By Scott Sullivan
“The iconic radar ball is a well-known community landmark visible for miles along the shore of Lake Michigan,” said Michigan deputy state historic preservation officer Martha MacFarlane-Faes.
“The groundbreaking technology it once employed was an important piece of our national defense infrastructure during the height of the Cold War,” she continued.
Located high atop the Mount Baldhead sand dune between downtown Saugatuck and Lake Michigan, the gap filler was byukt in 1957 to address the threat of an air attack of Soviet planes flying from the north over the North Pole during the 1950s and 1960s Cold War.
After World War II ended in 1945, the wartime allies United States and Soviet Union became adversaries in a quest for industrial, technological, and military superiority. Advancements in weapons, missiles and space technology came rapidly amid fear of an enemy attack.
Throughout the Cold War, the world was immersed in a sense of impending nuclear doom as both countries engaged each other through proxy wars and traded military and political feints. In the U.S., air raid siren tests, duck-and-cover drills and “we interrupt this program” announcements punctuated the waiting-in-dread anticipation of the rumble of Soviet nuclear bombers approaching over the northern horizon or the silent fall of a nuclear missile.
In North America, the potential for an air attack of Soviet planes was seen as a credible and constant threat. A continent-wide network of automated and manned radar installations which sought to identify, track and respond to airborne attackers was built. This system was controlled by the most capable real-time digital computers of its era and led the cutting-edge of digital processing, networking and communications.
But there was a weakness in the radar armor. High-power radar installations could “see” far into the skies, but could not identify potential aircraft flying at low altitude or near hilly terrain. These gaps in the system could present an opportunity for literal “under the radar” attack. Special “Gap Filler” radars were needed to scan the horizon in these specific areas.
The Saugatuck Gap Filler became operational in 1958 with a specific mission to search the skies over Lake Michigan where enemy planes might target Chicago or the steel mills of Indiana. The radar antenna atop the dune spun relentlessly, feeding data into vacuum tube storage equipment being transmitted continuously via telephone lines to the Custer Air Force Station near Battle Creek.
At the heart of this nationwide radar revolution was the first modem ever used in an actual application. Dozens of gap filler radars were built across the country to fill in the network scanning for attack. In 1963, the Saugatuck radar was upgraded with higher power radar equipment, representing refinements in the technology only a few years after it was built.
At this time, the radar antenna atop the tower was enclosed in the white globe-shaped “radome” made of fiberglass which is a beloved Saugatuck icon today.
By the late 1960s, threat of aircraft attack was quickly being overshadowed by the threat of intercontinental ballistic missiles, which fly too high and fast for gap filler radars to recognize. The Saugatuck installation was deactivated in 1968. The next year, the city of Saugatuck purchased the unused site near the top of the popular tourist steps to the summit of the dune.
The remains of this technology have sat in silence since this time, as other such radar stations across the country were torn down. Of 131 gap fillers built, Saugatuck’s is one of a handful, and the most technologically complete, which remains.
“The white radar ball is one of the most visible landmarks in Saugatuck and nearby Douglas,” said SHPO project coordinator and lead nomination reviewer Nathan Nietering, who as past Saugatuck-Douglas History Center executive director is familiar with the area.
“But the real significance is the technology used inside the ball and bunker building below,” Nietering continued. “The installation played a real role in protecting our nation, even though the Soviet air attack never came to be. The Cold War sped up the development of groundbreaking technology such as real-time computing, interactive graphics, modems and wide area networking, and the Saugatuck Gap Filler still embodies this period of history,” he said.
The National Register listing is an important step to documenting the history of the site and planning for a future use.
In 2021, Saugatuck City Council approved a resolution which established the Mt. Baldhead Radar Station Workgroup with the mission to protect, preserve and promote the radar station. Over the next 15 months, the group met its goal to stabilize the equipment building, secure the site and make it ready for future preservation activities.
“The group’s efforts,” said team and now council member Russ Gardner, “created interest in the community and, more importantly, began to increase people’s understanding of this asset’s history.
“Now, with the first phase of the project completed and with the recent National Register listing, it stands as an historical gem and the crown jewel of the city’s Mt. Baldhead Park.”
Avocational Cold War historian Chuck Gustafson led the research effort to nominate the local radar to the National Register.
“I have had a fascination with early electron tube, computer and radar technology for as long as I can remember,” said Gustafson. “The combination of those in the Saugatuck gap filler radar station is irresistible.
“The equipment is a rare snapshot of that period where emerging digital electronics had not quite left vacuum tube electronics behind. This is the only piece of the Cold War era Semi-Automatic Ground Environment (SAGE) air defense system in public hands that remains in place nearly as it was. To participate in nominating the Saugatuck radar to the National Register was the opportunity of a lifetime.”
To be considered for listing in the Register, a property must generally be at least 50 years old, and must also be significant when evaluated in relationship to major historical events or trends in the history of their community, the state or the nation. A property must also possess historic integrity – the ability to convey its significance.
More than 96,000 properties across the country, including nearly 2,000 in Michigan, have been listed in the National Register since the program began in the 1960s. The Register is a program of the National Park Service administered by the states.
Properties are nominated for listing by each state’s SHPO, often in partnership with local individuals or community organizations. For more information about how to nominate a property, visit michigan.gov/nrhp.
By Scott Sullivan