Abstract: A space domain awareness (SDA) system includes several sensor spacecraft, some in Earth orbit and others in cislunar space. Each sensor spacecraft can include a sensor payload of an active optical sensor (e.g., a laser emitter and laser detector) and an SDA processor. The processor detects, tracks, and characterizes resident space objects (RSOs) using the output from the active optical sensor. In some embodiments, the sensor payload also includes a passive optical sensor, an electromagnetic sensor, and/or a plasma sensor; the SDA processor can use the outputs of these optional additional sensors to detect, track, and characterize RSOs as well. It is also contemplated that the SDA system can include a plurality of debris capture spacecraft, each of which includes a debris impact pad that includes a series of shield and stuffing layers that respectively increase in density along an intercept direction.