Thor DM-18

PGM-17A Thor SM-75

Mission Profile

Thor DM-18 (PGM-17A Thor, also known as SM-75) was the original production version of the American Thor intermediate-range ballistic missile and the progenitor of one of the most successful rocket lineages in spaceflight history. Standing 19.8 meters tall and weighing 49,900 kg, it generated 667 kN of thrust from a single LR-79 engine and first flew in January 1957. Deployed in the United Kingdom as a nuclear-armed IRBM during the Cold War, the Thor served its strategic role briefly before being phased out in favor of submarine-launched ballistic missiles. Its more lasting legacy came as the first stage of the Thor-Delta and later Delta rocket family, which flew continuously for over six decades.