A "traditional" space elevator.
The tower does a similar job to the much-vaunted space elevator. But while the elevator envisages using ribbons woven from superstrong nanotubes - a material that is as yet non-existent - the tower would use materials that are already available. And should something go wrong with the tower, failure of a few modules would not cause the whole structure to collapse.
This idea appeals to me very much, so I'm all-but-certain that I'm overlooking some fatal flaw. Pros? Cons? Feel free to comment.
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