Spectral imaging for the outer solar system: Missions, instruments and current challenges

Spectral imaging is a key technique for investigating the surface composition and geological properties of objects in the outer solar system. Over the past few decades, missions to explore these objects have been conducted. According to different types and scientific objectives, these missions can be broadly categorized into three phases: reconnaissance, detailed characterization, and habitability assessment. The technology development and performance characteristics of imaging spectrometers onboard these spacecraft are systematically reviewed. As the performance of spectral imaging payloads approaches its limits and deep-space missions venture ever closer to the edge of the Solar System, three key technical challenges have emerged: photon-limited conditions, constrained data downlink capability, and communication delays. To address these issues, solutions are discussed across three levels: data acquisition, data management, and mission execution. This framework provides valuable guidance for designing imaging spectrometers for future outer solar system missions.