Jack Parsons

Lore & Background

Parsons was born in Los Angeles and raised in Pasadena, California. He began amateur rocket experiments with school friend Edward Forman in 1928. He attended Pasadena Junior College and later the University of Southern California but did not graduate. In 1936, Parsons, Forman, and Frank Malina formed the Caltech-affiliated Guggenheim Aeronautical Laboratory (GALCIT) Rocket Research Group, with support from Theodore von Kármán. The group worked on Jet-Assisted Take Off (JATO) for the U.S. military and founded Aerojet in 1942 to develop and sell JATO technology during World War II. The GALCIT Rocket Research Group became JPL in 1943.

In 1939, Parsons converted to Thelema, a religious movement founded by English occultist Aleister Crowley. He and his first wife, Helen Northrup, joined Crowley's Ordo Templi Orientis (O.T.O.), and he became the California O.T.O. branch leader in 1942. Historians of Western esotericism cite him as a prominent figure in propagating Thelema in North America. Parsons resigned from Aerojet in 1944 and was later dismissed from JPL, with the reasons being complex—including security concerns and his occult activities. In 1945, he and Helen divorced; in 1946, he married Marjorie Cameron. Shortly afterward, he had a falling out with L. Ron Hubbard over money and Cameron; while Hubbard was not legally convicted of fraud, the exact nature of the financial loss is debated by historians.

Parsons worked as an explosives expert during the late 1940s, but his career in rocketry ended due to accusations of espionage and the increasing trend of McCarthyism. He died at age 37 in a home laboratory explosion in 1952; his death was officially ruled an accident, but many associates suspected suicide or murder.

Reader's Guide

Jack Parsons is now recognized for his innovations in rocket engineering, advocacy of space exploration and human spaceflight, and as an important figure in the history of the U.S. space program. Although publicly unknown during his lifetime, his contributions to rocketry—particularly the invention of castable composite rocket propellant and his work on JATO—were foundational to the development of both JPL and Aerojet, institutions that remain central to aerospace research and industry. His involvement with Thelema and the O.T.O. marked him as a significant figure in Western esotericism, and his association with L. Ron Hubbard adds a notable chapter to the history of Scientology's early roots. The circumstances of his death remain disputed, with official records ruling it an accident while associates suspected suicide or murder. Parsons has been the subject of several biographies and fictionalized portrayals, reflecting his enduring fascination as a complex figure bridging science, occultism, and early space exploration.

Did You Know?

• Parsons invented the first rocket engine to use a castable, composite rocket propellant.
• He was one of the principal founders of both the Jet Propulsion Laboratory (JPL) and Aerojet.
• Parsons converted to Thelema in 1939 and became the California branch leader of the Ordo Templi Orientis in 1942.
• Parsons and L. Ron Hubbard had a falling out over money and a woman, but Hubbard was never legally convicted of fraud in the matter.