PurposeThe researchers conducted a collective case study to investigate how families engaged in making activities related to aerospace engineering in six pop-up makerspace programs held in libraries and one museum. The purpose of this paper is to support families’ engagement in design tasks and engineering thinking, three types of discussion prompts were used during each workshop. The orienting design conjecture was that discussion prompts would allow parents to lead productive conversations to support engineering-making activities.Design/methodology/approachWithin a collective case study approach, 20 consented families (22 adults, 25 children) engaged in making practices related to making a lunar rover with a scientific instrument panel. Data included cases of families’ talk and actions, as documented through video (22 h) and photographs of their engineering designs. An interpretivist, qualitative video-based analysis was conducted by creating individual narrative accounts of each family (including transcript excerpts and images).FindingsParents used the question prompts in ways that were integral to supporting youths’ participation in the engineering activities. Children often did not answer the astronomer’s questions directly; instead, the parents revoiced the prompts before the children’s engagement. Family prompts supported reflecting upon prior experiences, defining the design problem and maintaining the activity flow.Originality/valueDesigning discussion prompts, within a broader project-based learning pedagogy, supports family engagement in engineering design practices in out-of-school pop-up makerspace settings. The work suggests that parents play a crucial role in engineering workshops for youths aged 5 to 10 years old by revoicing prompts to keep families’ design work and sensemaking talk (connecting prior and new ideas) flowing throughout a makerspace workshop.