Underground life: Drills, rocks and biological activity.

What is life? To answer this question within STS, we should be attentive to the practices that allow to ask it and the specific affordances of different answers. To do so, this paper follows the activities of the Iberian Pyritic Belt Subsurface Life detection project (IPBSL), a research project of the Centro de Astrobiologìa of Madrid University that is searching for subsurface life forms in the subsoil of the area of the Tinto River. Attending to the research practices of IPBSL, the paper explores the notion of life in the version enacted by astrobiologists digging for life. Searching for life, here, means searching for (traces of) biological activity. This notion unhinges life from its textbook definitions, bounded and rendered dogmatic by their own generalizations and their removal from practices. Simultaneously, it reminds us that life is never completely fluid and out of bounds. Rather, it is (inter)dependent on the specific affordances of situated materialities. This offers us the empirical grounds to take on Deleuzian agencement and, yet, to stress the importance of the boundedness of material enactments of life in practices. In this way, we are reminded that the question of what life is cannot be answered in a univocal and definitive way, but rather in multiple, empirical and situated ones.