For its first decade, the museum existed behind security clearances. Then in 1963, Robert Porton, the Laboratory's community relations director, pushed to add unclassified exhibits. Bradbury approved the transfer, and soon World War II-era documents, photographs, and scientific memorabilia went on public display alongside working models of unclassified research projects. The response was immediate: 14,000 visitors from 50 states and 40 countries came in the first year alone. By 1965, the museum had moved to larger quarters. Hands-on models donated by scientific groups and divisions within the Laboratory filled the expanding space, transforming a classified archive into something approaching a real public museum.

In 1970, the museum was renamed for Norris E. Bradbury, the Laboratory's second director who had led the institution from 1945 to 1970. Bradbury had shepherded Los Alamos through the transition from wartime crash program to permanent national laboratory, overseeing the development of thermonuclear weapons and the growth of the facility into a major research center. The museum bearing his name underwent a major renovation in 1981, replacing informal donated exhibits with professionally designed displays. Videotapes, videodisks, and interactive computer programs arrived. New artifacts included a Mark 12A warhead, models of Vela and Navistar verification and communication satellites, and an air-launched cruise missile.

By 1987, annual attendance had reached 80,000 and parking had become impossible. Laboratory officials began searching for a new home. In April 1993, the museum moved into its present location in the heart of downtown Los Alamos, a building designed by William Agnew and Associates and leased by the Laboratory from a private owner. The new space gave the museum room to grow into the institution it is today: approximately 40 interactive exhibits tracing the history of the Manhattan Project, highlighting current and historic defense research, and showcasing work in nuclear weapons stockpile stewardship and other fields.

The museum's exhibits span the full arc of Los Alamos history, from the secret wartime laboratory to cutting-edge modern research. The Manhattan Project galleries display declassified documents, photographs, and artifacts from the race to build the atomic bomb, including those full-size models of Little Boy and Fat Man. Leaflets dropped on Hiroshima warning of further attacks are displayed alongside the weapons that made those warnings real. More recent additions cover the history of supercomputers, the Los Alamos Neutron Science Center, contributions to the Mars Curiosity rover, nanotechnology, algae biofuels, and high explosives research. Admission remains free.

The Bradbury Science Museum sits at the center of a town that exists because of science. Los Alamos was a boys' ranch school before the Manhattan Project commandeered it in 1943. The scientists who came to build the bomb included multiple Nobel laureates: Edwin McMillan, Emilio Segre, Frederick Reines. J. Robert Oppenheimer directed the laboratory. After the war, many stayed. The town grew around the laboratory, and the museum became its public face, the place where the most consequential and controversial scientific work of the twentieth century meets the people it was done for. Standing before those bomb replicas, the weight of what happened here is inescapable.