A method for orbital collision screening comprising, obtaining trajectory information of a plurality of objects moving on predictable paths. For each one of the plurality of objects, based upon respective trajectory information of the one of the plurality of objects, computing, a respective spatial descriptor of the path of the one of the plurality of objects, and storing the respective spatial descriptors of each of the plurality of objects in a data structure. Subsequently obtaining trajectory information of a further object, and based upon the trajectory information of the further object, computing a spatial descriptor of the path of the further object. Making first comparisons of the spatial descriptor of the further object against the respective spatial descriptors of each of the plurality of objects stored in the data structure to determine whether each of these first comparisons indicates a possible collision risk. Based upon each of the first comparisons, if the first comparison indicates a possible collision risk, determining a result of a close approach determination between the respective trajectory information of the respective one of the plurality of objects and the trajectory information of the further object, and taking an action based on result of the close approach determination satisfying a predetermined threshold.