LIDARs are considered a key enabling technology for an array of applications in space, including celestial body approach, landing, rendezvous and docking, space debris identification and CubeSat constellations. Reliability, low cost and low size, weight and power (SWaP) are critical factors for these applications. Current spaceborne LIDAR systems are based on discrete optical components. These systems consume a lot of power and are bulky. In this work, a hybrid integrated (FMCW) LIDAR system operating at 1550 nm and based on an indium phosphide (InP) and silicon nitride (Si3N4) platform along with an external erbium-doped fiber amplifier (EDFA) compact module is proposed. By using a telecom-wavelength laser with an ultra-narrow linewidth of 1 kHz, and a 1D optical phased array (OPA) using lead zirconate titanate (PZT) phase shifters, the proposed PIC microlidar can operate up to 100 km. In order to realize small beam divergence, a 1x100 linear array consisting of 4 mm Si3N4 dual-layer grating antennas with a coupling efficiency of up to 80% of the incident power is utilized.