The George Dyson video from 2002's TED just went live, describing the Orion Project, a deeply classified space vessel from the Atomic Age. It was nuclear powered. The size of a Marriott hotel and 400 tons. George Dyson's father worked on it, starting in General Atomic in 1957. Did I mention that scientists from the hydrogen bomb worked on this thing? Why? Because the nukes weren't used as fuel like they are at Homer Simpson's workplace. They were hoping to smash the atoms and direct the explosions for 20 megatons of lift!
Given the time frame, the planners on the Orion had even built in defence systems meant to retaliate against the Russians. This project was the first contract funded by DARPA. In this video, George also steps through passenger acceleration profiles, emergency plans if Orion failed to clear the atmosphere and the not so cool 700 rads of radiation you'd get while riding it. George's final take? If an asteroid headed for our planet, an Orion type ship is one of the only emergency plans that NASA could depend on, "off the shelf." And that's why NASA bought roughly 1700 pages of the notes he collected on Orion from him.