Discovery and exploration of the Solar System Soviet "Lunokhod 1", which landed on the Moon in 1970. The first to visit another planet was Sojourner, which travelled 500 metres across the surface of Mars in 1997. The only manned rover to visit another world was NASA's Lunar rover, which traveled with Apollos 15, 16 and 17 between 1971 and 1972. Overview of some missions to the Solar System. See also the categories for missions to , , , and . Crewed exploration of the Solar System ended in 1972. The first human being to reach space (defined as an altitude of over 100 km) and to orbit
Planet Stories is the folk-tale, the hero-tale of our particular niche in history". Also arguing in support of "Planet Stories", science fiction critic John Clute has commented that "the content was far more sophisticated than the covers". Bradbury's work for "Planet Stories" included two of the stories that he later incorporated into "The Martian Chronicles", including "The Million Year Picnic"; only one other story in the series had appeared before this. He also collaborated on a story with Brackett, "Lorelei of the Red Mist", based on an idea of hers, which appeared in the Summer of 1946. His stories for "Planet" demonstrate