Project A119 participant Carl Sagan
Project A119, also known as A Study of Lunar Research Flights, was a top-secret plan developed in 1958 by the United States Air Force. The aim of the project was to detonate a nuclear bomb on the Moon, which would help in answering some of the mysteries in planetary astronomy and astrogeology. If the explosive device detonated on the surface, and not in a lunar crater, the flash of explosive light would have been faintly visible to people on Earth with their naked eye. This was meant as a show of force resulting in a possible boosting of domestic morale in the capabilities of the United States, a boost that was needed after the Soviet Union took an early lead in the Space Race.
The project was never carried out, being cancelled after "Air Force officials decided its risks outweighed its benefits", and because a Moon landing would undoubtedly be a more popular achievement in the eyes of the American and international public alike. If executed, the plan might have led to a potential militarization of space. An identical project by the Soviet Union (Project E-4) also never came to fruition due to fears of the warhead falling back on Soviet territory, and the potential for an international incident.
The existence of the US project was revealed in 2000 by a former executive at the National Aeronautics and Space Administration (NASA), Leonard Reiffel, who had led the project in 1958. A young Carl Sagan was part of the team responsible for predicting the effects of a nuclear explosion in vacuum and low gravity, and evaluating the scientific value of the project. The relevant documents remained secret for nearly 45 years and, despite Reiffel's revelations, the United States government has never officially acknowledged its involvement in the study.Research
A ten-member team, led by Leonard Reiffel, was assembled at the Illinois Institute of Technology in Chicago to study the potential visibility of the explosion, the benefits to science, and the implications for the lunar surface. Among the members of the research team were astronomer Gerard Kuiper and his doctoral student Carl Sagan. Sagan was responsible for the mathematical projection of the expansion of a dust cloud in space around the Moon, an essential element in determining its visibility from Earth.Scientists initially considered using a hydrogen bomb for the project, but the United States Air Force vetoed that idea due to the weight of such a device, because it would be too heavy to be propelled by the missile which would have been used. It was then decided to use a W25 warhead, a small, lightweight warhead with a relatively low 1.7 kiloton yield. By contrast, the Little Boy bomb dropped on the Japanese city of Hiroshima in 1945 had a yield of 13–18 kilotons. The W25 would be carried by a rocket toward the shadowed side of the Moon where it would detonate on impact. The dust cloud resulting from the explosion would be lit by the Sun and therefore visible from Earth. According to Reiffel, the Air Force's progress in the development of intercontinental ballistic missiles would have made such a launch feasible by 1959.