Building relationships and developing successful cooperation in human-robot teams has been an object of research for several years now, yet the studies of long-term relationships in such teams could still be considered sparse. The presented paper is based on a case study of the long-term relationship between a student construction team, AGH Space Systems, and their creation: Kalman, an autonomous rover designed for assisting a human astronaut. The research aimed to measure the level of trust towards the rover among the members of the team and to explore potential factors that could influence it. The adequacy of calling the rover a ‘social robot’, despite its lack of functionalities for social interactions, was also evaluated.Results showed the average level of trust was relatively similar among the team members. The only measured factor which showed a moderate, negative correlation with the subjects’ level of trust was the amount of sleep they had the previous night. Based on the conducted observations it was concluded Kalman can be considered a social robot, at least according to some definitions, due to the social context it operates in – the team’s willingness to consider it a partially conscious team member.