Jack Parsons

John W. Parsons (October 2, 1914 – June 17, 1952) was an American rocket engineer and rocket propulsion researcher, chemist, and Thelemite occultist. Associated with the California Institute of Technology (Caltech), Parsons was one of the principal founders of both the Jet Propulsion Laboratory (JPL) and the Aerojet Engineering Corporation. Parsons’s occult and libertarian writings were published posthumously, with Western esoteric and countercultural circles citing him as one of the most significant figures in propagating Thelema across North America. Although academic interest in his scientific career was negligible, historians came to recognize Parsons’s contributions to rocket engineering. For these innovations, his advocacy of space exploration and human spaceflight, and his role in founding JPL and Aerojet, Parsons is regarded as among the most important figures in the history of the U.S. space program. He was married to fellow occultist Marjorie Cameron from 1946 until his death.