Asteroid Mining Could Unlock Resources from Carbon-Rich Asteroids

A few years ago, asteroid mining was one of the most talked-about ideas in space exploration. As the commercial space industry expanded quickly, the prospect of commercialising space appeared to be drawing closer.

The concept of using platforms and spacecraft to rendezvous with and extract materials from Near-Earth Asteroids (NEAs), before transporting them to orbital foundries, ranked alongside ambitions to send commercial crews to Mars.

However, after extensive speculation and the collapse of several ventures, such schemes were put aside while the technology developed and other essential milestones were reached.

Asteroid mining and carbon-rich asteroids

Even so, the vision of asteroid mining and the “post-scarcity” future it might enable has persisted. Beyond the need for additional infrastructure and technological progress, scientists must carry out further research into the chemical makeup of small asteroids.

In a recent study, a team headed by researchers at the Institute of Space Sciences (ICE-CSIC) examined samples from C-type, or carbon-rich, asteroids. These objects represent 75% of known asteroids. The results indicate that they may offer an important supply of raw materials, creating possibilities for future resource extraction.

The team was led by Dr Josep M. Trigo-Rodríguez, a theoretical physicist at Barcelona’s Institute of Space Sciences (ICE) and Catalonian Institute of Space Studies (IEEC).

His collaborators included PhD student Pau Grèbol-Tomàs, also of ICE and IEEC; Dr Jordi Ibanez-Insa of Geosciences Barcelona; Professor Jacinto Alonso-Azcárate of the University of Castilla-La Mancha; and Professor Maria Gritsevich of the University of Helsinki and the Institute of Physics and Technology at Ural Federal University.

Their research is described in a paper due to appear on 2 January in the Monthly Notices of the Royal Astronomical Society (MNRAS).

Carbonaceous chondrites, known as C chondrites, regularly fall to Earth, but scientists seldom recover them for analysis. They make up only 5% of all meteorites, and their fragile structure frequently causes them to break apart and disappear. Most recovered examples so far have been discovered in desert environments, including the Sahara and Antarctica.

Trigo-Rodríguez leads ICE-CSIC’s Asteroids, Comets, and Meteorites research group, which studies the physicochemical characteristics of asteroids and comets. The group also serves as the international repository for NASA’s Antarctic meteorite collection.

For this study, the group chose and characterised asteroid samples before Professor Jacinto Alonso-Azcárate at the University of Castilla-La Mancha examined them using mass spectrometry.

Analysing the resources in C-type asteroids

The analysis established the exact chemical composition of the six most prevalent categories of C chondrite. This offers useful evidence on whether extracting their resources could become feasible. As Trigo-Rodríguez said in a Spanish National Research Council (CSIC) press release:

"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.

"At ICE-CSIC and IEEC, we specialize 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. The work now being published is the culmination of that team effort."

Establishing how much material asteroids contain is essential because they are extremely heterogeneous. Although they are generally divided into three types - C-type (carbonaceous), M-type (metallic) and S-type (silicaceous) - they are also categorised according to their spectral properties and orbits.

Asteroids are also, in essence, remnants of Solar System formation, shaped by a long evolutionary history of about 4.5 billion years. Determining their precise composition is therefore crucial for identifying where resources such as water and ores are most likely to be found.

The team’s findings suggest that extracting materials from undifferentiated asteroids, thought to be the parent bodies of chondritic meteorites, is far from practical. However, the study identified an asteroid type with abundant olivine and spinel bands as a possible mining target.

The researchers also stated that asteroids rich in water-bearing minerals and with high water concentrations should be prioritised. For now, they stress that more sample-return missions are necessary to confirm the identities of parent bodies before mining becomes a reality. Trigo-Rodríguez said:

"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. The processing of these materials and the waste generated would also have a significant impact that should be quantified and properly mitigated."

They argue that this will demand large-scale collection systems and techniques capable of extracting resources in microgravity.

"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 Trigo-Rodríguez.

"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."

Grèbol-Tomàs added:

"Studying and selecting these types of meteorites in our clean room 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.

"It sounds like science fiction, but it also seemed like science fiction when the first sample return missions were being planned thirty years ago."

The potential benefits of space resources

In any event, asteroid mining could offer substantial benefits, helping to explain why the topic attracted so much interest during the past decade. Alongside precious metals, many asteroids contain water ice that could be used to produce fuel for deep-space missions, as well as water for drinking and crop irrigation.

This could lessen dependence on supply missions from Earth and enable robotic and crewed expeditions to become more self-sufficient. Moving mining and manufacturing into cislunar space and the Main Asteroid Belt could also reduce the environmental effects of those industries on Earth.

Although public excitement around asteroid mining has declined during the past decade, numerous organisations are still researching and developing the required technologies. Space agencies including NASA and JAXA have likewise completed sample-return missions, revealing much about both the scientific value of asteroids and the materials they may hold.

In the near future, China’s Tianwen-2 mission will rendezvous with an NEA and a comet in the Main Asteroid Belt. A space-based resource industry may still be decades away, or even further off, but many are ready to be involved from its earliest stage.

Further reading: CSIC, MNRAS

This article was originally published by Universe Today. Read the original article.