Overview

The Korolev Basin was an early target of Lunar Orbiter I. The basin is named after Sergei Korolev, the chief designer of the first Soviet intercontinental ballistic missile, the R-7. He also led the design of Sputnik I, the first artificial satellite of Earth. This series of exposures (see Figure 7.5) covers quite a large sample of the far side crust - about 40° in each dimension. An overview of the area is shown in Figure 7.1. As is typical for the highlands on both the near and far sides, the surface is fully battered by craters, one overlapping the other.

This basin is in the highest area of the Moon, a mound that rises about 5 km over the reference geoid (see Figure 7.2). It has been suggested that this mound is ejecta from the nearby South Pole-Aitken basin but although that basin had a contribution, it was a relatively minor one. The major source is, more likely, the proposed Near Side Megabasin, whose antipode is located in the southwest quadrant of the floor of Korolev. In this view, Korolev sits on top of the mound of ejecta from the Near Side Megabasin.

As with all basins, the shape of the original surface where it impacted has modified the Korolev Basin, which has been formed on the curved surface of a mound. This is an illustration of the principle of superposition. As a basin forms in response to an impact, it follows the shape of the target surface. This is obvious in the case of a flat, level target whose only shape parameter is its elevation. For a flat surface with a slope, it is also obvious that the final shape can be estimated by adding the slope to the shape of a typical impact basin. The same principle applies to a surface with curvature, so long as the angle that the slopes make with the horizontal is small. The impact explosion will likely follow the initial target surface and the basin shape will be superimposed on the original target.

Figure 7.3 shows a radial profile of the elevation of the Korolev Basin. The antipode mound has distorted it so that it does not look much like the general model of impact basin radial profiles (see Figure 13.4). The curved line represents an estimate of the shape of the mound prior to the Korolev impact. It has a maximum elevation of 5000 m above the reference geoid of the Clementine database.

After subtracting the quadratic curve from the measured elevation profile, the corrected radial profile is shown in Figure 7.4. Correcting for curvature makes a much better fit to the model of impact basins.

As can be seen, the Korolev Basin is like any other impact basin, once the curvature is removed. The target surface also had an average slope relative to the basin because the basin is a little to the northeast of the antipode. It is not necessary to correct for slope because the process of deriving the radial profile automatically removes it.

There is one internal ring within Korolev, which shows as a bump in Figure 7.4. It can also be seen in the mosaic of Figure 7.2. Also, the center of the floor of Korolev, within the inner ring, has been raised above the level that the model of Figure 13.4 predicts for a fresh basin. This may ( reflect the deposit of ejecta from the Hertzsprung Basin to the east.

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