The story of that effort, dubbed Project Orion, is detailed in the excellent book of the same name by Freeman’s son, George. Advocates for nuclear pulse propulsion are still disappointed that the project was cancelled before any prototypes were built. Others argue that when you think about what they were trying to do—put a gigantic nuclear arsenal in a box, hurl it high into the atmosphere, and bomb it repeatedly—it’s terrifying that it got as far as it did.
