Development and Prospect of Space Optical Radiation Metrology Technology

Space Optics refers to the technology of observing and studying the Earth and space using optical equipment in the upper atmosphere and outer space. With the advancement of space exploration and aerospace programs worldwide, the application of space optics technology is becoming increasingly widespread, placing new demands on the development of space optical radiation metrology. These demands are mainly reflected in the continuous broadening of the spectral range, expansion of optical radiation measurement ranges, increasingly stringent requirements for measurement uncertainty, and a growing need for new on-orbit calibration technologies. At the same time, the widespread application of emerging technologies such as computational imaging, synthetic aperture imaging, quantum optics, and space laser communication, along with the use of optical equipment in special space environments like near-space and ultra-low orbit, has further driven innovation in space optical radiation metrology. This study systematically reviews the current state of space optical radiation metrology both domestically and internationally, focusing on two aspects: optical radiation metrology under simulated space environments and on-orbit optical radiation calibration. It covers typical methods and devices used in the extreme ultraviolet, mid- to far-infrared, and solar reflection spectral ranges. The main development trends in space optical radiation metrology are analyzed, highlighting how improvements to the classic absolute cryogenic radiometer technology, combined with modern quantum optics methods, have significantly enhanced the accuracy of laboratory optical radiation metrology. Additionally, by transferring optical radiation metrology benchmarks directly into space for on-orbit calibration, it is expected to surpass the accuracy limits of traditional on-orbit optical radiation calibration. Considering the trends in space optical radiation metrology and China's specific context, this study outlines key technologies that need to be prioritized in China. These include expanding spectral ranges, broadening measurement coverage, improving accuracy, enhancing on-orbit calibration capabilities, and addressing challenges posed by new technologies and environments. The aim is to provide robust optical radiation metrology support for the development of China’s space exploration technology.