I read an autobiographical book by Freeman Dyson where he discussed Project Orion. They did some initial tests with normal explosives. IIRC he ultimately came to feel that it was a terrible idea have a vehicle that spread radioactive "pollution" as it travelled, even though this would be in space.
I once had the good fortune to meet Freeman Dyson.
What was the name of his book? I remember reading it in about 1979. Where'd you meet him?
How tall is Freeman Dyson? On TV decades ago he looked tiny compared to Dick Cavett who is darn short himself.