Institute for Telecommunication Sciences / January 1943

January 1943: First Radio Proximity Fuzed Ordinance Used in Combat

On January 5, 1943, the St. Louis Class light cruiser, USS Helena fired the first radio proximity fuzed ordinance in a combat action. The proximity fuze is considered to be one of the most important inventions to come out of World War II. Bombs that explode before impact cause greater damage than those that explode after impact, and reduce the effectiveness of foxholes and trenches. During the First World War, bombers realized this and attempted to bounce bombs off trees, cliffs, and other natural formations to trigger contact detonators. Soon timed fuzes were installed in ordinances, but these required perfect timing to explode in the proper position. Radio proximity fuzes held the promise of sensing their own altitude by reflecting radio waves off the ground and detonating at the proper time for maximum effect. Since 1940, the Navy and National Bureau of Standards had been working on parallel radio fuze projects. The Bureau's ordinance work was headed by Harry Diamond, and his Ordinance Development Division remained active until 1953, when it was transferred to the Army and renamed Diamond Ordinance Fuze Laboratories in honor of the NBS scientist. ITS researchers no longer develop ordinance, but they still work to keep members of the Armed Forces safe. Recent work includes improving tools for operational communications planning and developing propagation models for zero-height antennas—models that can help design systems to interfere with the signal intended to remotely detonate a buried improvised explosive device (IED).