The concept of mining on the Moon has been around for decades, and while political and scientific endeavour has ebbed and flowed, it has never gone away. Almost all current space exploration programmes – American plans to go back to the Moon and Elon Musk’s SpaceX programme included – factor in mining resources in some way or another.
“The basic idea is to extract materials from the Moon that create new capabilities in space,” says lunar scientist Paul Spudis. “To this end, people have envisioned a wide variety of mining and resource utilisation activities on the Moon. Broadly, most plans involve the collection of granular material, running it through some type of processing, e.g. thermal, chemical – the extraction of useful stuff and the discarding of the waste.”
Scientific advances are bringing commercial space travel ever closer. At the same time, terrestrial resources are beginning to wane and dreams of making use of the 7.3 x 1022kg of material circling the Earth that make up the Moon have gained greater traction. So, realistically, how close are we to mining the Moon?
Water, metals and REMs
The Moon’s resources could be put to a number of uses, such as a source of fuel for farther flung journeys through space, or providing an alternate source of rare metals and minerals for use on Earth.
“There is a hierarchy of material resources, arranged according to their ease of acquisition and their utility,” says Spudis. “The easiest stuff is bulk regolith (lunar soil), which can be used to backfill installations on the moon and to make shielding to protect habitats thermally and from radiation.” Regolith would not be transported to Earth, but for missions such as SpaceX’s, which include building a lunar base, it could be very beneficial.
When, in 2008, samples from the 1970s Apollo 15 and 17 missions were re-examined, the presence of water brought greater hope of establishing lunar habitations. Since then, multiple studies have confirmed that the Moon has water in abundance. “Water ice (and other volatile substances) is found in the dark areas near the poles and have many uses, including life support and rocket propellant,” says Spudis. For any future mining activities water will be necessary, both for operations and for sustaining a crew.
“Water is the oil of the solar system and those companies who are able to harvest and harness extraterrestrial deposits of water will make Exxon look like a lemonade stand,” says founder and CEO of Moon Express, Robert Richards.
Along with water, the Moon has a number of other materials which would be useful for space exploration. “Metals can be extracted from the oxides in the soil by chemical reduction – iron, titanium and aluminium are the principal useful metals to be manufactured on the Moon,” says Spudis. But like regolith, it wouldn’t be profitable to bring these metals back to Earth where they can be mined far more easily.
Currently, China produces more than 90% of the rare earth metals (REM) we need for electronics. But reserves are running out fast with some elements, including dysprosium, neodymium and lanthanum, expected to be depleted within the next 20 years. In order to feed the world’s seemingly insatiable appetite for technology, new sources of REMs must be found, as recycling alone will be unable to meet demand.
“Rare and unusual elements and isotopes (rare earths, thorium, helium-3) may be accessed and mined,” says Spudis. “Some of these uncommon materials may be of such high value as to merit their importation back to Earth for sale in terrestrial markets. But these are in very low concentrations and will likely be the targets for mining in the future, after a long-term presence on the Moon has been established.” It is these which provide the greatest hope for profitable mining companies and shipping to Earth.
There and back again
Many hurdles remain before mining the Moon can happen, not least getting there. In all of human history only 12 people have ever walked on the Moon. This is, in part, due to the colossal expense of such a venture, so the cost must come down before industry can proceed. Conventional thinking is to create reusable rockets, something SpaceX is currently working on with its Dragon craft.
“If one can figure out how to effectively reuse rockets just like airplanes, the cost of access to space will be reduced by as much as a factor of a hundred,” says SpaceX founder and CEO Elon Musk. “A fully reusable vehicle has never been done before. That really is the fundamental breakthrough needed to revolutionise access to space.”
Once commercially affordable lunar transport has been developed and the Moon reached, then the challenges intensify. Crews working in the hostile environment of the Moon will have to endure living in “a vacuum with extremes of heat and cold, hard radiation and the ubiquitous presence of abrasive, angular dust grains”, explains Spudis.
The temperature on the Moon varies from 123°C to -233°C because there is no atmosphere, making human habitation and activities very difficult. Furthermore, there is only about a sixth of the gravity on the Moon that we experience on Earth, complicating mining operations substantially. Bases will need to be established, probably with the use of 3D printing, which would enable the construction of infrastructure on the Moon.
Mining lunar material will also require self-sufficient and reliable robotics to minimise human exposure to the Moon’s environment. “Mining machines could be automated for simple tasks and teleoperated for complex tasks requiring human supervision, but complex machines will require self-maintenance, high reliability and long lifetimes,” says Spudis. “The exposure of humans to the harsh environment must be minimised.”
Furthermore, raw materials harvested will need to be processed on the Moon. Transferring lunar soil to Earth for processing is simply impractical, and much of the materials would be required for activities taking place on the Moon itself, such as those necessary for building and maintaining the moon base.
For elements worth transporting back, there is a third phase of complications: returning to Earth. This particular challenge could be resolved by way of reusable space crafts, which would have to be capable of not only withstanding the immense heat and pressure of re-entering Earth’s atmosphere with enough control to land safely in a specific location, but to do all of this whilst carrying an extremely heavy cargo of REM.
In 2015, the US Commercial Space Launch Competitiveness Act was passed, supporting the private sector’s right to mine on the Moon. This has greatly increased the pace of efforts to reach and reap the rewards on offer.
“The natural resources of our solar system have great potential to facilitate and support our human endeavours, both in outer space and on Earth,” declared the chairman of the Science, Space and Technology Committee, Lamar Smith, at the time. “Commercial space companies in the United States are making significant investments to develop technical capabilities that will allow us to explore and use outer space resources.”
Companies such as Moon Express have been established with the hope of taking advantage of this previously untapped resource. Launching three missions over the next three years, it anticipates bringing back the first ever commercial Moon rock samples. Harvest Moon, its third mission, would mark the initial business phase for the company.
“We are now setting our sights on expanding Earth’s economic sphere to our eighth continent, the Moon, where vast resources have been deposited over billions of years of asteroid and comet bombardment,” said Richards.
Whilst not everyone is as optimistic that lunar mining will occur quite so speedily, it seems in no doubt that it will come to fruition. “I think that the simplest tasks will be undertaken within the next five-ten years,” says Spudis. “More complex operations (water ice harvesting, metal extraction) are likely within the next 20 years or so. Mining the rare materials is likely on 30-50 year timescales.”
Whether in three or 30 years time, mining on the Moon will have an enormous impact on space exploration, the REM sector and a multitude of other supporting industries. But, for now, it seems that plans rely upon establishing a cost-effective space transport system, perfecting reusable rockets, to bring us back to Earth.