This paper presents a high-speed Near-infrared single-photon detector developed under the frame of the TeQuantS project (Technological development for space-based Quantum Source distribution, ESA ARTES C&G Programme). Based on a GHz-gated avalanche photodiode operating in Geiger mode, the detector offers compactness, Peltier-cooling capability, maintenance-free operation, and high-speed single photon detection performances. These high performances make it wellsuited for extremely low light-level detection applications, such as space-borne quantum communications, satellite laser ranging, orbiting space debris optical tracking, and long-range LIDAR. The paper details the system's architecture and performance metrics, covering quantum efficiency, dark count rate, time jitter, maximum count rate, temporal window width, and afterpulsing probability. Substantial enhancements are demonstrated when using pulsed light compared to freerunning or MHz-gated Single Photon Avalanche Diodes (SPADs).