| THE ONCE AND FUTURE MOON Paul D. Spudis Washington, DC: Smithsonian Institution Press, 1996 |
Rating: 5.0 High |
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| ISBN-13 978-1-56098-847-2 | ||||
| ISBN 1-56098-847-9 | 308pp. | SC/bwi | $25.00 | |
The Moon (Earth's natural satellite, Luna) is still a place of untold mystery — despite the wealth of scientific data obtained by the six Apollo expeditions that landed men on its surface, and by robotic probes sent on precursor missions — as well as the data from the paltry few probes we were able to launch after Apollo.
We know a great deal about the Moon's age, its composition, its past and present orbit. We have reasonably good theories of its formation and subsequent geological history. Yet many questions remain. Not only are there questions of basic science, such as the origin of many features on the lunar surface and the composition of its deep interior, but the tantalizing hints of large quantities of ice in permanently shadowed craters at the lunar poles, obtained by the Clementine and Lunar Prospector1 probes, suggest that establishing permanent bases will be easier than we thought — if and when we do go back.
Paul Spudis is a geologist and staff scientist at the Lunar and Planetary Institute in Houston, TX. He was deputy leader of the Clementine science team, and is thus eminently qualified to report on what that probe found when it passed the Moon in 1994. But he does much more in this book. Beginning with the ancient Greeks, he surveys the development of lunar science. Because so much of what we know flows from the Apollo-mission data, Spudis devotes the major portion of the text to that increment of discovery. I suspect that a geologist unacquainted with the subject would find the book a real page-turner. I also found it very readable, but there is a great deal of technical detail about the rock samples from each of the Apollo landing sites and what can be inferred from them. This was sometimes hard going.
Fortunately, Spudis is a capable writer. His explanations are clear, and the book provides plenty of photographs to illustrate them. But the best part of the narrative for me was his editorial comments. Here is a representative quotation [pp. 79-80].
The Apollo 15, 16, and 17 missions were outstanding successes by any objective measure. The Apollo program as a whole and these missions in particular form the cornerstone of our understanding of the Moon and its history. A nearly constant debate rages in the scientific community regarding the value of human spaceflight versus the unmanned robotic missions. The Apollo landings demonstrated that the difference, in capability and knowledge returned, between human exploration of the Moon and small robotic missions is comparable to the difference between a nuclear bomb and a firecracker. The manned Apollo missions revolutionized our understanding of the Moon and of planetary science, in a way that the unmanned robotic precursors did not and could not. The Apollo missions are lasting testimony to the value of people in the exploration of the solar system. – Pages 79-80 |
I have participated in this debate myself, albeit in a small way, and I am and have been on Dr. Spudis' side. It is important to hold up our side, because since Apollo the robotic missions have demonstrated their own spectacular successes: most notably, Voyager 1 & 2, and Pathfinder/Sojourner. Neither I nor Dr. Spudis would deny the worth of these endeavors. Yet what was the alternative? Not human missions; they would have been far too expensive. The alternative was no mission at all. Therefore it is disingenuous to claim, based on these latter-day missions, that robots return more and better science data than humans can. And it is an artificial dichotomy. If human missions were affordable, we would be seeing the proper balance of robot precursors followed by human crews — just as we saw with Apollo.
There is a larger and no less inflammatory debate. That concerns the value of space exploration itself. Dr. Spudis also understands this debate well, and frames it correctly, as witness the following [pp. 245-246]:
The absence of any long-term view of what we should be doing for the future — our attitude about the future — is a failure of vision. In the United States of the 1960s, we were confident that the future held great promise, even if we did not know what form that better, brighter future would take. When President John F. Kennedy issued his challenge to go to the Moon and do it within a decade, the nation and Congress were eager to respond, ... – Pages 245-6 |
Although I would have worded this differently, in essence it is an accurate assessment. Present problems, real or perceived, have come to dominate our thinking, to the extent that some even argue against any use of government funds that does not address the crisis of the moment.
Dr. Spudis also writes of a failure of nerve, and perhaps this underlies the failure of vision. Yet given a suitable challenge, with well-defined rewards in the offing, we as a nation would find our courage again. Dr. Spudis devotes the last four chapters of his book to defining such a challenge. Simply put, it is a permanent return to the Moon. The rewards are several: First, a deeper scientific knowledge of the Moon; second, access to lunar resources, probably including large quantities of water at the poles; third, a stable platform for optical and radio astronomy on farside; fourth, a site for less costly launch of missions to the rest of the solar system.
A set of useful appendices complements the text, followed by a glossary, an annotated bibliography, and a reasonably detailed index.
I noted a few possible errors. On page 152, he writes that "In addition, regolith breccias contain solar wind gases, such as hydrogen and helium, and the rare gases argon, krypton, and neon." Omitted is xenon, which is in fact lighter and less rare than krypton. (In terms of atomic weight, the noble gases run: Helium, neon, argon, xenon, krypton. One would expect their concentrations to go the opposite way. Thus, this may merely be due to a failure to detect xenon in these particular samples. Krypton would be even scarcer, of course — but krypton is radioactive.) On page 211, he says, "However, when privacy is desired, the far side is as physically isolated as one can get and still remain within the solar system." I would quibble with this, too. I suppose it depends on what "isolated" means. The lunar far side is out of sight of Earth (and out of direct radio contact), so it certainly provides a sense of isolation. But a radio relay is easily set up, and travel time from the home planet is only a few days. To me, therefore, true physical isolation is found farther out. Pluto, say. Now that's isolation. And I could not discern the overall meaning of the chart on page 51.
Dr. Spudis had a good editor; there are not many typos. There is a space missing2, 3 on page 66: "This supposition was supported by the chemical analysisthat the Surveyor 7 spacecraft made of Tycho ejecta..." And on page 251 the book refers to the "Semiconducting Supercollider"
This is, in my judgement, a vital book — not for the science or the history, which are both fascinating, but for its contribution to the debates mentioned above. A great deal of future history (and future science) will depend on who wins those debates.
To contact Chris Winter, send email to this address.