The surfaces of Phobos and Deimos

Knowledge acquired from spacecraft observations of the surfaces of Phobos and Deimos is reviewed. Consideration is given to: the first spacecraft data - Mariner 7; the first systematic exploration - Mariner 9; surface texture and composition from Mariner 9 data; surface morphology from Mariner 9; and Viking results. A series of Viking photographs of Phobos and Deimos is presented.