Book excerpt: Major issues have plagued the US military space community for years. Foremost among these issues is the relationship between air and space. At a recent airpower conference, military leaders from the western powers presented discussions of airpower and space issues with a pervasive underlying assumption: that the next logical step from the exploitation of airpower and space capabilities was the merging of the two environments toward the exploitation of "aerospace" power. The current distinction between air and space rests on the fiscal and technical inability to merge them an inability that is soon to be overcome. Conferees dismissed environmental distinctions between the two on the grounds that there is no absolute boundary between air and space In Paths of Heaven, the chapter titled Ascendant Realms: Characteristics of Air and Space Power," I examine this assumption from the perspective of 21 different military characteristics and conclude it to be invalid. The reasons extend well beyond an inability fiscally and technically to merge the two realms.