International Meridian Circle Program

The International Meridian Circle Program is a collaborative space-weather science initiative led by the National Space Science Center of the Chinese Academy of Sciences. Formally launched on 12 June 2025, it aims to coordinate ground-based and space-based observations of the Sun–Earth environment, develop data-driven models and improve understanding of disturbances affecting spaceflight, communications and navigation. Its planned monitoring chain follows the 120 degrees east–60 degrees west meridian circle and builds on Chinese Meridian Project infrastructure. The proposed research effort spans more than a solar cycle. Initial cooperation agreements identify SCOSTEP, Korea Polar Research Institute, Nigeria's NASRDA, King Mongkut's Institute of Technology Ladkrabang and Muni University among participants. Coordinated observations, scientific research and shared data are programme objectives; they do not imply that every planned facility is already operational.