In First-World-War Britain, women's ambition to perform noncombatant duties for the military faced considerable public opposition. Nevertheless, by late 1916 up to 10,000 members of the female volunteer corps were working for the army, laying the foundation for some 90,000 auxiliaries of the official Women's Services, who filled support positions in the armed forces in the second half of the war. This essay focuses on the public debate in which the volunteers overcame their critics to understand how they obtained sufficient popular consent for their martial work. I explain the process in terms of shifting hegemonic understandings of space. As critics' arguments in the debate indicate, the gender attribution of war participation was organized and represented spatially, assigning men to the warlike 'front' as warriors and women to the peaceful 'home' as civilians. To redefine the meaning of these gendered wartime spaces, women volunteers deployed rival spatial discourses and practices in their campaign for martial employment. The essay explores the progress of these competing definitions through feminist and spatial theories, including gender performativity, discursively constructed and constructive spaces, and heterotopias. I argue that the upheaval caused by the war in gender and spatial norms undermined absolute conceptualizations of space with dichotomous binary areas on which critics drew for their arguments and reinforced more recent, relative spatialities, including the cultural construction of militarized heterotopic sites in between and paralleling both 'home' and 'front' for soldiers in training or recovery. The volunteers' efforts to gain access to military employment both contributed to and were supported by this shift. Heterotopic sites offered ideal discursive locations for constructing the new gender role of auxiliary soldiering through the performance of martial training and work, and competing spatial definitions provided arguments through which they could justify their activities to both critics and supporters.