425 Project Military Reconnaissance Satellite Constellation

The 425 Project is South Korea's military space program that deployed a constellation of five reconnaissance satellites between December 2023 and November 2025. The constellation comprises one electro-optical/infrared (EO/IR) satellite and four synthetic aperture radar (SAR) satellites, providing high-resolution imagery regardless of weather or lighting conditions. The SAR satellites can detect objects as small as 1 meter.

Before the 425 Project, South Korea depended entirely on US intelligence-sharing for satellite imagery of North Korean military activities — a critical sovereignty gap given that the Korean Peninsula remains technically at war. The constellation enables independent, near-real-time monitoring of North Korean nuclear facilities, missile launch sites, and troop movements without requiring permission or coordination with foreign intelligence services.

Completion of the 425 Project makes South Korea one of very few nations with indigenous military SAR reconnaissance capability. The program was developed with Korean-designed SAR payloads though launched on SpaceX Falcon 9 rockets. It dramatically shifts the intelligence balance on the peninsula and provides a foundation for future military space capabilities including potential missile early-warning systems.