I spend a fair amount of time discussing space development with people, in presentations, blogs, and in personal conversations. Most people who know me know that one of my prime foci is off planet industrialization, principally beginning with orbital space and then the Moon. One of the most baffling and tragic responses that I get in this realm is the complete dismissal of the entire concept. The back and forth in someone else’s blog thread is never satisfying because you cannot develop more than a short stream of thought and when the other person/persons are simply dismissive, no real progress is made. Thus in this missive I am going to go into some of my basic thoughts regarding lunar industrialization and see if we can get beyond these, in my opinion, misunderstandings regarding how hard it is.
As is my way in developing these ideas lets begin with how things are done here on the Earth and then see how they might develop on the Moon. I always look at history as a guide. I grew up near Birmingham Alabama, then called “The Pittsburg of the South”. Some of my earliest memories are of riding in a car by the big steel mills in Ensley, Fairfield, and downtown (Sloss furnaces) Alabama.
These places always fascinated me as you could see the hot steel ingots being stamped, rolled, and worked from the car. At Sloss you could see the hot steel being poured from the ladles into molds. Many of my friends that I grew up with now work at steel mills like Fairfield, ACIPCO, O’Neal Steel, and others. While I have not worked at any of these myself, I know a pretty good bit about them and have used their products in hardware that we have built, such as our 22,500 lb steel solar/wind trailers. Figure 1 is a picture of the frame of our solar/wind trailer under construction:
The trailer under construction in the picture above is made from standard A-36 steel. The frame parts are made from tube, “c” channel, flat plate, and square tubes. All of these parts are welded together using very simple frames, c clamps, and other devices to hold the pieces together while they are welded. This principle is pretty much how most heavy equipment is built, with the larger production lines being more automated. The pieces here came from a steel distributor and were cut into the right lengths/sizes using laser and or plasma cutters.
This background is provided in order to convey to the reader a small sense of my history with steel as well as a bit of information on how vehicles are put together in a low production environment. There is nothing magic about how this is done, just simple steel products welded together by competent people who do this as a living. I love metals and have spent a lot of my life around heavy equipment and its uses, especially in the coal mining industry. Thus I can at least speak with some knowledge of the subject here on the Earth. The interesting part is how to translate this to how we would do such things on the Moon.
Basic Things Needed for Lunar Industrialization
There are four basic things needed for basic lunar industrialization.
- Raw Materials
- Manufacturing Infrastructure
Availability of Lunar Metals
It is well known from the literature (one example) on the Apollo samples (the greatest part of their legacy) that there is meteoric metals and nano phase iron in proportions up to 1%. Apollo 16 samples, being from a highlands site has the greatest proportion of meteoric materials, which is to be expected as the highlands have the oldest regolith. Thus if we were to do the most minimal processing of highlands regolith from a site at the North pole (my favored location for many reasons), then we can expect to obtain quite a bit of metal. Beneficiation, or concentrating, of this metal could be accomplished on the Moon with nothing more than an electromagnet and a dump truck rover. There is absolutely no reason whatsoever that a robotic rover with a magnet could not pick up a minimum of 100 kilograms per hour of this meteoric metal. This can be done without any of the exotic chemical or other methods of separating metals from their oxides on the Moon.
Melting and Forming the Metal
There are different ways of melting metal but they all require energy. For the Moon there are two easy ways to do it. The first way is to simply use the sun and all you need to do it is a fresnel lens. Here is a video of a guy who does just that, with a very simple and lightweight system:
Here is a second and much faster method using a parabolic mirror:
If you notice the video closely you will see that they only used a small fraction of the available light on the parabolic mirror to melt the steel. At the lunar north pole where up to 100% of the time it is sunlit (Northern hemisphere summer) there is plenty of sun to support a continuous operating foundry.
The second means, using indirect sunlight in the form of electrical power, is achieved by using an induction furnace. The next video shows that:
So what we have here are two different methods of melting metals that would be directly applicable to melting metals on the Moon, even with a lot of rock contamination, which since rock is lighter, floats to the top and is scooped off as slag.
The next video shows metal pouring and forming. The sand mold method of metal casting is as old as the Hittite empire, long before Rome. The video here is from a British television program called “Metal Monkeys”.
Remember at the beginning of this article where in figure one the trailer is made from welded pieces of steel? It is quite simple using the sand mold process to make the basic parts that go into the trailer frame construction. On the Moon it would be done using sintering of the regolith using microwaves after forming the desired part: Figure 2 shows my concept of the induction furnace and mold that would be used to build structures on the Moon:
Uses of Metal On the Moon
There is no end of the uses of metal on the Moon. For simple parts and objects the manufacturing infrastructure is minimal. All that was used in the construction of our trailers in figure 1 was saw horses to hold the frame, C clamps to hold the pieces together while they are tacked together, and then a bridge crane to lift the assembly and turn it over during the production process. Obviously you need a welder as well, but on the Moon welding is very easy and you could use a laser welder, which requires a lot of power but little in the way of consumables or good old concentrated sunlight again.
Figure 3 shows an Eagle Engineering design of the LOTRAN rover on the Moon:
Figure four below shows a lunar habitat with structure holding up the weight of the regolith radiation shielding:
In figure 3 and 4 there are many of the structural pieces that, rather than being brought up from the Earth, could be derived from local ISRU derived metals. Even the habitats themselves could be made mostly from locally derived metals. There is a class of steel called “Maraging Steel” that is a high nickel alloy that is very close to what you would have available from meteoric and nano phase iron derived from the regolith.
Slaying Sacred Space Cows With a Gestalt Tempered Blade
One of the sacred cows that drives the demand for a heavy lift vehicle is that ISRU is not ready for prime time, that it is too hard, and that it is something that will happen in 20, 50, or 100 years, pick your time. A friend of mine who was on the Augustine II commission told me that Norm Augustine simply would not allow any discussion of ISRU as an enabling technology for transforming the Constellation program. He said that he simply did not believe it was possible. In another blog forum recently when I brought up the possibility of making rover parts from ISRU derive metal, the person I was interacting with simply refused to carry on the conversation as for me to even mention that was to shift the discussion into the non-credible.
After reading this somewhat long post I hope that the reader will get the idea that obtaining, melting, and forming metal is no big deal. As someone who grew up with and continues to work with steel I find it astonishing when otherwise intelligent people simply dismiss the possibility with a wave of the hand. There is absolutely nothing precluding a metals centric ISRU implementation on the Moon that would have an immediate upstream effect on the entire architecture for lunar/Mars exploration.
In all of the discussions about heavy lift, I have never been able to find anyone who can list more than a few payloads that require a heavy lifter. These are things such as a habitats, pressurized rovers, power systems, and humans. With a robust implementation of ISRU coupled with the landing of modest equipment with existing vehicles, the need for heavy lift is completely eliminated.
That is a sacred cow worth slaying…