Billions in space: promise or mirage?
For several years, metallic asteroids have captured the imagination of scientists, entrepreneurs and investors. These celestial bodies are often described as floating mines, rich in iron, gold and platinum group metals (PGMs) – valuable elements for modern technologies, from catalytic converters to electronic devices.
The promise is attractive: to exploit these resources to meet growing global demand. But astronomical estimates of the value of asteroids – often in the billions or trillions of dollars – omit crucial details. They are in fact based on the unrealistic hypothesis that all the metal present in an asteroid could be extracted, transported and sold, without taking into account the titanic costs linked to exploitation.
In reality, technological, financial and logistical challenges make this idea much more complex. This does not mean, however, that this quest is in vain: pioneering research and initiatives are paving the way to a future where space exploitation could become a reality.
Which metals for which uses?
A recent study, funded by the start-up AstroForge and carried out by researchers at the Colorado School of Mines, revealed that metals from asteroids fall into two main categories: those with high added value, such as PGMs, which deserve to be be brought back to Earth, and those more common, such as iron and aluminum, which would find their use directly in space.
PGMs, such as platinum, palladium and rhodium, are extremely rare and expensive, with prices sometimes exceeding tens of thousands of dollars per kilogram. According to the study, asteroids actually contain concentrations much higher than those observed on Earth, particularly in metallic formations called refractory metal nuggets (RMN). These nuggets could contain quantities of precious metals several hundred times greater than those of terrestrial ores.
In contrast, common metals, such as iron or magnesium, would mainly be used in space. Building space infrastructure – orbital stations or lunar bases – with materials extracted directly from asteroids would avoid the prohibitive costs of transport from Earth, estimated at around $10,000 per kilogram.
Asteroid mining concept. Credits: NASA/Denise Watt
The challenges of space exploitation
While the idea of mining asteroids seems promising, it is hampered by many obstacles. Asteroids are not homogeneous deposits of pure metal: even formations rich in precious metals, such as NMRs, are often made up of microscopic particles that are difficult to extract and process.
In addition, the extraction of metals from space regolith requires complex and energy-intensive infrastructure. For example, industrial processes such as electrolysis of molten regolith, used to separate oxidized metals, require extremely high temperatures and considerable energy sources.
This chicken-and-egg paradox slows down the development of space exploitation: to build infrastructure capable of extracting these resources, materials and energy would already have to be available on site. Without advanced space logistics, these projects therefore remain limited by technology and costs.
AstroForge: pioneer of the rush to space
Despite the challenges, bold companies are embarking on this adventure, and AstroForge is one of the leading figures. Based in California, this start-up aims to make asteroid mining economically viable.
AstroForge began with pragmatic steps: funding scientific studies to better understand the composition of asteroids and planning experimental missions to near-Earth asteroids. These missions aim to answer key questions: what resources can really be exploited? Can we extract these metals with existing technologies? Do these celestial bodies contain enough wealth to justify investment?
AstroForge’s scientific and methodical approach, in collaboration with experts like those at the Colorado School of Mines, demonstrates a desire to move beyond speculation. However, nothing is guaranteed. The company will have to prove that its business model is feasible, while overcoming major technological challenges.
So, revolutionary future or distant dream?
In the short term, asteroid mining remains a colossal challenge. Exorbitant costs, lack of space infrastructure and the limitations of current technologies make it difficult to envisage profitable exploitation in the coming decades.
But in the long term, the prospects are more than attractive. If companies can overcome these obstacles, they could revolutionize access to resources. Precious metals could meet the growing demand for modern technologies, while common metals, mined directly in space, could enable the construction of gigantic infrastructures.
Imagine a future where lunar bases or Martian colonies are built with locally mined materials. Such space autonomy would reduce humanity’s dependence on Earth’s resources and pave the way for sustainable exploration of the universe.
To achieve this, two factors will be decisive: energy autonomy in space and automation of processes. Producing the energy needed to power extraction and processing infrastructures requires innovative solutions, such as space solar power plants or advanced nuclear reactors. At the same time, the development of robots capable of operating completely autonomously in hostile environments will be essential to limit costs and human risks.
Source : ScienceDirect
