Space is so important that the DOD recognizes it as one of five domains in which US forces operate (the other four are land, sea, air, and information). In 2001 Secretary of Defense Donald Rumsfeld designated the Department of the Air Force (DAF) the “Executive Agent for Space for the DOD.” Given the national importance of space activities, the formation of a separate space force has been a topic of persistent discussion in academic and doctrinal circles ever since the United States first entered the space age. Proponents of a separate force argue that because space is an inherently unique domain, forces operating there should be organized, trained, equipped, and funded separately—as are air, land, and sea forces. Opponents highlight the interconnectedness of space activities in the other domains as primary justification for maintaining the status quo.
Air & Space Power Journal
Stover, L. R., & Johnson, A. (2014). Space Separatism: Degree of Differentiation. Air & Space Power Journal, 28(6), 17-37.