The potential for space mining – including identifying asteroids close to Mars and Jupiter best suited for extracting precious metals and water – has been explored in a new study.
Research published in Monthly Notices of the Royal Astronomical Society looked into how viable the idea would be in the future.
Much is still unknown about the chemical composition of small asteroids but their potential to harbour valuable metals, materials from the early solar system, and the possibility of obtaining a geochemical record of their parent bodies makes them promising candidates for future use of space resources.
A team led by the Institute of Space Sciences (ICE-CSIC) in Spain analysed meteorites that had fallen to Earth, including from NASA’s Antarctic collection, to determine the chemical composition of the six most common groups of carbonaceous chondrites.
Their findings support the idea that these asteroids can serve as crucial material sources and identify their parent bodies, as well as for planning future missions and developing new technologies for resource exploitation.
Several proposals have already been put forward, such as capturing small asteroids that pass close to Earth and placing them in a circumlunar orbit for exploitation.
“For certain water-rich carbonaceous asteroids, extracting water for reuse seems more viable, either as fuel or as a primary resource for exploring other worlds,” said Dr Josep Trigo-Rodríguez, first author of the study and astrophysicist at ICE-CSIC, affiliated to the Institute of Space Studies of Catalonia (IEEC).
“This could also provide science with greater knowledge about certain bodies that could one day threaten our very existence. In the long term, we could even mine and shrink potentially hazardous asteroids so that they cease to be dangerous.”
Carbonaceous chondrites are relatively rare – making up just 5 per cent of meteorite falls – and many of them are so fragile that they fragment and are never recovered. Those that have been are usually found in desert regions, such as the Sahara or Antarctica.
“The scientific interest in each of these meteorites is that they sample small, undifferentiated asteroids, and provide valuable information on the chemical composition and evolutionary history of the bodies from which they originate,” Dr Trigo-Rodríguez explained.
Pau Grèbol Tomás, ICE-CSIC predoctoral researcher, said: “Studying and selecting these types of meteorites in our clean room and using other analytical techniques is fascinating, particularly because of the diversity of minerals and chemical elements they contain.
“However, most asteroids have relatively small abundances of precious elements, and therefore the objective of our study has been to understand to what extent their extraction would be viable.”
Study co-author Jordi Ibáñez-Insa, of the Geosciences Barcelona (GEO3BCN-CSIC), said: “Although most small asteroids have surfaces covered in fragmented material called regolith – and it would facilitate the return of small amounts of samples – developing large-scale collection systems to achieve clear benefits is a very different matter.
“In any case, it deserves to be explored because the search for resources in space would likely minimise the impact of mining activities on terrestrial ecosystems.”
Given the diversity present in the main asteroid belt, it is crucial to define what types of resources could be found there.
“They are small and quite heterogeneous objects, heavily influenced by their evolutionary history, particularly collisions and close approaches to the Sun,” said Dr Trigo-Rodríguez.
“If we are looking for water, there are certain asteroids from which hydrated carbonaceous chondrites originate, which, conversely, will have fewer metals in their native state.
“Let's not forget that, after 4.56 billion years since their formation, each asteroid has a different composition, as revealed by the study of chondritic meteorites.”
One of the study's conclusions is that mining undifferentiated asteroids – the primordial remnants of the solar system's formation considered the progenitor bodies of chondritic meteorites – is still far from viable.
On the other hand, the study points to a type of pristine asteroid with olivine and spinel bands as a potential target for mining. A comprehensive chemical analysis of carbonaceous chondrites is essential to identify promising targets for space mining.
However, the team states that this effort must be accompanied by new sample-return missions to verify the identity of the progenitor bodies.
“Alongside the progress represented by sample return missions, companies capable of taking decisive steps in the technological development necessary to extract and collect these materials under low-gravity conditions are truly needed,” Dr Trigo-Rodríguez added.
“The processing of these materials and the waste generated would also have a significant impact that should be quantified and properly mitigated.”
The team is confident of very short-term progress, given that the use of in-situ resources will be a key factor for future long-term missions to the Moon and Mars, reducing dependence on resupply from Earth.
In this regard, the authors point out that if water extraction were the goal, water-altered asteroids with a high concentration of water-bearing minerals should be selected. Exploiting these resources under low-gravity conditions requires the development of new extraction and processing techniques.
“It sounds like science fiction, but it also seemed like science fiction when the first sample return missions were being planned 30 years ago,” said Grèbol Tomàs.
The scientific team from ICE-CSIC selected, characterised, and provided the asteroid samples, which were analysed using mass spectrometry at the University of Castilla-La Mancha by Professor Jacinto Alonso-Azcárate.
This allowed them to determine the precise chemical abundances of the six most common classes of carbonaceous chondrites, fostering the discussion among the scientific community of whether their future extraction would be feasible.
The Asteroids, Comets, and Meteorites research group at ICE-CSIC investigates the physicochemical properties of the materials that make up the surfaces of asteroids and comets and has made numerous contributions in this field over the last decade.
“At ICE-CSIC and IEEC, we specialise in developing experiments to better understand the properties of these asteroids and how the physical processes that occur in space affect their nature and mineralogy,” said Dr Trigo-Rodríguez, who leads this group.
For over a decade he has been involved in selecting and requesting from NASA the carbonaceous chondrites analysed in this study, as well as devising several experiments with them.
"The work now being published is the culmination of that team effort," Dr Trigo-Rodríguez added.
ENDS
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Royal Astronomical Society
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Dr Robert Massey
Royal Astronomical Society
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Science contacts
Dr Josep Trigo-Rodríguez
ICE-CSIC
Images & captions
Carbonaceous chondrite meteorite
Caption: Reflected light image of a thin section of carbonaceous chondrite CV3 from NASA's Antarctic collection, analysed in the study. Several chondrules with bright olivine crystals embedded in a carbonaceous matrix can be seen.
Credit: J.M.Trigo-Rodríguez/ICE-CSIC
Further information
The paper ‘Assessing the metal and rare earth element mining potential of undifferentiated asteroids through the study of carbonaceous chondrites’ by J.M. Trigo-Rodríguez et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf1902.
Notes for editors
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