The US House of Representatives voted to close the $5.7 billion Stanley R. Mickelsen Safeguard complex in North Dakota just one day after it opened on Oct. 1, 1975. Daily Galaxy reported that the massive concrete pyramid was designed for nuclear defense during the Cold War but quickly lost its purpose.
Located on the plains of North Dakota, the facility was built to protect Minuteman missile sites at Grand Forks Air Force Base from potential ballistic missile strikes. The project represented a major investment in American anti-missile defense, featuring advanced radar systems and fortified structures.
The site operated two primary radar systems, including a perimeter acquisition radar that tracked missiles approaching from the north and a missile site radar housed inside the pyramid command center. This radar network guided a defense system equipped with 30 long-range Spartan interceptor missiles and 16 high-speed Sprint interceptors.
Pyramid design and closure decision
The pyramid structure alone cost nearly $140 million at the time, making it one of the most expensive parts of the complex. Its unique shape was functional rather than decorative, built with thick concrete walls to support heavy radar equipment and withstand nuclear conflict.
Congress voted to shut down the facility after Strategic Arms Limitation Talks between the United States and the Soviet Union changed anti-missile defense policy. A 1972 treaty restricted defense sites in both nations, halting other planned Safeguard locations and leaving North Dakota as the only completed site.
After standing idle for decades with its military equipment removed, parts of the complex including the pyramid were purchased by the Cavalier County Job Development Authority in 2017. Local officials later announced plans with a developer specializing in cryptocurrency and green computing to convert the facility into a secure high-performance data center.
Soviet retaliatory defense system
Popular Mechanics previously reported on another Cold War development, the Soviet Perimeter system, also known as Dead Hand, which remains capable of causing catastrophic destruction. The semi-automatic mechanism was designed to launch a retaliatory nuclear strike against the United States even if Soviet leadership was completely eliminated, requiring initial manual activation as destruction neared.
