In support of the Canadian Space Plan, the R&D branch of the Department of National Defence initiated a technical study to identify satellite system options that would improve the national surveillance network. Space-based infrared and visible-light sensors and real and synthetic-aperture radar systems were considered. This report summarizes the findings of the study, starting with a general discussion of surveillance requirements and a description of the 'case-study' approach used to formulate a surveillance concept. Applicable technolgoy is described, with emphasis on concepts that address specific surveillance deficiencies. Current fiscal realities and the high cost of space technology are addressed in a discussion of near-term options using data from commercial satellites, accessed through an improved dissemination network.