The first mention of anything resembling a space station occurred in Edward Everett Hale’s 1869 “The Brick Moon”. The first to give serious, scientifically grounded consideration to space stations were Konstantin Tsiolkovsky and Hermann Oberth about two decades apart in the early 20th century. In 1929 Herman Potočnik’s The Problem of Space Travel was published, the first to envision a “rotating wheel” space station to create artificial gravity. Conceptualized during the Second World War, the “sun gun” was a theoretical orbital weapon orbiting Earth at a height of 8,200 kilometres (5,100 mi). No further research was ever conducted. In 1951, Wernher von Braun published a concept for a rotating wheel space station in Collier’s Weekly, referencing Potočnik’s idea. However, development of a rotating station was never begun in the 20th century.
But small moons like Methone are usually geologically inactive and bereft of an atmosphere. Therefore, they are usually unable to smooth away the scars. Dr. Peter Thomas of Cornell University in Ithaca, New York, explained it this way in the May 17, 2013 New Scientist: "When we look at objects less than 200 kilometers in radius, they are all like potatoes. They have lumps, grooves, craters." This makes Methone's smooth surface a mystery. Dr. Thomas is a Cassini team member. Titan's atmosphere is approximately 95% nitrogen. However, in a way that dramatically differs from Earth's own mostly-nitrogen atmosphere, Titan's atmosphere has very little oxygen. Indeed, the remainder of Titan's atmosphere is almost entirely composed of methane--along with small qunatities of other gases, such as ethane. At the extremely cold temperatures that are found at Saturn's great distance from the heat of our Star, Titan's methane and ethane can accumulate on its icy surface to form pools of liquid. "For the smallest craters that we're looking at, we think we're starting to see where the Moon has gone through so much fracturing that it gets to a point where the porosity of the crust just stays at some constant level. You can keep impacting it and you'll hit regions where you'll increase porosity here and decrease it there, but on average it stays constant," Dr. Soderblom continued to explain to the press on September 10, 2015.