“If you just talked about the project, said you were going to propel a ship with nuclear bombs, the immediate reaction was that this was crazy.

Taylor recruited theoretical physicist and mathematician Freeman Dyson, who effectively joined to bolster the credibility of Orion. Taylor knew Ulam through collaborative work at Los Alamos and described some of their conversations on fissile explosives in a 1995 oral history interview. Soon after, Ted Taylor, America’s leading atomic bomb designer at the time (though staunchly against nuclear weapons), sold the idea of a nuclear propelled spacecraft to General Atomic (also jokingly referred to as “Generous Atomics” by some physicists due to their ample financial resources), and Project Orion began. More than a decade of work at Lo s Alamos National Laboratory resulted in a co-authored 1955 report (and several reports thereafter) titled “On A Method of Propulsion of Projectiles By Means of External Nuclear Explosions: Part I.” Ulam’s idea for a spacecraft propelled by thousands of nuclear bombs was taking shape.

Polish mathematician Stanislaw Ulam, who worked on the Manhattan Project, undertook preliminary calculations as early as 1946. Nuclear power, once regarded as “too cheap to meter,” is a well-known example of these efforts, but some saw another opportunity: space travel. At the end of World War II, after witnessing the catastrophic destruction possible from nuclear weapons, physicists actively sought peaceful applications of such nuclear capabilities.

Kerbal space program physics 101