When asked a technical question about space exploration, I often respond, “I have a Poli Sci degree. I know nothing useful.”
I certainly felt that way while reading Asteroid Mining 101: Wealth for the New Space Economy by John S. Lewis.
Dr. Lewis is presently Chief Scientist at Deep Space Industries, one of two companies (along with Planetary Resources) planning to harvest asteroids and other celestial objects for commercial operations. A planetary scientist by education and profession, Dr. Lewis is Professor Emeritus of Planetary Sciences at the Lunar and Planetary Laboratory of the University of Arizona.
I was hoping this would be an introductory book for the technologically illiterate space commerce advocate such as myself, but apparently I was one book too late. In 1996, Dr. Lewis published Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets. To quote from a National Space Society review of Mining the Sky:
“Mining the Sky” is worth reading because it provides a justification and roadmap for incorporating the material and energy resources of our solar system into our world’s economy; and economic arguments may be the most long-lasting justifications for expanding our civilization into space.
But Asteroid Mining 101 is not at that level.
This book is not easy. It is serious and you will have to work a bit to understand all it has to offer. But if you do the work and spend the time you will graduate into the class of crazies who change the future — or at least understand us, and what is happening as we change tomorrow.
My Political Science degree started feeling a bit threadbare around page 25, when Dr. Lewis begins 75 pages of extremely technical discussion about asteroids and their mineral potential. Here's a random sample, from page 42:
Both silicon and magnesium react readily with oxygen to form stable oxides. The normal form of Si is as minerals containing the SiO2 molecular unit, and magnesium forms the MgO molecule. Iron, which has a relatively smaller affinity for oxygen, can form metallic Fe as well as oxides. In almost all meteorite groups, the most stable oxide of iron is FeO (ferrous oxide). The minerals these four elements form are metallic iron and the two very important “ferromagnesian” minerals pyroxene and olivine. Olivine is a solid solution of Mg2SiO4 (forsterite) and Fe2SiO4 (fayalite). The compositional extremes of any solid solution (here forsterite and fayalite) are called the end-members of the solid solution series. In meteorites with a low degree of oxidation, there is little FeO compared to MgO, producing olivine of nearly pure forsterite composition. Where FeO is more abundant (and where the amount of metallic iron has been proportionately reduced by partial oxidation to FeO) the relative amounts of FeO and MgO are closely comparable. Pyroxene is also formed by combination of SiO2, MgO and FeO. Pyroxene solid solutions of FeSiO3 (ferrosilite) and MgSiO3 (enstatite) are common; however, the pure FeSiO3 end member is slightly unstable in isolation, and does not exist in nature. Note also that, because of the strong lithophilic behavior of Si and Mg, the most abundant element in rocks by number of atoms is usually oxygen.
To quote from the classic Monty Python sketch, my brain hurts.
Throughout the book, some paragraphs run a half-page or more, which combined with the techno-jargon make for a very intimidating read. Having been a professional writer, I can tell you that one of the basics is to write short punchy sentences. It's easier to read, both to see and to comprehend.
After a while, I started skimming pages that were so technical as to be incomprehensible for the casual non-technical reader.
These chapters would be of more interest to a geologist, chemist or physicist with an interest in asteroid mining. If one of those fields is your expertise, then Dr. Lewis certainly gives you a lot to digest.
The graduate course in astrogeology eases up around page 100. (The main text ends at page 122, followed by two appendices totalling about 40 pages.) Chapter IX, Asteroid Mining and Processing, builds on all the technical information provided earlier in the book to discuss how all this can be executed.
An artist's concept of a fuel processor harvesting an asteroid. Image source: Deep Space Industries.
Although humanity has performed rendezvous and docking in cislunar space for almost fifty years, doing so with an asteroid is an entirely different skill. Dr. Lewis writes on page 101:
Not only do asteroids lack these civilized amenities, they are also wild beasts. Asteroids, especially those smaller than several hundred kilometers in diameter, are often extremely irregular in shape. Their surfaces are a chaotic patchwork of craters, rocks, rubble, and dust. Some areas may be large expanses of stainless steel; others may be deep loosely-packed regolith containing rocks of all sizes, and some may be extremely fragile and unstable “fairy castles” of fine-grained dust. In addition, asteroids rotate on their own schedule, not in accord with preplanned mission guidelines.
(The entire paragraph is more than a page long, broken only by a page break.)
For my education and interest, the generalist discussions of the economic practicalities of space commerce were the most important — not only for we liberal arts majors, but also for politicians and other decision makers who might be cajoled into investing government dollars in such future schemes.
Dr. Lewis, by this point in the book, has documented that because iron and nickel are so plentiful in asteroids, it makes sense to use them for construction in space, rather than returning those metals to Earth and launching them again.
He corrected a mistaken assumption I had, which is that platinum-group metals (PGMs) are plentiful in asteroids. They're not, but they can be extracted as byproducts from other harvesting operations. Dr. Lewis writes:
Among the byproducts of carbonyl extraction of iron and nickel are cobalt, platinum-group metals, and semiconductor nonmetals. Cobalt can be extracted by a variant of the carbonyl process and used to make high-temperature corrosion-resistant alloys for use in space. The Platinum-Group Metals (PGMs) made available as byproducts of iron, nickel, and cobalt extraction (platinum, osmium, iridium, rhodium, ruthenium and palladium) are sufficiently valuable to be worth returning to Earth. Two fundamental misconceptions about this scheme appear weekly in the press: that we will go into space primarily to mine PGMs for shipment to Earth, and that asteroids are a source of Rare Earth Elements (REEs). The first makes no economic sense: PGMs are a lucrative byproduct of a space-based ferrous metals industry. The second makes no chemical sense: the rare earths are not found in asteroidal native metal alloys, and indeed are not found in any plausible ore in any meteorite.
On Page 123, Dr. Lewis lists what useful products might be fabricated in space. On his list are:
- Radiation Shielding
- Structural Ferrous Metals
But let's not forget that space is vastly, hugely, mind-bogglingly big, to quote The Hitchhiker's Guide to the Galaxy. Asteroids need to be captured and returned to space factories where they will be harvested. The other option is to bring the factory to the asteroid, e.g. with a Bigelow Aerospace habitat, but still the asteroid has to be stabilized by stopping its spin.
Various NASA programs and proposals aim to develop these technologies, which could be transferred to the private sector. Dr. Lewis discusses the Asteroid Retrieval Mission (ARM) as originally proposed by the Keck Institute, which is the basis for NASA's Asteroid Initiative, as having limited potential to develop some of these useful technologies.
The purpose of this proposed mission is to establish ground truth on the physical and chemical nature of [a Near Earth Asteroid (NEA)] for planetary defense and economic utilization purposes, while also providing a science-rich exploration opportunity for manned missions. The retrieved asteroid, once parked in lunar orbit, would be the site of resource extraction experiments, but none of the products to be made there would be used in space operations.
This ambitious mission is not intended to serve as a model for future commercial missions dedicated to retrieving asteroid materials. The list of available targets is severely limited by the fact that the spacecraft cannot retrieve more than about 1000 tonnes. Asteroids of such low mass are typically about 7 meters in diameter. Such small bodies are so faint that they present almost impossible targets for spectral characterization: they must pass exceptionally close to Earth to be bright enough for spectral measurements. There is no way to determine their density and mass without a precursor spacecraft mission, and even that would be extremely demanding. But the retrieval mission would fail if the asteroid turned out to be denser and more massive than expected. This uncertainty drives the mission planners to target even smaller asteroids, for which the problems of mass and density determinations are even more severe.
I would like to see Dr. Lewis, his business partners at Deep Space Industries, their competitors at Planetary Resources and other experts such as retired astronaut Tom Jones unite to focus their efforts on a cogent, clearly articulated and compelling roadmap for creation of a robust asteroid mining and harvesting economy here in the United States. Using the successful commercial cargo and crew competitions as a model, NASA could offer incentives to companies, universities and entrepreneurs to develop the tools necessary to implement the vision laid out in this book by Dr. Lewis.
The United States is not the only nation capable of doing this, but the U.S. can do it long before its rivals if we put our minds to it.
Congress seems more interested in wasting billions of dollars on an Apollo redux with the Space Launch System and its Orion crew vehicle. Imagine what the $4 billion a year currently flushed into SLS/Orion could do to jump-start an asteroid mining economy.
Senator Ted Cruz (R-TX), the new chair of the Senate space subcommittee, has declared himself a big proponent of NewSpace. He might be the place to start, if this nascent industry could unite and persuade his office to hold a hearing to discuss the idea.
As Dr. Lewis writes, the International Space Station can be a testbed for some of these early technologies. Take advantage of it while we can.
I often talk to prospective engineering students, or their parents, about their potential future in commercial space. I encourage them to enter the field of robotics, knowing that this skill will be vital when the day comes that asteroid mining is a reality.
For those of a technical mind capable of understanding this book, I would strongly recommend it.
But if you graduated from college with a liberal arts degree ... this book will be a long hard slog for you.