Polish-American scientist of mathematics and nuclear physics.
Originated the Teller-Ulam thermonuclear weapon design, discovered the concept of cellular automation, and suggested nuclear pulse propulsion.
Ulam worked with Edward Teller on the Manhattan Project. He found that Teller’s “Super” bomb design was unworkable, so they co-created the Teller-Ulam Design, which is the basis for all thermonuclear weapons.
Stanislaw Ulam - Wikipedia
"Helping the US get the bomb, this Jewish mathematician faced an ethical problem" - The Times Of Israel (2021)