Defense News in Brief: Fifteen years young – Rubidium Fountains continue service to the Navy’s Master Clock

Source: United States Navy

WASHINGTON, D.C. – As of March 2026, the rubidium fountain clocks have met the benchmark of 15 years of continuous operation as part of the U.S. Naval Observatory’s Master Clock ensemble. Developed and built at the observatory, these clocks were originally brought online in 2011, and their integration as part of the Master Clock shortly after enabled the generation of a time-scale more precise than any other in the world, a standard that continues to be the case today.