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 bodies are moved by angelic spirits, which govern and move them. He maintained, instead, that "celestial bodies are moved by their own natural inclinations similar to weight". Just as heavy bodies are naturally moved by their own weight, which is an intrinsic active principle, so the celestial bodies are naturally moved by a similar intrinsic principle. Since the heavens are spherical, the only motion that could be natural to them is rotation. Kilwardby's idea had been earlier held by another Oxford scholar, John Blund (c. 1175–1248). In two slightly different discussions, John Buridan (c.1295–1358) suggested that when God created the