The surface of the moon is covered with regolith, a layer of very specific loose highly heterogeneous material. On slopes, the regolith surface usually has a characteristic texture dubbed elephant…

This is a $228,380.00 grant awarded by the National Aeronautics and Space Administration (NASA) to the University of California, Santa Cruz (UCSC) to characterize the "elephant hide" texture observed on the lunar surface. The research aims to quantify the distribution, morphology, and potential formation mechanisms of this ubiquitous but poorly understood lunar surface feature. The project involves four technical tasks: bulk image analysis, high-resolution digital terrain modeling, qualitative morphological observations, and hypothesis formulation and testing. UCSC, as a public research university within the University of California system, frequently supports federal agencies like NASA through research and development contracts and grants. This award does not have a set-aside designation, reflecting UCSC's status as a large, highly capable research institution. The parent organization is the State of California Controller's Office, which has also participated in various federal contracting and grant activities.

The surface of the moon is covered with regolith, a layer of very specific loose highly heterogeneous material. On slopes, the regolith surface usually has a characteristic texture dubbed elephant hide or lathery texture . Its visibility and apparent anisotropy strongly depend on illumination/observation geometry, which makes IT elusive and difficult to study systematically. Although the elephant hide is ubiquitous and has been known for over half a century, IT still has not been characterized quantitatively. The mechanism of the elephant hide formation remains essentially unknown. The objective of this project is to characterize the elephant hide texture quantitatively and use this characterization as a basis for formulation and testing hypotheses of its formation. In particular, the following specific phenomenological questions will be addressed: whether elephant hide is globally uniform or its occurrence is regional? Does its occurrence correlate with latitude or slope orientation? Is there an onset slope for elephant hide formation? Are there characteristic scale lengths of the texture if yes, how do they depend on latitude, slope, its orientation? Does topographic amplitude of the texture correlate with latitude, slope, its orientation? Is the texture topographic amplitude well defined or varies significantly from place to place? Is elephant hide isotropic? If not, how does its orientation correlates with the downhill direction and local azimuth? Is there an albedo pattern associated with the texture? What are morphological relationships between elephant hide and partially degraded small craters in the regolith? The project objectives will be addressed through four technical tasks. Under task 1 bulk analysis of randomly selected image samples will be used to address the questions about elephant hide distribution. Under task 2 high-resolution digital terrain models will be created with the improved photoclinometry technique for randomly selected small samples of the texture they will be used to address the questions related to the texture morphometry. Under task 3 elephant hide peculiarities will be documented through qualitative morphological observations. Task 4 will be focused on synthesis, that is formulation and testing hypotheses of elephant hide origin.