AMU Military

Lost Technology: A Weapon So Classified, Even the US Government Forgot it Existed

By Wes O’Donnell, Managing Editor of

On February 17, 2009, the United States Navy received its first refurbished nuclear warhead, the W76, after many long years and an extreme delay in the reconstruction.  This weapon sits atop the Trident II missiles that are carried on the Ohio-class submarine.  The delay in the refurbishing process occurred for a very interesting reason:  When the engineers opened up the original warheads back in 2000, they came across a substance that had been codenamed “Fogbank”.  The problem was that none of them knew how to replicate what they were looking at.


Fogbank originated back in the late 1970s in Oak Ridge, Tennessee at the Facility 9404-11 located on the grounds of the Y-12 complex.  This site became one of seven facilities that would make up America’s nuclear weapons complex.

There is not much known about Fogbank because of the high level of classification.  However, unclassified sources reveal that it was manufactured in the Tennessee facility between 1975 and 1989.  Shortly after 1989, the building went dormant and in 1993 it was finally set for decommission.

Recognizing that weaponry of this type have operational life spans, the government determined in 1996 that vast amounts of their nuclear arsenal would need to be either replaced, refurbished or removed from service.  Answering the governments call to action, the Department of Energy began a program to refurbish many old weapons that could effectively have their lives extended.  In 2000, the National Nuclear Security Administration, which is the branch of the Department of Energy that deals with nuclear weaponry, deemed that the W76 warheads be set to be refurbished which would extend their life in service until at least the year 2040.


It quickly became apparent that it would be difficult to refurbish “Fogbank” because the Government Accountability Office reported that they had “kept few records of the process when the material was made in the 1980s and almost all the staff with expertise on production had retired, died or left the agency”.  Once this came to light, the NNSA briefly considered terminating the plans to refurbish the weapon and create a substitute in its place, but ultimately decided if they had made it once they could make it again.  The GAO would later criticize the NNSA for their decision saying “assumptions such as ‘we did it before so we can do it again’ are often wrong”.

The refurbishment proved to be a very difficult task with many obstacles that would delay its progress.  New production facilities needed to be built, engineers struggled to duplicate a viable version of the substance used in the past and deadlines had to be repeatedly pushed back.  It was such a complicated process that the NNSA eventually caved and agreed to invest $23 million to find a replacement for Fogbank.

In 2007 a glimmer of hope emerged when engineers believed they had come up with an alternative process to create Fogbank, however, when tests were run, the materials failed.  Hoping to move things along faster, in September 2007 the NNSA increased the Fogbank project level to “Code Blue” status putting it as their highest priority for the agency.  Even with this push their efforts failed.


1 year and $69 million dollars later, NNSA was finally able to come up with a viable way to manufacture Fogbank.  It finally handed over its first refurbish warhead to the U.S. Navy seven months after that.  It took almost a decade to complete the task but they were eventually successful.  The NNSA likes to refer to this debacle as an example of “lost knowledge”.

So, what is Fogbank exactly?

On one hand, that question is very hard to answer seeing as it has been described in the following manner “The material is classified. Its composition is classified. Its use in the weapon is classified, and the process itself is classified”.  On the other hand, many scientists believe it is an aerogel which can be described as a highly rigid yet incredibly low-density material.  It has the appearance of fog or smoke but is solid like Styrofoam.  The substance most likely served as an “interstage” in the warhead which is a substance surrounding the fission and fusion portions of the weapon channeling energy from one to another.  Once the fission-stage is detonated then the aerogel becomes a superheated plasma, triggering the larger fusion-stage detonation.


The lesson is that knowledge can be lost. Sometimes this is perfectly reasonable:  No one knows how to kill and skin a mastodon anymore, for obvious reasons. And cultures frequently lose knowledge as they evolve past it–you’d be hard pressed to find anyone who could write a computer program on punch-cards today. But there is something worrisome about misplacing knowledge that is only a generation or two old. And this happens more often than you might think.

As the GAO report on Fogbank admonishes, “assumptions such as ‘we did it before so we can do it again’ are often wrong.” For a society that believes itself to be in a postindustrial information age, that’s a sobering thought.

Wes O'Donnell

Wes O’Donnell is an Army and Air Force veteran and writer covering military and tech topics. As a sought-after professional speaker, Wes has presented at U.S. Air Force Academy, Fortune 500 companies, and TEDx, covering trending topics from data visualization to leadership and veterans’ advocacy. As a filmmaker, he directed the award-winning short film, “Memorial Day.”

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