Luna programme became the first probe to achieve a soft landing on another planetary body. It returned five black and white stereoscopic circular panoramas, which were the first close-up shots of the Lunar surface. "Luna 10" (March 1966) became the first artificial satellite of the Moon. "Luna 17" (November 1970) and "Luna 21" (January 1973) carried the Lunokhod vehicles, which roamed around on the Moon's terrain. Another major achievement of the Luna programme, with "Luna 16" (September 1970), "Luna 20" (February 1972) and "Luna 24" (August 1976), was the ability to collect samples of lunar soil and return them to Earth. The
Dynamics of the celestial spheres Dynamics of the celestial spheres Ancient, medieval and Renaissance astronomers and philosophers developed many different theories about the dynamics of the celestial spheres. They explained the motions of the various nested spheres in terms of the materials of which they were made, external movers such as celestial intelligences, and internal movers such as motive souls or impressed forces. Most of these models were qualitative, although a few of them incorporated quantitative analyses that related speed, motive force and resistance. In considering the physics of the celestial spheres, scholars followed two different views about the material composition of the celestial spheres.