This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Think you know about the Moon? I did, but then I started reading 'The New Moon: Water, Exploration, and Future Habitation' (Cambridge University Press, 2014) and realized that my knowledge amounted to a teensy scrap of lunar dust. For the past few years my colleague Prof. Arlin Crotts has been assembling an astonishingly detailed look at our satellite world - from its scientific history, to the history and future of its exploration. The result is eye-opening, and tantalizing, because it not only suggests that the Moon might be a vital part of where our species is going, it makes a compelling case that this is so.
I recently sat down with the author to discuss the book. Here is some of that conversation - ranging from lunar water to robotics, Soviet dirty tricks, gateways to the solar system, and even alien artifacts!
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Q: Why ‘New’ Moon?
Crotts: “The New Moon” reads better than “The Waning Gibbous Moon.” No, seriously… ;-)
There are many recent and revolutionary discoveries about the Moon, and we are only now coming to appreciate how they change our concepts about the Moon. For instance, there are at least a billion tons of water ice on the Moon, if not trillions. We also know now that there are extensive caverns or “lava tubes” just below the lunar surface. These might bear directly on how easily the Moon might be inhabited, and provide targets to be explored by remotely controlled robots. Unfortunately the lunar exploration program adopted by the United States in 2004 was abandoned in 2010, soon after these discoveries became apparent.
There are further revolutionary lunar discoveries, some bearing on water, that overturn 40-year old ideas about the development and structure of the Moon, and these offer new and interesting questions to explore. A flotilla of robotic probes, from the United States, China, Japan, India, European Union and Russia are beginning to scrape the surface in answering these. Since most spacefaring nations except the United States place the Moon at high priority in their list of mission destinations, how we might explore the Moon and its utility in supporting humans is increasingly relevant. There’s a lot of new stuff happening about the Moon.
Q: The book is a remarkable assemblage of lunar information and history. What took you by surprise as you did all of this research?
Crotts: I think every chapter has a surprise. In chapter one I just love describing unfamiliar ways in which the Moon influenced Earth, life and humanity. In chapter two, I dug out how the Soviet Union was employing dirty tricks trying to slow down the Apollo program at critical junctures. You wouldn’t read about a lot of that in the public domain, until this book. I write significantly about new things concerning water in and on the Moon, and I suggest how this could be applied to profitable lunar commerce in a few years and comparatively little expense. I think the thing most dramatic and overlooked is how easily the Moon might be turned into a permanent habitat for human beings, easier than any other place in the Solar System beyond Earth, and how many of these efficiencies about lunar habitats are not emphasized when people discuss putting humans there.
Q: The title includes the word ‘water’, not something most people associate with lunar science, why is that?
Crotts: Well, for forty years we “knew” that the Moon was dry, “dry as a bone,” while some of the samples from Apollo contained within them the evidence sufficient to show that this was not so. The fact that we know about the water now was due in part to better laboratory technology, but even more so to having become more open-minded about the question. For years scientists argued that water could not come from the lunar interior because this had been “baked out” in the horrific collision that formed the Moon and transformed Earth. On second thought, however, a dry Moon does not follow inevitably from this Giant Impact. As I describe in the book, it is likely that huge amounts of water reside in the Moon, even compared to the billion tons on its surface, and a logical expectation of this is huge amounts just below the surface, in conditions that humans and their machines might access in large quantity. We should probably be thinking of water more in trillions of tons.
Q: Would it be fair to say that the Moon is Earth’s last great wilderness?
Crotts: I describe the Moon almost as Earth’s last, wild continent, one that only 12 humans have actually reached, and for which we have direct information from over only about eight percent of its surface. We have the amazing advantage over the first explorers of the Earth’s poles or explorers of the Americas circa 1500 in that we have detailed and multi-channeled maps of the whole Moon, and know a lot about the areas we haven’t reached yet. Some of the most interesting aspects, such as water ice below the Moon’s surface or the environment of those lava caves I mentioned, are still unknown and must be explored by robot rovers and/or humans on the scene. The Moon is unique in this way because we can explore it with robots controlled from Earth with only a 3-second communication time delay, rather than many minutes or hours for any other Solar System body. I describe in the book quite a lot of what we know about how humans and robots can cope with exploring the Moon. There is a great era of lunar exploration still ahead of us. We must only choose to get started.
Q: You present some bold analyses and ideas about the Moon and our human future, care to explain?
Crotts: I like the concept of the Moon as a stepping stone, that what we will learn exploring the Moon will teach us a great deal about how to explore the asteroids, Mars and beyond e.g., dealing with dust, extreme temperatures, robotics and everyday needs. The Moon is also a great way station, even a refueling station, since lunar water can be easily broken into liquid oxygen and hydrogen, which together make some of the best rocket propellant around. No longer will we need rockets as big as a Saturn V, 111 meters tall, to send people to the Moon and back, or even bigger rockets (or the equivalent in many smaller rockets) to send people beyond to Mars and the asteroids. Instead a crew can visit a filling station in the vicinity of the Moon, bulk up on propellant and blast off to their destination without having carried all of that propellant mass, some 95% of the rocket in many cases. The Moon can open up the Solar System to us, such that humans can travel faster, not so susceptible to deadly radiation and other factors in long-range travel beyond Earth orbit.
There are so many unpredictable things that we might encounter on the Moon that the unexpected is a real factor. First, science experiments of an astronomical nature can open up whole new and intriguing vistas. Second, much of the lunar surface is old, relatively undisturbed for up to nearly four billion years, collecting from the Sun, Earth, interplanetary and even interstellar environments. Some people even talk about alien artifacts, much like they discussion radio searches for aliens, and the Moon might be the best place to look for these. If someday mining the lunar surface becomes profitable, which it might for several reasons that the book details, who knows what we might dig up? We should always keep science possibilities in mind even if we dig the Moon. The Moon is a great scientific and commercial resource, a precursor to other destinations but also full of surprises yet to come.