Arthur C Clarke proposed the idea in 1950 in a paper, and wrote a rather excellent short story about the concept (and a wild escape from a launch failure) calle

Arthur C Clarke proposed the idea in 1950 in a paper, and wrote a rather excellent short story about the concept (and a wild escape from a launch failure) called "Maelstrom II". In Clarke's story, the launch system is located on the Moon rather than Earth; the lower escape velocity and lack of atmosphere makes the fictional engineering a lot simpler (and allows the climax of the story, which I won't spoil).