Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space - Harrison Schmitt (Nov 2005)
No matter what the subject, one has to admire a book written by an astronaut and former US senator, illustrated with photos of the author at work on the Moon. When the subject is one as potentially important to the future of our civilization as the energy resources geologist Harrison ("Jack") Schmitt sees buried in the lunar surface, along with our future in space, it becomes all the more daunting to take issue with it. Unfortunately Schmitt's potentially inspiring commercial justification in Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space rests on a shaky foundation.
With NASA now planning a lunar return and several other countries planning missions, the time is certainly ripe for a book titled "Return to the Moon". In fact, last November also saw the release of Rick Tumlinson's collection of essays from experts on the subject, also titled Return to the Moon, and the Space Frontier Foundation has been running regular Return to the Moon conferences.
Schmitt's book acknowledges that context but sets out in his own direction, though one similar to that espoused by Dennis Wingo's "Moonrush", arguing that the Moon will provide a critical contribution to our civilization's energy needs, and the lunar return discussed is primarily one of industry and commerce, rather than grand national programs. The argument for industrial use of our celestial neighbor hinges on the utility of helium-3 fusion. However, that technology and the science behind it is dealt with in a perfunctory 4 pages in this book; Schmitt leaves the main argument to scientific papers from the University of Wisconsin Fusion technology Institute that has been promoting it.
Helium-3 fusion, while having the advantage of lower radiation levels, is considerably harder than deuterium-tritium (D-T) fusion: the extra proton in helium means the ideal fusion temperature for He3-D mixtures is over four times as large. An alternative hydrogen-boron reaction would require almost 10 times the D-T temperature. That makes the traditional approaches to fusion reactors, creating very hot and dense plasmas, essentially impractical for He3 fusion. Non-traditional inertial electrostatic confinement (for example "Farnsworth fusor") technology gets around the high temperature problem by essentially shooting the nuclei directly at one another in a steady-state fashion. In principle any kind of fusion is possible with such a design. However, in practice the maximum power output obtained so far is 1 Watt - you would need a hundred of them just to power a light bulb!
So that leaves a huge and unknown technology gap in scaling things a factor of 1 billion or so to power plant size. Schmitt lightly skips over this problem with the note that "much engineering research lies ahead" and then bases an economic analysis on the assumption that such a plant would have to compete with fossil-fuel plants; we know roughly the numbers there. This does provide real constraints on the costs of retrieval of He3 from the Moon, so it's a useful analysis. But there's still the fundamental question of whether He3 fusion could ever be economically practical.
Schmitt doesn't let those questions slow him down; cost estimates for the "much engineering research" piece are folded into capital cost estimates for building up to 15 fusion plants, building and launching (and staffing) 15 lunar mining settlements, and operational costs for the whole system to reach the conclusion that it could, after the 15th set of facilities was completed, be close to competitive with electric energy from coal. That's not a bad accomplishment, but it rests on a lot of assumptions of unstated but likely very high uncertainty.
Ironically, the best reason for replacing coal, the threat of global warming from atmospheric CO2 release, is given short shrift as an "international political issue" in Schmitt's introductory chapter on our energy future. In this and in a bias toward non-governmental solutions, Schmitt's text unfortunately betrays the caution of an incompletely recovered politician.
Organizational approaches are covered in detail in chapter 8, where Schmitt compares models ranging from all-government to various public/private partnerships, to an all-private approach, analyzing each model according to over two dozen financial, managerial, and external criteria. After giving each a 1 to 10 rating, he multiplies by another subjective weighting factor and adds them all up. Somehow, the all-private model wins every time. The text surrounding these numbers suggests that, despite what the numbers say, several of the public-private partnership approaches make a great deal of sense. This ranges from the Intelsat multilateral model to simply encouraging government funding of the necessary research, development, and testing, and passing technology on to private industry to earn a profit.
Schmitt's discussion of lessons from Apollo is almost reverential, including a proposal for a "Saturn VI" heavy-lift rocket, to lower launch costs. It seems unlikely that the Apollo conditions can be duplicated, but he does have an interesting argument in favor of in-house engineering talent and having a large pool of young engineers. This and the letters of chapter 10 are perhaps too bluntly put to have an impact on NASA directly, but could certainly help inspire organizational virtues in a private venture, so NASA's more recent mistakes aren't repeated.
There is much that is good here. The book covers some ideas in detail, including the lunar geology issues for helium-3 recovery. Designs for mining equipment, the idea of finding markets first in space, and only later on Earth, and the proposal to make the miners permanent settlers, rather than just temporary visitors are all interesting concepts developed here. The author has included copious citations for more in-depth reading.
Much of the infrastructure Schmitt calls for could be applied to any other commercial utilization of the Moon, for example to help develop solar power satellites or lunar solar power facilities, to provide lunar oxygen (or hydrogen) for in-space use, for lunar tourism, and so forth. Schmitt believes the He3 approach provides easier access to capital markets due to lower start-up costs, so less government involvement may be needed than for those other commercial justifications for a lunar return. However, the status of He3 fusion itself seems sufficiently uncertain that relying on private equity to make it happen could still be a very slow process, at least once development reaches the point of billion-dollar space missions.
This vision for a new day in lunar exploration is very different from what we have been hearing from NASA, even in recent years when a human lunar return has been on the table. There is considerable evidence we have an urgent need for new energy sources. The possibility of exploitation of the Moon for human benefit has hardly crossed public consciousness yet, but it's something that we will increasingly be turning to as humanity reaches limits here on Earth. We should all be grateful Dr. Schmitt has helped here to get that ball rolling.