top of page

Now You Know, August 2023, Section 2 of 2

Project ELSIE

By Sara Gray, Technical Information Specialist, NSWCDD

The high-level security granted employees a small amount of authority on base. Only specifically-cleared employees were granted access to the building. Even the base captain was not allowed access. And when the Fire Chief came to inspect the building, he too was denied access and told that if the building caught fire, just let it burn. The authority wasn’t even restricted to physical access. One time, Wes Meyers, a civilian scientist in charge of the ELSIE project, was speeding from the Butler Hut to the test site (there was a temperature component to some of the tests), and a Marine chased him the whole way. Sharing the incident years later during an interview for the base’s 100th anniversary, Meyers recalled:

…he accused me of going 50 miles an hour, and I told him it was faster than that. It was 55.

It was as fast as the jeep would go. He said, “Well, I’m going to take you in.” I said, “You’re

going to go right over there and go in that building and stand there and not make another


Yeah, I’d love to see the officer’s face when you try that next time you get pulled over. But for the ELSIE project and Wes Meyers, rules and regulations stated that when a test was happening, the person in charge had complete authority to do what he considered necessary. And speed was necessary.

Perhaps another reason for the high security was the danger brought on by the materials used in the bombs. About the only difference between the final version of the weapon and the version tested at Dahlgren was that the Dahlgren tests used either normal or depleted uranium, primarily the U-238 isotope. Special health people were sent to the base from Los Alamos to monitor if there were any radiation hazards involved. If it were spilled, it spread readily and was very difficult to control. Once there was a spill (by a man from Los Alamos), and he had to go through a special cleansing process to get it off his hands. If P-239, plutonium, was spilled, it could spread across a table, down the legs, across the floor, and onto the ceiling. The group kept buckets of axle grease around to stop such an accident from getting worse. Such dangerous material meant that none of it could be lost, and everything had to be accounted for down to the fraction of a gram. On one occasion, a device was lost out into the water. They had to mark where it landed in the river and send in a team of divers to retrieve it.

Fun anecdote: when Dahlgren received a shipment of the uranium, the team would take some sailors with them to help load and unload the boxes of uranium. The boxes were only 8-inches square, about a foot high, but they weighed about 100 pounds. Sailors were always very surprised to try and pick up a little box that was so heavy!

The ultimate ELSIE design was a Mark 8. It was much lighter than the Mark 1 “Little Boy” at only 3,230 pounds (Little Boy was 9,000 pounds) and measured in at 9.7 feet long and 14 inches in diameter, half the diameter of Little Boy. Its yield was probably 20-50 kilotons. The light weight meant that it could be carried on naval attack aircraft, including the AD-4B Skyraider, the AJ-1 Savage, and the FJ-4B Fury. Operation Buster-Jangle in 1951 confirmed the ballistic tests at Dahlgren: the Mark 8 was a suitable subsurface weapon. It went into production in February of 1952. Forty bombs were in the stockpile before the Mark 8 was replaced by the Mark 11, later renumbered 91, in 1956. The Mark 91 was also tested at Dahlgren and remained in service until 1960.

Once the Mark 91 entered service, Dahlgren’s involvement in the atomic weapons development program ended. Overall, gun-assembly bombs were overtaken by guided missiles with nuclear warheads. Dahlgren moved on to other projects, and the jungle slowly took over the remnants of one of our small parts in atomic warfare.

About the Author

Sara Gray works for NSWC Dahlgren in the Technical Library & Research Center. She has undergraduate degrees in History and Historic Preservation and a master’s in Management.

A version of this article was previously published as an NSWCDD blog in October of 2017. Reused with permission.

44 views0 comments
bottom of page