This paper begins by highlighting the necessity of combining sociological and psychoanalytic approaches in the study of social movements, but acknowledges that psychobiographical studies of prominent movement leaders sit uneasily within the sociological tradition. The author attempts to illustrate that leader psychobiography can make a contribution to understanding social movements, however, provided it offers a way into understanding broader psychosocial issues within the movement. This is achieved through a psychobiographical portrait of Bruce Gagnon, a leader within the outer space protection movement. The author argues for the central importance of both paranoid-schizoid and depressive mechanisms throughout Gagnon’s activist career. These eventually came to underpin Gagnon’s commitment to protecting outer space as a Kleinian ‘good object’. The paper concludes by suggesting how Gagnon’s psychobiography might be instructive in attempts to understand the wider movement, utilising Erikson’s model for psychohistorical study as a framework.