Lunar Shape via the Apollo Laser Altimeter.

Data from the Apollo 15 and Apollo 16 laser altimeters reveal the first accurate elevation differences between distant features on both sides of the moon. The large far-side depression observed in the Apollo 15 data is not present in the Apollo 16 data. When the laser results are compared with elevations on maps from the Aeronautical Chart and Information Center, differences of 2 kilometers over a few hundred kilometers are detected in the Mare Nubium and Mare Tranquillitatis regions. The Apollo 16 data alone would put a 2-kilometer bulge toward the earth; however, the combined data are best fit by a sphere of radius 1737.7 kilometers. The offset of the center of gravity from the optical center is about 2 kilometers toward the earth and 1 kilometer eastward. The polar direction parameters are not well determined.

Lunar Gravity via Apollo 14 Doppler Radio Tracking.

Gravity measurements at high resolution were obtained over a 100-kilometer band from + 70 degrees to -70 degrees of longitude during the orbits of low periapsis altitude (approximately 16 kilometers). The line-of-sight accelerations are plotted on Aeronautical Chart and Information Center mercator charts (scale 1 : 1,000,000) as contours at 10-milligal intervals. Direct correlations between gravity variations and surface features are easily determined. Theophilus, Hipparchus, and Ptolemaeus are negative features, whereas Mare Nectaris is a large positive region. The acceleration profiles over Mare Nectaris are suggestive of a broad disk near the surface rather than a deeply buried spherical body. These data are in good agreement with the short arc of Apollo 12 lunar module descent data.

Lunar Gravity over Large Craters from Apollo 12 Tracking Data.

The Doppler residuals from the Apollo 12 lunar module radio tracking data indicate large negative accelerations over the craters Ptolemaeus and Albategnius. The mass deficienicies required to produce these accelerations are approximately equivalent to the removal of the surface material to a depth of 1 kilometer over the entire area of these craters. Several other features of the gravity fine structure can also be correlated with topography.