill will then pass the samples to a chemical laboratory where they will be heated to extract these chemicals. The package will operate as part of the Russian-led Luna-27 mission and will test processes that could be applied to resource extraction in the future.
In 2020, ESA set up a prototype plant to produce oxygen out of simulated moondust. Removing the oxygen from lunar soil leaves various metals; another line of research, therefore, is to see what are the most useful alloys that could be produced from them, and how they could be used on the Moon. The ultimate aim would be to design a 'pilot plant' that could operate sustainably on the Moon, with the first technology demonstration targeted for the mid-2020s.
What are other space agencies doing in this area?
NASA's Lunar Surface Innovation Initiative is developing technologies for future human and robotic lunar exploration, with a capability area dedicated to ISRU. For example, its Polar Resources Ice Mining Experiment-1 (PRIME-1) will be the first instrument suite planned to land at a lunar pole to assess volatiles and determine water content.
NASA's first Mars lander, Viking, returned important data about the Martian atmosphere, revealing that it is made up of 95.9 percent carbon dioxide. Based on this discovery and information returned by subsequent robotic missions, the Agency has developed technologies to convert Mars' atmospheric carbon dioxide into oxygen to benefit human missions to the red planet. The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) is one of seven instruments on board the Mars 2020 Perseverance rover.
Volatiles are substances that vaporise easily and could be a source of water on the Moon. Together with other space agencies, NASA is conducting an international coordination of lunar polar volatiles exploration to increase scientific knowledge, determine the viability of volatiles as potential resources, and to use the Moon as a proving ground for Mars ISRU technologies.
Future China National Space Administration missions are also expected to target lunar polar volatiles as potential resources. China's vision of an international lunar research station, to be established initially as a robotic facility for science and research during the late 2020s and early 2030s may provide an early opportunity for lunar resources to be utilised.
The Russian space agency, Roscosmos, is working with ESA on the series of three Luna missions, including Luna-27, which will host ESA's PROSPECT package. The mission will target measurements in the polar region of the Moon, focusing on cold trapped volatiles that may be found there.
What's next at ESA?
The use of space resources for exploration is now within reach thanks to advances in our knowledge and understanding of the Moon and asteroids, increased international and private sector engagement in space technologies, and the emergence of new technologies.
Developing technologies and methods to use local resources to support future astronauts remains a challenge, but in doing so we are stimulating innovation on Earth through technology needs as well as new approaches to managing limited resources. This will hopefully help us find new ways to address global challenges and generate near to mid-term economic returns for terrestrial industries.
Last updated 17 August 2023
