Publications

The lunar maria formed at different times and in multiple stages of extrusion. An understanding of their evolution is essential in placing the Apollo samples in a regional context and in interpreting the regional geology of a vast part of the lunar surface.

A dark-colored surficial deposit covers lowlands and highlands along the southeastern margin of the Serenitatis basin. Sampling of this material was a major exploration objective of the Apollo 17 mission. Since completion of the mission, the dark mantle has been the subject of considerable controversy, inasmuch as no obvious stratified deposit was found in the landing area. Yet the...

The Apollo 17 lunar module (LM) landed on the flat floor of a deep valley that embays the mountainous highlands at the eastern rim of the Serenitatis basin. Serenitatis, the site of a pronounced mascon, is one of the major multi-ringed basins on the near side of the Moon. The Taurus-Littrow valley, which is radial to the Serenitatis basis, is interpreted as a deep graben formed by...

The scientific objectives of the Apollo lunar sounder experiment (ALSE) are (1) mapping of subsurface electrical conductivity structure to infer geological structure, (2) surface profiling to determine lunar topographic variations, (3) surface imaging, and (4) measuring galactic electromagnetic radiation in the lunar environment. The ALSE was a three-frequency, wide-band, coherent radar...

The lunar surface orientations of some of the Apollo 17 rock samples at the time of their collection (table 6-V) are shown in this appendix (figs. 6-65 to 6-87). These orientations were determined by correlating lunar photographs of samples before collection with shapes and shadow characteristics of the same samples in the LRL under oblique illumination with nearly collimated light. The...

The metric and panoramic cameras aboard the Apollo 16 spacecraft provided photographs on which photogrammetric techniques may be used to obtain precise measurements of horizontal distances and elevations. These measurements of horizontal distances and elevations. These measurements may in turn be used to obtain slope-frequency distributions of lunar surfaces at various slope lengths and...

Low-relief mare features such as ridges and arches are best studied by using stereoscopic photographs taken at low Sun angles. Apollo 16 metric camera photography of the southern Oceanus Procellarum east of Letronne Crater reveals a diversity of subtle features (fig. 29-125) and adds significantly to an understanding of the forms of mare ridges and arches their relative ages, and their...

Orbital and surface photography collected during the Apollo 16 mission can be used to calibrate existing Earth-based, high-resolution radar maps of the lunar surface. The absence of any theoretical treatment of the radar backscatter from irregular rocks has prevented the assignment of radar-echo cross sections to specific size distributions of rocks. This gap will now be filled with the...

The Apollo 16 crew photographed an unusual variety of impact craters, including the two craters produced by the impacts of Ranger 7 and 9 spacecraft, small craters produced by boulders as they bounced downslope, craters with marked bilateral symmetry, and primary craters with a wide range of morphologies and sizes. Ranger impact craters and examples of other craters are discussed briefly...

Apollo 16 metric photographs taken at low to high Sun angles (from approximately 7° to 40°) provide the first stereographic coverage of the distinctive landforms collectively referred to as "Imbrium sculpture" (refs. 29-40 and 29-41). The sculpture consists of a series of nearly linear ridges and troughs extending radially outward for more than 1000 km from the rim of the Imbrium Basin...

Geologic units of the Nectaris Basin rim have been interpreted as partly impact and partly volcanic in origin (refs. 29-4, 29-21, 29-35, 29-38, and 29-39). An exclusively volcanic origin was proposed for the material in the vicinity of the Apollo 16 landing site, slightly northwest of the Nectaris Basin (ref. 29-36). In view of the dominance of breccia and the paucity of volcanic...

More than four-fifths of the surface of the Moon consists of a profoundly cratered irregular surface designated terra or highlands by analogy with the terrestrial continents. These terra regions have much higher albedos than the physiographically lower and much smoother mare regions. The difference in albedo can now be ascribed to a fundamental difference in the chemical and...