Australia's largest single space activity involves the Defence Signals Directorate (DSD) of the Department of Defence, and concerns the interception of satellite signals. DSD currently maintains satellite signals intelligence (SIGINT) facilities at Stanley Fort in Hong Kong and Shoal Bay near Darwin, and a third station is under construction at Kojarena, near Geraldton, Western Australia. A satellite facility for intelligence communications is also maintained at Watsonia Barracks, Victoria. This monograph describes these facilities and the satellites with which they are concerned. It concludes that DSD's expansion into satellite SIGINT operations requires oversight to ensure that there is no reduction in the overall effectiveness of the Directorate. This monograph also includes a Note on the proposed New Zealand satellite SIGINT facility at Waihopai, near Blenheim, and cooperation between this facility and the DSD operations.