The Lunar Orbiter program

The Luna and Zond series of unmanned U.S.S.R. spacecraft were designed to investigate the moon and its vicinity. Sixteen Luna spacecraft and, six Zond spacecraft have obtained lunar data. These series have included flyby, lunar-orbiting, and soft-landing missions. A variety of experiments were carried out by these spacecraft including studies of magnetism, X-ray and gamma emissions, gravitational anomalies, and chemical composition. Soil samples, near- and farside photography (both color and black and white), and earth-cloud photography were also acquired. Luna 17 and 23, carried automatic roving vehicles (Lunokhod 1 and 2) that traversed portions of the lunar surface. Lunokhod 1 roamed in Mare Imbrium near Sinus Iridum, and Lunokhod 2 roamed in the Crater Le Monnier at the eastern edge of Mare Serenitatis. The Luna 16, 20, and 24 missions soft-landed on the lunar surface, scooped up lunar material, and returned these samples to earth. The photographic samples received are in the form of paper prints. Some publications containing photographs are described.