From preliminary spectral analyses of the Hubble Space Telescope images , the eastern hemisphere appears to be have a highly reflective , heavily cratered `` highland '' terrain with old , dusty rocks , and craters probing into deeper plutonic layers of the crust . From preliminary spectral analyses of the Hubble Space Telescope images , the eastern hemisphere appears to be some kind of high albedo , heavily cratered `` highland '' terrain with aged regolith , and craters probing into deeper plutonic layers of the crust .