AU-LM is a silicon single-photon detector (SPD) designed for CubeSat and space-based quantum applications. It operates in the 300–1000 nm wavelength range and provides high photon detection efficiency in the visible and near-infrared spectrum. The detector features low dark count rates, adjustable dead time, and nanosecond-level timing jitter, supporting reliable photon detection in space environments. AU-LM is optimized for compact size, low power consumption, and stable operation, making it suitable for spaceborne quantum communication, entanglement experiments, and optical payloads.