Slope characteristics of Europa: Constraints for landers and radar Sounding

Abstract

Limited Galileo‐derived topographic mapping of four major terrain types on Europa provides slope characteristics useful for designing spacecraft instruments and for terrain comparisons. Topographic data are derived using stereo and photoclinometric analysis of Galileo images at resolutions of 10 to 200 m (with a few sites sampled at ∼500 m resolution). Similar data are also presented for dark and bright terrains on Ganymede as well as preliminary results for polar terrains on Enceladus. RMS slopes for ridged plains, matrix, and crater deposits on Europa are typically between 10 and 15° at 10–100 m length scales, significantly steeper overall than typical landing sites on Mars. Terrains on Ganymede may be even rougher. Smooth dilational bands on Europa, however, have RMS slopes of ∼5°, the shallowest slope statistics of any major terrain type on Europa. Aside from these areas almost no smooth areas larger than a few kilometers across occur on Europa.