Thor (rocket family)

The Thor rocket family is a series of intermediate-range ballistic missiles (IRBMs) and space launch vehicles that originated with the PGM-17 Thor IRBM developed by the United States Air Force in the late 1950s. Designed to deliver a nuclear warhead, the Thor missile was deployed to the United Kingdom as part of Project Emily.

Following its military deployment, the Thor became a versatile platform for space exploration and commercial satellite launches. It served as the basis for numerous subsequent rocket configurations and stages, playing a crucial role in early U.S. space programs.

Significant variants and derivatives of the Thor include:

• Thor-Able: An early configuration that added an Able upper stage for increased performance, used for launching satellites and deep space probes.
• Thor-Delta: A highly successful and long-lived variant that became the Delta rocket family. The Delta evolved through numerous versions and became a workhorse for launching communications satellites and scientific payloads.
• Thor-Agena: Utilized the Agena upper stage, enabling the launch of heavier payloads and facilitating more complex orbital maneuvers. This configuration was frequently used for reconnaissance satellites.
• Delta II: While significantly evolved from the original Thor, the Delta II maintained the Thor's 1.2 meter (4 ft) diameter tankage as a core feature. It was another highly reliable and extensively used launch vehicle.

The Thor family's legacy extends to modern launch vehicles, with some technologies and design principles influencing subsequent generations of rockets. Its adaptability and success in both military and civilian applications cemented its place as a significant contributor to the history of rocketry and space exploration. The Thor rocket family represents a pivotal transition from early ballistic missile technology to reliable and versatile space launch capabilities.