Covers depicting the fictional comic book character Superman often employ space themes. The above artwork shows Superman tossing an enormous mass into orbit. Note that the artist suggests Superman is "left-handed." At any rate, the picture is a useful object lesson for study of space technology. The "city in space" includes an enclosed atmosphere for air breathing as well as a structure for living quarters of the inhabitants, five people. Science fiction authors write of "worlds in space," ecological systems launched into space for journeys to the stars. The fallacy of such inventions is the enormous cost of placing the mass of even a small world in orbit. It is estimated that the cost of putting one pound in low Earth orbit is between $5,000 and $10,000.