Serhii Koroliov

Serhii Koroliov, before he became the head engineer of the soviet space program, was sent to a GULAG in 1939 as part of the Great Purge, where he was imprisoned and tortured for 6 years. He was instrumental in sending Yuri Gagarin to space. The other rocket scientists he was arrested with were executed. His death in 1966 was related to injuries/illness caused by his time in the Gulag. It set back the Soviet space program enough that USA beat them to the moon.