FRACTURE-CRATER INTERACTION ON ASTEROID 433EROS

The NEAR-Shoemaker spacecraft orbited the asteroid 433Eros for a period of one year in 2000-2001, acquiring many tens of thousands of high-resolution images and topographic profiles. We use a combination of NEAR Laser Rangefinder (NLR) data and NEAR Multi-Spectral Imager (MSI) images to characterize the interaction of fractures occurring within or adjacent to craters on the surface of the asteroid. Areas were selected for analysis in which both craters and fractures were present in one or more MSI images. Consecutive images of such areas were mosaicked and the corresponding NLR data was fitted to features of interest.

By combining topographic data with images, the effects of fractures on crater morphology and morphometry on an asteroid can be characterized for the first time. We find some areas of Eros exhibit a large number of densely-spaced lineaments which have clearly affected the shape of craters which they intersect, resulting in some which are significantly squared-off in planform. Effects of fractures on the depth:diameter ratios of craters are also recognized, an observation which may have implications for the surface properties and for the degree of crater retention on the asteroid. Fracture-crater interaction has likely played a significant role on the geologic history of 433Eros and probably other small bodies.