Abstract: Superconducting nanowire single-photon detector (SNSPD) is a high-performance single-photon detector that can be extended to the mid-to long-wave infrared range. It is highly suitable for astronomical observation missions with requirements of a wide observation range, weak signal detection, and low dark count rates. This article introduces optical response models of SNSPD, establishes a connection between SNSPD parameters and astronomical measures, and describes the development of SNSPD in the mid-to long-wave infrared band. It analyzes the research directions and difficulties from the perspectives of materials, fabrications, device structures, optical enhancement structures, and large array size. It discusses the feasibility of its applications in astronomical detection fields, such as Lidar and exoplanet spectral detection. Finally, it summarizes and looks forward to the development direction of mid-to long-wave SNSPD, highlighting the issues that still need to be resolved, such as further wavelength extension, infrared optical enhancement structures, and miniaturization. SNSPD has achieved saturated internal quantum efficiency at 29μm, but there is still a far way from realizing megapixel arrays and high-detection efficiency devices. With the advancement of micro-nano processing technology and refrigeration technology, it is accessible to achieve high-efficiency mid-to long-wave SNSPD array devices on satellites.

Key words: mid-to long-wave infrared, superconducting nanowire single-photon detector, habitable planets detection, astronomical observation