Although they work with two non-humanoid robots located several million miles away, the distributed team that operates the Mars Exploration Rovers demonstrates an uncanny sympathy for their robotic teammates. This paper examines how the Rovers are not only anthropomorphized by the human team, but how the team takes on characteristics of the Rovers while conducting science and operations on Mars. Based on two years of ethnographic fieldwork with the Mars Rover mission, the paper places the configuration of the user in social context and probes the role of the machine as social resource, with implications for HCI. Keywords Human-Robot Interaction, embodied computing, anthropomorphism, usability, affect, social robotics. ACM Classification Keywords H.5.m. Miscellaneous.