Widening participation in science is a long-held ambition of governments in the U.K. and elsewhere; however numbers of STEM entrants to university from low-socioeconomic status groups remain persistently low. The authors are conducting a long-term school-based space science intervention with a group of pupils from a very-low-participation area, and studied the science attitudes of the participants at the beginning of the programme. Key findings were that young people from the very-low-SES study cohort were just as interested in science study and science jobs as their peers nationally, and had a pre-existing interest in space science. Some participants, particularly boys, demonstrated a ‘concealed science identity’, in that they perceived themselves as a ‘science person’ but thought that other people did not. Boys tended to score higher on generalised ‘science identity’ measures, but the gender difference disappeared on more ‘realist’ measures. In addition, although participants agreed that it was useful to study science, they had little concrete idea as to why. These findings shed light on how science communicators can best address low-SES groups of young people with the aim of increasing their participation in science education and careers. We conclude that interventions with this group that focus on ‘aspiration raising’ are unlikely to be successful, and instead suggest that activities focus on how young people can see science as a realistic path for their future. It would be helpful for in-school programmes to allow young people an outlet to express their science identity, and to give information about the kinds of jobs that studying science may lead to. Further research into whether the gender split on idealist/realist measures of science identity persists over time would be of use.