John S. Foster, Jr., or “Johnny” as he preferred to be called, was a study in dichotomies. Instrumental in transforming the state of warfare, he had little desire for war. While his competitive spirit drove him to seek out solutions deemed impossible, he was loath to take singular credit for those innovations. Foster died at age 102 in April 2025. Quotes from some of Foster’s speeches and interviews reveal this larger-than-life figure in his own words and demonstrate how his legacy lives on at Lawrence Livermore National Laboratory.
Protecting the Warfighter
“When you’re talking about timely information, particularly for those on the battlefield, and you need many satellites, we cannot afford the (costly) ones we have pursued. We need…much less costly ones. Yes, they will not do as much individually, but collectively they will do just what we need.” [1]
A consistent motivation for Foster was his desire to protect the soldier on the battlefield. As a sophomore at Harvard University, he volunteered his expertise in radar technology to the war effort in Europe. One out of three bomber crews of the 15th Air Force of the United States Army was shot down by German artillery, so Foster obtained a German radar set and figured out how it worked. He then came up with tactics the bomber crews could use to outsmart German radar and, as a 1963 article in Science Digest stated, “visited every bomber base in Italy, briefing bomber crews on enemy radar tactics and how to use the new (countermeasure) equipment.” [2] These efforts improved bomber survivability rates by 50 percent. Along with the success of his efforts, Foster observed a gap between the science laboratory and the battlefield and the value that science offered the military—concepts that would shape his career.
As the leader of the Hectaton group at the Lawrence Radiation Laboratory at Livermore (now Lawrence Livermore National Laboratory) in the 1950s, Foster focused the team’s efforts on designing small tactical weapons to discourage human-wave attacks that nearly destroyed the United States’ Eighth Army during the Korean war, a project in contrast with Los Alamos National Laboratory’s work on megaton-scale nuclear devices. This emphasis on ground troop success persisted throughout his career. As physicist and author Tom Ramos states, “Johnny was passionate for the fighting man. He was always working on nuclear artillery for the soldiers on the ground. Right to the end of his days, (while) everyone else was covering the bombs in the air, (Foster considered), ‘who’s protecting the guy in the foxhole?’” [3]
An Environment of Competence and Trust
“The creation of an environment that was conducive to productive efforts by teams of scientists and engineers. An informal management approach that was without walls and based on competence and trust.” [1]
Inspired by the methods of his mentor, Ernest O. Lawrence, Foster fully embraced Lawrence’s matrix management approach. Unlike other organizational structures, the matrix system assembles teams designed to tackle a specific problem. These teams consist of members of multiple scientific and engineering disciplines, with all contributions valued equally. The 1963 Science Digest article quoted Foster as saying, “We don’t have a formal system of channels or chains of command, but we’re strong on who is responsible for getting the job done.” [2]
Prior to the international ban on atmospheric nuclear weapons testing, Foster flew his entire team to the Eniwetok Atoll of the Marshall Islands to witness detonation tests for Operation Redwing. Although not standard practice, Foster believed that assembling the whole team at the test would impress upon members their individual importance to the collective mission. He believed that no single person could solve the complex problems facing the nation. Foster’s aversion to a hierarchy of credit even extended to the physical comforts afforded his status “rank” in the project when it came to accommodations at Eniwetok. He gave up his private room so he could stay with his team in a shared, eight-bed room. Foster firmly believed innovation came from the conversations held between team members spending time together.
Dealing with the Unfamiliar
“This Laboratory is a special thing. Dealing constantly with the unfamiliar. We have the sense of challenge, of excitement, expectation, but the agony, the worry, and the headache. And the day these vanish, and it becomes a quiet, peaceful place, the purpose of the Laboratory will have ended.” [4]
In the most positive depiction of the proverbial ship that never reaches a home port, Foster was determined to keep innovating. In a 1991 interview with Finn Aaserud for the Niels Bohr Library, Foster stated, “I pay no attention to history, to the wake I leave behind. I spend my time looking out ahead and seeing what I can do to get us there.” [5] George Miller, Lawrence Livermore National Laboratory director from 2006 to 2011, says, “He (Foster) wanted to look out into the technical future and explore the big ideas, never small incremental steps.” [6]
During the test detonations at Eniwetok, Foster brought his team together in a Quonset hut to brainstorm the design of an even smaller, more efficient weapon. Starting with a problem statement and a blackboard, the team sought to capitalize on the lessons learned from Operation Redwing. After lengthy brainstorming sessions on that beach, the team came up with a new weapon design—the model on which the modern nuclear stockpile is based to this day.
When it became clear that the second-strike capabilities of the United States were vulnerable to sneak attack, Livermore’s reputation for innovation made it the preferred candidate to design the necessary warhead for a submarine-based system. Although the technology did not yet exist, Foster was confident that, with the size and reliability improvements achieved with Operation Redwing and a promising new design, his B Division and A Division, led by fellow Livermore physicist Harold Brown, could get the job done.
Backing Up the Vision
“You can have the vision, but you must convince others on the strengths of your arguments.” [4]
In 1955, months before the Hectaton group was scheduled to test a new weapon design, the Laboratory’s leaders instituted a process called the “pre-mortem” to prevent another failed detonation, which would threaten the Laboratory’s survival. During the pre-mortem, project team leads would defend weapon designs before a panel of experts skeptical that the design would work.
While Foster initially saw this process as burdensome, the inherent benefits were hard to ignore. As Ramos says, “Johnny just had this thoroughness. He wasn’t afraid to do it all over again…until he got it just the way he was supposed to.” [3] The pre-mortem process aligned with Foster’s own approach to testing ideas. The 1963 Science Digest profile stated that Foster would often roam the Laboratory, “dropping in on this or that group or shop, questioning in his incisive but friendly manner, exuding enthusiasm and encouragement.” [2]
In B Division, Foster held weekly meetings, known informally as “the Inquisition” or “Johnny’s Friday Frolics,” during which physicists and engineers presented progress reports from the previous week. Design ideas were discussed and, if a member of the team brought up a potential problem, everyone present talked through the issues and discussed solutions. What once seemed challenging and even inconvenient to team members became an integral part of the overall design process.
Michael May, the Laboratory director from 1965 to 1971, recalled, “(Foster) had a great facility for picking you out of whatever pleasant refuge you had found for yourself and posing a question to you…that you could not overlook.” [7] Although the weekly meetings could be contentious, everyone who knew Foster understood his motivations. George Miller says, “(Foster) treated everyone with respect. He could be probing the depths of (technical) understanding, but it was never personal, never mean-spirited.” [6]
The Toughest and Longest-Range Gambles
“The Laboratory had these twin responsibilities. On the one hand, develop nuclear explosives to keep the peace. On the other hand, take on the toughest and longest-range gambles the country can see in the hopes that with this effort and dedication one might make a payoff.” [4]
After years of designing nuclear weapons small enough to be carried by one person, another problem presented itself to Foster: security. Former Laboratory Director Bruce Tarter (1994 to 2002) captured in his book, The American Lab, the moment that the seriousness of this issue was first impressed upon Foster, “while watching the ease with which a Sandia technician could access the workings of (a nuclear) device.” He could not ignore the risks associated with an accidental detonation or security breach. Foster’s group began working on a system that would secure nuclear weapons against all but those who possessed the appropriate keys. In March 1962, during a visit to the Laboratory by President John F. Kennedy, Foster demonstrated this “key,” which would come to be known as the Permissive Action Link (PAL) technology. [8]
Foster came to be recognized as one of the preeminent experts on nuclear weapons technology in the country. For years, the Laboratory’s B Division had provided analysis and interpretation of potential nuclear weapon activities independent of the United States to the Central Intelligence Agency. The American Lab referred to the formation of the Laboratory’s Z Division as “one of the most far-reaching of all of Johnny Foster’s new initiatives as Director.” [8] Foster stressed the importance of this relationship when he explained, “While we can’t predict the future, we must look for snippets of information and any evidence of trends towards trouble. That’s why Z Division was formed many years ago, and why it’s important that the Laboratory has this expansion of those activities to cover the concerns about proliferation.” [1]
Preserving the Peace
“There’s no reason to believe in the foreseeable future that the people on this Earth are going to stop being mean to each other. And so, there’s no reason to believe…this laboratory will be able to relax in its vigilance and its effort to develop the best that America can have in the way of nuclear explosives.” [4]
Foster was not a warmonger and had no desire for warfare. During the 1965 Lawrence Radiation Laboratory Summer Family Lecture Series, he spoke about the Laboratory’s core work against the threats to the nation at that time: “No one at the Laboratory wants to work on nuclear weapons. The people in this Laboratory wish that it (the threat) would all go away.” However, he held the soberingly realistic view that only by maintaining the most reliable and effective nuclear deterrent could the United States hope to preserve peace in the face of the more aggressive and secretive enemy.
Foster’s passion for the security of the United States never faltered, nor did his insistence that the Laboratory tackle the toughest challenges of the day. Yet, when reflecting on his legacy, Foster doesn’t mention his long list of accomplishments or the many awards named after him. For him, the greatest satisfaction came from an environment at the Laboratory that allowed him to push further than even he could imagine and turn ideas into possibilities. As Foster said of himself, “What gave me the most satisfaction was the freedom to do more than I was capable to do...where I felt I was the limitation.” [1]
—John Rachal
[1] Lawrence Livermore National Laboratory’s 70th Anniversary Celebration with the Livermore Lab Foundation. A Special Lab Director panel discussion moderated by Ronald Lehman II. September 8, 2022.
[2] Wilkes, D. M. “Meet Johnny Foster,” Science Digest, September 1963.
[3] Ramos, T. Interview, June 23, 2025.
[4] Lawrence Radiation Laboratory Summer Family Lecture Series. John Foster. LRL Today. 1965.
[5] AIP. Niels Bohr Library and Archives/Transcript. John S. Foster. August 7, 1991.
[6] Miller, G. Interview. June 24, 2025.
[7] Extraordinary Science, Extraordinary Leadership. Lawrence Berkeley National Laboratory 50th Anniversary. 2002.
[8] Tarter, C. Bruce. The American Lab: An Insider’s History of the Lawrence Livermore National Laboratory, Johns Hopkins University Press, 2018. ProQuest Ebook Central, https://ebookcentral.proquest.com/lib/llnl/detail.action?docID=5339531.
