In recent years, space optical payloads have advanced toward higher spatial, temporal, radiometric, and spectral resolution, while becoming increasingly intelligent. The commercial remote sensing industry has made steady progress in expanding satellite systems and applications. Meanwhile, space optical remote sensing data has been widely applied to resource monitoring, meteorology, oceanography, environmental studies, disaster reduction, and many other fields.This proceedings volume contains selected and expanded contributions presented at the 2025 International Symposium on Space Optical Instruments and Applications, held in Dunhuang, China, on August 15–17, 2025. The symposium was organized by the Sino‑Holland Space Optical Instruments Joint Laboratory and supported by the Beijing Institute of Space Mechanics and Electricity.The symposium focused on key innovations in space‑based optical instruments and applications, highlighting the latest developments in theory, technology, and practice in both China and Europe. It provided a platform for academic exchange on current research and planned optical missions.The major topics covered in these proceedings include:1. Advanced optical technologies and new remote sensing techniques for space applications2. Optical material technologies and photoelectric conversion devices for space applications3. Space optics instruments and applications for deep space exploration and astronomical observation4. Space optics instruments and applications for ecological and environmental monitoring5. Commercial space optical remote sensing technologies and services6. Contributions of space remote sensing to the high‑quality development of the Belt and Road Initiative7. Integration of space remote sensing with artificial intelligence

In recent years, space optical payloads have advanced toward higher spatial, temporal, radiometric, and spectral resolution, while becoming increasingly intelligent. The commercial remote sensing industry has made steady progress in expanding satellite systems and applications. Meanwhile, space optical remote sensing data has been widely applied to resource monitoring, meteorology, oceanography, environmental studies, disaster reduction, and many other fields.This proceedings volume contains selected and expanded contributions presented at the 2025 International Symposium on Space Optical Instruments and Applications, held in Dunhuang, China, on August 15–17, 2025. The symposium was organized by the Sino‑Holland Space Optical Instruments Joint Laboratory and supported by the Beijing Institute of Space Mechanics and Electricity.The symposium focused on key innovations in space‑based optical instruments and applications, highlighting the latest developments in theory, technology, and practice in both China and Europe. It provided a platform for academic exchange on current research and planned optical missions.The major topics covered in these proceedings include:1. Advanced optical technologies and new remote sensing techniques for space applications2. Optical material technologies and photoelectric conversion devices for space applications3. Space optics instruments and applications for deep space exploration and astronomical observation4. Space optics instruments and applications for ecological and environmental monitoring5. Commercial space optical remote sensing technologies and services6. Contributions of space remote sensing to the high‑quality development of the Belt and Road Initiative7. Integration of space remote sensing with artificial intelligence

In recent years, space optical payloads have advanced toward higher spatial, temporal, radiometric, and spectral resolution, while becoming increasingly intelligent. The commercial remote sensing industry has made steady progress in expanding satellite systems and applications. Meanwhile, space optical remote sensing data has been widely applied to resource monitoring, meteorology, oceanography, environmental studies, disaster reduction, and many other fields.This proceedings volume contains selected and expanded contributions presented at the 2025 International Symposium on Space Optical Instruments and Applications, held in Dunhuang, China, on August 15–17, 2025. The symposium was organized by the Sino‑Holland Space Optical Instruments Joint Laboratory and supported by the Beijing Institute of Space Mechanics and Electricity.The symposium focused on key innovations in space‑based optical instruments and applications, highlighting the latest developments in theory, technology, and practice in both China and Europe. It provided a platform for academic exchange on current research and planned optical missions.The major topics covered in these proceedings include:1. Advanced optical technologies and new remote sensing techniques for space applications2. Optical material technologies and photoelectric conversion devices for space applications3. Space optics instruments and applications for deep space exploration and astronomical observation4. Space optics instruments and applications for ecological and environmental monitoring5. Commercial space optical remote sensing technologies and services6. Contributions of space remote sensing to the high‑quality development of the Belt and Road Initiative7. Integration of space remote sensing with artificial intelligence