Abstract: Since dominating the high ground has always been of considerable interest to warfighters, it follows that future warfare will be dominated by the ultimate high ground-space. The most significant problem plaguing terrestrial-based communications, surveillance and weapons systems is that they are often constrained to line-of-sight, which is limited to very short ranges, particularly when the land platform is at low heights. Space-based systems offer enormous potential as platforms for repeating communications, conducting surveillance and supporting navigation over vast areas compared to terrestrial-based systems. One of the difficulties with operations in space is the general lack throughout the world's defence forces of an agreed taxonomy. While doctrine (such as US Joint Publication JP 3-14 Joint Doctrine for Space Operations [1]) and agreed terms do exist for a number of areas of space operations, the taxonomies provided tend to be focussed on particular areas and defined around existing systems and applications. There is therefore a need for a comprehensive top-level approach to the description of the constituent elements of space operations. An important characteristic of this description is that it needs to take into account the impact of space on the providers of space services, as well as the users of these services, and the impact of space on other battlespace entities that are not direct users of space. This paper therefore proposes a taxonomy for military space operations.