Operation Fitzwilliam


Operation Fitzwilliam was a highly classified US Air Force operation with the objective of developing methods for Long Range Detection of nuclear detonations. Conducted in conjunction with Operation Sandstone, the 1948 atomic tests at Eniwetok Atoll, it integrated airborne radioactive debris collection, seismic monitoring, and atmospheric acoustic wave detection to ensure that the U.S. could detect, track, and analyze nuclear detonations worldwide.

Origins

Following World War II the U.S. held a nuclear monopoly but military and intelligence officials warned that this advantage would not last. Rising tensions with the Soviet Union, along with evidence of espionage and scientific advancements, made it clear that nuclear proliferation was inevitable. Lewis L. Strauss, of the Atomic Energy Commission became concerned that the U.S. had no system in place for monitoring Soviet nuclear activity.
In September 1947, President Harry S. Truman initiated a directive instructing the U.S. military to develop a global system for detecting nuclear detonations. The directive was prompted by intelligence indicating that the Soviet Union was actively pursuing nuclear weapons development. In response, General Carl A. Spaatz, commanding general of the Air Forces, assigned Major General William E. Kepner, head of the Air Force Special Weapons Group and Deputy Commander of the newly formed Joint Task Force 7, to lead the effort in organizing Long-Range Detection.
With the necessity for a dedicated technical unit composed of experts in physics, meteorology, chemistry, geophysics, engineering, and military operations, General Kepner established AFMSW-1 on December 31, 1947. Major General Albert P. Hegenberger was appointed as the military commander, while Dr. Ellis Johnson was named technical director, overseeing the recruitment and assignment of scientists from research institutions, military laboratories, and classified programs. Personnel would be selected from key projects, including Project Mogul and radiochemical analysis teams with prior experience in Manhattan Project-era research.

Urgency and Planning Challenges

By early 1948, planning was already well underway for Operation Sandstone, the Atomic detonation tests scheduled to take place at Eniwetok Atoll in April and May 1948. Initially, no provisions had been made to incorporate nuclear detection experiments into Sandstone. It was not until January 1948 that General Kepner and his staff formally approved integrating a Long-Range Detection component into the tests. This late decision forced the newly formed AFMSW-1 to have to develop and deploy its detection capabilities in a compressed timeframe and with many technical and logistical hurdles.

1. Logistical and Deployment Issues

  • Operation Fitzwilliam required a vast network of airborne and ground-based stations, with aircraft operating from Hickam Field, Kwajalein, Guam, Alaska, California, and several other locations across the globe. Getting the necessary equipment, aircraft modifications, and trained personnel into place before the Sandstone tests proved to be a major undertaking.
  • Many of the stations were in remote locations, requiring long-range transport of specialized instruments, aircraft modifications, and radiochemical laboratories. Weather conditions and supply chain delays further complicated deployment.
  • The operation required radioactive sampling aircraft, but equipping B-29 bombers with airborne filter systems, modifying them for extended flights, and ensuring their availability for the mission required hurried last-minute adjustments.
  • Ground stations needed to be set up in time to capture nuclear debris from the explosions, but construction, equipment installation, and testing were so rushed that there was a concern about accuracy and data reliability.

    2. Scientific and Technical Limitations

  • The nuclear detection methods being used were still experimental. The technology for high-altitude air sampling, radiochemical analysis, and fallout tracking was in its early stages, with no prior large-scale field testing before the Sandstone detonations.
  • Aircraft contamination was a major concern. Planes flying through radioactive clouds risked being permanently contaminated, which would make repeated flights difficult and would require extensive decontamination procedures.
  • The airborne filtering systems used to collect radioactive particles were unreliable, with the possibility of filters becoming clogged or failing to capture sufficient samples.

    3. Coordination and Intelligence Gaps

  • The successful integration of Fitzwilliam into Sandstone necessitated close coordination among multiple agencies, including the U.S. Air Force, Army, Navy, Atomic Energy Commission, and intelligence services. Fitzwilliam's objectives had to be fully aligned with those of the Sandstone tests, ensuring no interference with ongoing operations. Achieving this required full cooperation between the leadership of Joint Task Force 7, responsible for Sandstone, and AFMSW-1 overseeing Fitzwilliam.
  • Communication failures between different branches slowed deployment. Conflicting security protocols, limited information-sharing, and classified restrictions made coordination difficult between military planners and scientists.
  • Personnel shortages were a problem, as only a small number of trained experts were available for nuclear detection. Rapid training programs were implemented, but many personnel arrived in the Pacific with minimal preparation for handling classified radiochemical materials or interpreting nuclear fallout data.
  • The urgency of the mission meant there was no opportunity for a proper full-scale rehearsal or pre-test calibration, forcing teams to rely on incomplete field testing and last-minute troubleshooting.

    Military Leadership and Execution

To address these challenges, Major General Hegenberger appointed Brigadier General Morris R. Nelson to oversee the integration of Fitzwilliam into the broader objectives of Sandsone and Col. Herbert W. Ehrgott was tasked with procurement and deployment of necessary equipment and resources for the operation. Both men were class of 1926 West Point classmates.
Col. Benjamin G. Holzman, an Air Force meteorologist and weather specialist, would contributing to both Operation Sandstone and Fitzwilliam, providing critical insights into the dispersion of nuclear debris in the upper atmosphere and coordinating global data collection at remote test sites. Holzman had previously contributed to Project Trinity and Operation Crossroads, where he helped develop meteorological tracking models.
In late January 1948, Col. Nelson P. Jackson of Joint Task Force 7 was assigned to AFMSW-1 to serve as the Operations Officer for Fitzwilliam. Reporting directly to General Kepner, he would facilitate the integration of Fitzwilliam into the existing operational and deployment framework of Sandstone. He was a former Commander of the 64th Fighter Wing during World War II, with experience in high-level military coordination. Additionally, he would be able to serve as the primary liaison between the two Operations and The Pentagon. Both Col. Alfred D. Starbird, the Deputy Chief of Staff for JTF-7, and Col. Milton F. Summerfelt, the Deputy Chief of Staff for Operations at the Atomic Energy Office were Jackson's classmates from the West Point Class of 1933.

Logistical Coordination

Col. Jackson departed Washington, D.C., on February 10, 1948, and arrived at Fort Shafter, Hawaii, on February 12. Upon arrival, he coordinated with key military units throughout February and early March 1948 to provide support for Operation Fitzwilliam:
  • Pacific Air Command – Would deploy aircraft for airborne nuclear debris collection.
  • U.S. Army Pacific & Hawaiian Air Materiel Area – Would assist in the placement of seismic monitoring stations.
  • Pacific Fleet – would provide naval security and operational support.
  • Army Security Agency – Would establish security and communication protocols.
  • 308th Reconnaissance Group – Would aid in meteorological tracking and balloon-based nuclear debris detection.

    Secure Coded Communication

On March 9, 1948, Lieutenant General John E. Hull, Commander of JTF-7, and Major General William E. Kepner, Deputy Commander of JTF-7, held a high-priority meeting with Col. Nelson P. Jackson, assigning him the task of establishing a secure coded messaging system to transmit the nuclear detonation countdowns and the test results without exposing classified data. Col. Jackson devised a system of dummy-coded messages and time signals to ensure secure and covert communication of sensitive information.

Operations Plan Deployment and Development (March 13–March 21, 1948)

  • March 13, 1948 – Col. Jackson and his team board the USS Mount McKinley, the flagship of JTF-7, departing for Eniwetok Atoll.
  • March 16, 1948 – They arrive at Eniwetok and begin setting up Fitzwilliam Forward, the operational hub.
  • March 17–18, 1948 – Col. Jackson conducts a command post exercise aboard the USS Mount McKinley, simulating real-world detection and response procedures.
  • March 21, 1948 – Col. Jackson finalized and published Operations Plan Serial No. 1-48, the official document governing Fitzwilliam operations.

    Scientific Involvement

With the decision in January 1948 to integrate long-range nuclear detection experiments into Operation Sandstone, Dr. Ellis Johnson, Technical Director of AFMSW-1, began assembling a team of top scientific experts. He coordinated with existing Air Force research units, university laboratories, and private research firms to leverage their expertise. All the science teams that made up Operation Fitzwilliam were members on contract from either , , Columbia University or New York University NYU.