The fourth annual lunar science conference convened on March 5, 1973, with more than 700 scientists in attendance.7 NASA's Deputy Administrator, George Low, opened the four-day meeting by reviewing the Apollo lunar exploration program and the progress made in understanding of the moon in three and a half years. He expressed NASA's gratification with the willingness of the scientific community to participate effectively in analyzing the data and planning the succeeding missions, citing the Group for Lunar Exploration Planning and the Science Working Panels, the support provided during the missions by the scientists in the back rooms, and the help others had given in training the crews and selecting sites. Low told the group that NASA was "firmly committed" to continue support of lunar studies based on the Apollo samples.8
Few results from Apollo 17 were presented at the conference, since so little time had elapsed since the samples were released. One of the first studies had determined that the orange soil, which consisted mostly of tiny beads of brown to reddish glass of a composition similar to lunar basalts, was probably of volcanic origin. While it could also be explained as the product of a meteorite impact, the soil was age-dated at 3.5 to 3.7 billion years, an age that could not be correlated with any major basin-forming event and therefore with any major impact.9 Other papers at the conference reported basic data on the nature, chemistry, and ages of the Apollo 17 samples that had been released.10
While analysis of lunar data continued unabated (the proceedings of the fourth lunar science conference, like those of the three before it, filled three large volumes) by early 1973 the major constraints to a model of lunar evolution were beginning to be clear. Geological, geochemical, and geophysical evidence made it clear that the moon is quite different from the earth in structure and composition and therefore probably in the process of its formation.11 A coherent picture of the moon's history gradually emerged over the next few years (see below).
This conference marked the end of Apollo's voyages, and perhaps that was responsible for the "notable spirit of amity between lunar scientists and NASA's engineer-managers" that some observers perceived at the meeting. In response to George Low's acknowledgement of their contributions to Apollo and his pledge of continuing support for lunar studies, the conferees adopted a motion that acknowledged some "awkward moments" over the years but praised the space agency for its overall execution of a project that had "already revolutionized ideas of the solar system's evolution." In a less formal but probably more meaningful gesture, a small group of the scientists who had been most intimately involved in planning the Apollo missions dug into their own pockets to honor selected NASA managers and engineers at a private banquet. One anonymous scientist said it was their way of saying thanks to "some of the higher people who played ball and to some of the lower echelon people - beautiful guys who would come along at the right time, stand up to their bosses, and help us get an experiment on board."12 It was a considerable change from the prevailing attitude only three and a half years before [see Chapter 10], but much else had changed in those years as well.
7. John Noble Wilford, "Expert Describes Lunar Cataclysm," New York Times, Mar. 6, 1973.
8. Robert Gillette and Allen L. Hammond, "Lunar Science: Letting Bygones be Bygones," Science 179 (1973): 1309; Noel W. Hinners, TWX to A. J. Calio, "Outline of Dr. Low's Talk for 4th Lunar Science Conference," Mar. 2, 1973.
9. Wilford, "Expert Describes Cataclysm"; Boyce Rensberger, "Moon Dead for 3 Billion Years, Experts Say," New York Times, Feb. 16, 1973; J. C. Huneke, E. K. Jessberger, F. A. Podosek, and G. J. Wasserburg, "40Ar/39Ar Measurements in Apollo 16 and 17 Samples and the Chronology of Metamorphic and Volcanic Activity in the Taurus-Littrow Region," Proceedings of the Fourth Lunar Science Conference (New York: Pergamon Press, 1973), pp. 1724-56.
10. Minutes, Lunar Sample Analysis Planning Team meeting.
11. Hammond, "Lunar Science: Analyzing the Apollo Legacy," Science 179 (1973):1313-15.
12. Gillette and Hammond, "Lunar Science: Letting Bygones be Bygones."