US deploys space sensors to track nuclear explosions frame by frame

The United States has completed deployment of its latest space-based nuclear detonation detection system, the IIIA series of the Global Burst Detection system, which is hosted on GPS satellites and has been monitoring nuclear explosions worldwide for over 60 years. These sensors detect electromagnetic pulses, X-rays, and optical flashes from nuclear detonations, enabling real-time determination of the explosion’s time, location, and yield. Developed jointly by Sandia National Laboratories and Los Alamos National Laboratory, the IIIA series underwent successful calibration and testing after its final launch in May 2025, marking a significant advancement in the US’s nuclear detection capabilities. Looking ahead, the US is preparing to field the next-generation IIIF series starting in 2027, featuring a new core instrument called the Spectral Imaging Geolocation Hyper-Temporal Sensor (SIGHTS). This advanced optical sensor can capture tens of thousands of frames per second at megapixel resolution, allowing for faster and more accurate identification of nuclear events while reducing false positives. The II