A lander mission to Europa 'Europa clipper mission' is planned to launch in the mid-2020s by NASA JPL. The mission presents multiple challenges, such as: ubiquitous presence of hazards at all scales, including craters, crevasses, boulders, etc.; ultra-high radiation environments due to proximity to Jupiter; and extremely limited lander resources for mass and volume and, hence, the amount of shielding that can be carried. Therefore, the critical phases of this mission require the ability to perform terrain-relative navigation (TRN) and surface-hazard detection in short time. To satisfy these requirements, a dual-functionality (altimetry and hazard mapping), large-format, monolithic, low-noise, highly sensitive, silicon single-photon avalanche photodiode (SPAD) lidar imager will be developed. The SPAD imager will be robust, radiation-hardened, and low in size, weight, and power, and it will provide altitude measurements to the ground beginning at an altitude of 8 km and all the way to touchdown (10 m altitude). At an altitude of 500 meters, it will provide a dense 3D terrain map covering a 100 m x 100 m landing area with 5 cm ground sample distance and range errors of less than 5 cm (3-sigma) in less than 1 second. The developed SPAD imager will be demonstrated in a benchtop lidar testbed.