Richard L. Gerwin, the American architect behind the hydrogen bomb who significantly influenced postwar defense policies, as well as advancements in space exploration and medicine, passed away on Tuesday at his residence in Scarsdale, New York.

His son Thomas confirmed the news of his passing.

At just 23, Dr. Gerwin became the mastermind behind the world’s first fusion bomb. He later served as a scientific advisor to several presidents, contributing to the development of Pentagon weaponry and satellite reconnaissance systems, while advocating for a balanced approach to Soviet-American nuclear policies during the Cold War, and promoting a verifiable agreement on nuclear arms control.

His mentor, Nobel laureate Enrico Fermi, referred to him as “the only true genius I’ve ever met,” yet Dr. Gerwin was not the sole creator of the hydrogen bomb. Hungarian physicist Edward Teller and Polish mathematician Stanislaw Ulam, who played pivotal roles in bomb theory, hold substantial claims to that title.

From 1951 to 1952, Dr. Gerwin served as an instructor at the University of Chicago and a consultant at the Los Alamos National Laboratory in New Mexico, where he designed a real bomb based on Teller-Ulam’s concept. The experimental device, named Ivy Mike, was tested at the Marshall Islands in the Western Pacific.

The device was designed not merely as an explosive but rather to demonstrate the fusion concept. Weighing in at 82 tons, it was aircraft-unfriendly and resembled a massive thermos. Soviet scientists, who did not conduct similar tests until 1955, referred to it intermittently as the installation of thermonuclear nuclei.

On November 1, 1952, at the Enewetak atoll, an extraordinary fusion of atoms unleashed a blinding flash of light and a fireball measuring two miles in diameter, generating a force 700 times that of the bomb that obliterated Hiroshima 100 miles away in 1945.

As the development of American thermonuclear weapons remained cloaked in secrecy, Dr. Gerwin’s involvement in the creation of the first hydrogen bomb remained largely unknown to the public for decades, aside from those within government defense circles and select intelligence agencies. He was commonly referred to as Dr. Terror, and it wasn’t until later that he received public acknowledgment.

“According to Gerwin’s design, this test was conducted almost precisely as intended,” Dr. Teller acknowledged in a 1981 statement, recognizing the crucial role played by the young prodigy. However, this late recognition barely permeated the public consciousness.

Compared to later nuclear weapons, Dr. Gerwin’s bomb was rudimentary. Still, its sheer power evoked the ancient Hindu texts of the Bhagavad Gita, harkening back to the first atomic bomb test in New Mexico in 1945 and the haunting response from its creator, J. Robert Oppenheimer.

To Dr. Gerwin, however, it meant little.

“I didn’t consider the construction of a hydrogen bomb to be the most pivotal achievement in the world, or even in my life at the time,” he reflected in a 1984 interview, addressing feelings of guilt. “I believe the world would be better off without hydrogen bombs.”

Transitioning to IBM

Although the first hydrogen bomb was crafted to his specifications, Dr. Gerwin was absent during its explosion at Enewetak. “I’ve never witnessed a nuclear detonation,” he mentioned in a 2018 interview. “I didn’t want to spend the time there.”

By 1952, following the success of the hydrogen bomb project, he found himself at a crossroads: he could return to the University of Chicago, where he had earned his PhD under Fermi and was now an assistant professor, or leverage a more flexible role at International Business Machines Corporation. This position provided faculty appointments at the Thomas J. Watson Institute at Columbia University, allowing greater freedom in his research interests while also permitting him to continue consulting for the government in Los Alamos and Washington.

He opted for IBM, where he remained for 40 years before retiring.

At IBM, Dr. Gerwin engaged in a continuous series of applied research projects leading to groundbreaking patents, scientific papers, and technological innovations in computing, communications, and medicine. His work was vital in the advancement of magnetic resonance imaging (MRI), high-speed laser printers, and subsequent touchscreen technologies.

An innovative maverick, Dr. Gerwin dedicated decades to exploring gravitational waves, as predicted by Einstein. In 2015, the costly detector he supported succeeded in detecting ripples, opening new frontiers in astrophysics.

Throughout this time, Dr. Gerwin also provided government consulting on national defense issues. With expertise in weapons of mass destruction, he aided in identifying Soviet targets and conducted research on various military aspects including nuclear submarines, military and civilian aircraft, as well as satellite reconnaissance and communications systems. Much of his work remained classified, keeping him largely unknown to the public.

He was a trusted advisor to numerous U.S. presidents including Dwight D. Eisenhower, John F. Kennedy, Lyndon B. Johnson, Richard M. Nixon, Jimmy Carter, and Bill Clinton. Notably, he was linked to President Ronald Reagan’s proposal for a space-based missile defense system dubbed Star Wars, aimed at safeguarding the nation from nuclear threats. However, the system was never realized.

One of Dr. Gerwin’s most notable controversies did not revolve around national security. In 1970, while on Nixon’s Scientific Advisory Committee, he opposed the administration’s support for the development of supersonic transport (SST) aircraft. He argued that SST would be prohibitively expensive, excessively noisy, and detrimental to both the environment and commercial airline operations, leading Congress to withdraw funding. The UK and France, however, pursued their own SST, the Concorde, but Dr. Gerwin’s predictions ultimately proved largely accurate, resulting in dwindling interest.

Conflict with the Military

Despite his modest appearance, Dr. Gerwin, with his slightly disheveled hair and gentle demeanor, became a legendary figure within the defense sector, crafting speeches and articles as well as testifying before lawmakers regarding what he described as the Pentagon’s misleading options.

Many of his disagreements with military bodies were long-standing and intense. These included disputes over the B-1 bomber, Trident nuclear submarines, the MX missile system, and the MX missile system—a network of mobile intercontinental ballistic missiles, notorious as one of history’s most lethal weaponry—all of which eventually formed part of America’s extensive arsenal.

Frustrated yet determined, Dr. Gerwin maintained his stance that America should uphold a strategic equilibrium with the Soviet Union and other nuclear powers. He argued against weapons policies that could jeopardize that balance, believing that Moscow cared more for the survival of its citizens than the loss of American lives.

Dr. Gerwin endorsed nuclear disarmament, including the 1979 Strategic Arms Limitation Treaty (SALT II), which was negotiated by President Carter and Soviet Premier Leonid Brezhnev. Nonetheless, he argued that mutually assured destruction remained essential for preserving peace.

In 2021, he joined 700 scientists and engineers, including 21 Nobel laureates, in an appeal to President Joseph R. Biden Jr. to commit that the United States would not initiate a nuclear strike in conflict. Their correspondence also advocated for the termination of the presidential authority to unilaterally order nuclear strikes, arguing that such limitations would safeguard against potential reckless decisions made by future presidents.

This notion was politically charged, and Biden did not follow through with such a commitment.

In a 1981 interview with Quest Magazine, Dr. Gerwin stated, “Nuclear weapons are consequential, and their power lies in the deterrent of massive destruction, which prevents nuclear confrontations.”

A Childhood with Curiosity

Richard Lawrence Gerwin was born on April 19, 1928, in Cleveland, Ohio, the elder of two sons to Robert and Leona (Schwartz) Gerwin. His father worked as an electronics instructor at a technical high school by day and at a film theater by night, while his mother was an attorney general. From a young age, Richard, affectionately known as Dick, exhibited remarkable intelligence and technical skills, having repaired household appliances by the age of five.

He and his brother Edward attended public schools in Cleveland. Dick graduated from Cleveland Heights High School in 1944 at the age of 16, and he obtained his Bachelor of Arts in Physics in 1947 from what is now known as Case Western Reserve University.

In 1947, he married Lois Levy, who passed away in 2018. He is survived by two sons, Thomas and Jeffrey, a daughter, Laura, and five grandchildren, along with one great-grandson.

Under the mentorship of Fermi, Dr. Gerwin earned his master’s degree in 1948 and his doctorate in 1949, achieving the highest score in the university’s history on doctoral exams. He joined the faculty, but under Fermi’s influence, he also spent his summers at Los Alamos Lab, where he made his mark on the hydrogen bomb project.

After retiring in 1993, Dr. Gerwin chaired the State Department’s Arms Management and Non-Proliferation Advisory Committee until 2001. He served on the committee in 1998 to evaluate the ballistic missile threats to the United States.

Dr. Gerwin’s home in Scarsdale was in close proximity to the IBM Watson Lab, which relocated from Columbia University to Yorktown Heights, Westchester County, in 1970.

He held faculty appointments at prestigious institutions such as Harvard, Cornell, and Columbia. Over his career, he secured 47 patents, authored over 500 research papers, and wrote significant books including “Nuclear Weapons and World Politics” (1977, co-authored with David C. Gompert and Michael Mandelbaum) and “Megawatts and Megatons: The Turning Points of the Nuclear Age” (2001, co-authored with Georges Charpak).

His life was chronicled in the biography “The True Genius: The Life and Work of Richard Gerwin, the Most Influential Scientist You’ve Never Heard Of” (2017) by Joel N. Sherkin.

Throughout his career, Dr. Gerwin was honored with numerous accolades, including the 2002 National Medal of Science, the highest award for scientific and engineering achievements in the U.S., presented by President George W. Bush, and the Presidential Medal of Freedom, awarded by President Barack Obama in 2016.

Obama praised him during a light-hearted introduction at the White House, stating, “He tinkered with his father’s film projector and never shied away from problems in need of solutions. From reconnaissance satellites to MRI, GPS technologies, and touchscreens—his fingerprints are everywhere. He even patented a shell washing machine.”

William J. Broad and Ash Wu contributed to this report.