Kelden Amadiro is a Spacer in the novels The Robots of Dawn and Robots and Empire. He is the head of the Robotics Institute on Aurora. He is known for being extremely against the expansion of Earth to other planets, and in the end even tries to destroy the Earth by speeding up the rate of radiation in its crust. His memory of this is erased by R. Giskard Reventlov and R. Daneel Olivaw; however they allow Levular Mandamus to destroy the Earth because his motives were more beneficial for humanity and were therefore allowable by the Zeroth Law of Robotics: a slow increase in the rate of radiation would drive Earthpeople to the outer worlds, but a quick death, what Amadiro wanted, would kill the Earth with its population still on it.
Read more about this topic: List Of Isaac Asimov's Robot Series Characters