Honoring the Life of John L. Tucker

Founding father of detonator science and Manhattan Project–era legend dies at 105.

November 18, 2024

John L. Tucker spent more than four decades serving the national defense mission, ensuring the quality, reliability, and safety of explosives and detonators at the Laboratory. He died on September 20, 2023, in Santa Fe, New Mexico. He was 105.

“John joined the Manhattan Project and made valuable contributions. Then he played a huge role in the Cold War detonator program. And make no mistake: detonators are of fundamental importance in a nuclear weapon, and they can be extremely challenging to perfect,” said Lab senior historian Alan Carr. “John was at the heart of it all. And on top of that, he was a wonderful person.”

Both before and after his retirement in 1982, Tucker served as a teacher and a mentor to subsequent generations of Lab scientists and technicians.

Artboard 2 — Ensign John L. Tucker in front of a Quonset hut on Tinian Island during his service in Project Alberta, which ensured an atomic bomb could be successfully dropped by aircraft, 1945. (Image courtesy of John L. Tucker’s family.)

Manhattan Project years, Tinian island

In 1942, fresh from the master’s in physics program at Louisiana State University, 24-year-old Tucker accepted a position as general foreman in a Charlotte, North Carolina, munitions plant supplying shells for U.S. Navy shipboard anti-aircraft guns.

“The munitions we were furnishing the military at that point in time were really sad . . . a lot of them didn’t work,” he recalled during a February 2014 interview.

Tucker was determined to change that. “Since I was in charge of quality and reliability of the 40-millimeter ammunition that we were making, I became kind of critical of a lot of things explosive,” he said.

Artboard 4 — A fireset identical to the one used to detonate the Fat Man bomb, on display at the Bradbury Science Museum in Los Alamos. The cover has been cross-sectioned to show the interior.

In 1945, as a commissioned officer in the Navy, Tucker joined the Manhattan Project—the top-secret, World War II government program in which the United States rushed to develop the world’s first atomic weapons before Nazi Germany did. He transferred to Los Alamos in March 1945, bringing his critical mind and commitment to quality to the race to build an atomic bomb.

During the Manhattan Project, Tucker designed, built, and tested detonators and bomb-handling equipment and wrote check sheets for detonator disassembly, inspection, testing, and reassembly.

In July 1945 he was sent to the Pacific island of Tinian to work on Project Alberta, which ensured an atomic bomb could be successfully dropped by aircraft. He personally tested and selected the fireset that armed Fat Man, the implosion bomb released over Nagasaki, Japan.

Artboard 5 — The housing for a detonator like the ones John Tucker worked with (right) next to a present-day detonator (left).

Tucker’s skill and experience were critical to Project Alberta in other ways as well. Prior to leaving Los Alamos for Tinian, he received permission to assemble a basic toolbox of implements that he thought he might need to perform his work in case the tools that had been shipped by boat never arrived. He arranged to have the backup supplies airlifted to Tinian by the “Green Hornet Line,” the nickname given to the squadron of planes providing essential air logistics support to the entire atomic mission. As he recalled in his interview decades later, “They were the only tools that we had to work with on Tinian. The tools that were originally sent were found and showed up after V-J Day.”

“For many at Los Alamos during the Manhattan Project, the successful Trinity test was the culmination of their work,” said Lab historian Ellen McGehee. “However, we should not forget the contributions of Lab personnel like John Tucker, who went to Tinian under wartime conditions to assist with the final assembly of Fat Man and Little Boy.”

On August 12, 1945, Tucker was commended for his exceptional service on Project Alberta.

Artboard 6 — Ensign John L. Tucker (right) with brothers Paul (middle) and David (left) at the Clinton Engineer Works (codenamed Site X during the Manhattan Project), now Oak Ridge National Laboratory, 1945. Paul and John both served at Site X in Oak Ridge, Tennessee, for a time, but neither knew that the other was there. The two brothers “discovered” each other one day while walking the muddy lanes of the facility. (Image courtesy of John L. Tucker’s family.)

Founding father of detonator science

Tucker’s contributions to the Lab did not end on Tinian Island. Returning to Los Alamos after the war, he led the development of the Lab’s Detonator Firing Site (now TA-40) and authored two major detonator science references, The Los Alamos Detonator Catalog and Los Alamos Detonator History, both still in use today.

He also taught three-day seminars (known as “Tucker Tech”) to new engineers. He remained active as a consultant for another decade after his official retirement in 1982.

Artboard 3 — Ensign John L. Tucker’s Project Y McKibbin card, now part of the National Security Research Center collections. McKibbin cards were used between 1943 and 1953 to document employees’ information. They were named after Dorothy McKibbin, who ran the Project Y office in Santa Fe and was often the first point of contact for new arrivals.

Tucker’s wife, Syrena Morris Tucker, also worked at the Lab, performing weapons diagnostics work from 1961 to the late 1970s as a nuclear plate technician in the Physics division under particle physicist Louis Rosen, one of the original Manhattan Project scientists.

Tucker’s last visit to the Lab was May 8, 2018—his 100th birthday—during the Lab’s 75th anniversary commemorations. He and members of his family attended the dedication ceremony for the John L. Tucker Conference Room in TA-22, home of Los Alamos Detonator Production.

“Tucker’s lifetime as a weaponeer in the service of the highest ideals is a legacy of inspiration to those of us who’ve come after him,” said Lab detonator researcher Daniel Preston. “His dedication to the craft and deep wells of commitment echo in the halls where we work. Since the Manhattan days and into the future, John’s legacy continues to have an impact on the U.S. nuclear weapons stockpile.”

Former explosives researcher Cary Skidmore called Tucker “a hero for the ‘ordinary man.’ He was not a Ph.D. scientist . . . [he] was a master’s degreed engineer . . . [who] cared about safe operations for his co-workers and safe nuclear weapons designs . . . [and] was involved in training the generations that followed him. He cared about leaving a legacy, footprints for others to follow.”