Big Science projects, which cost billions of dollars and revolve around expensive, large, and complex instruments, are increasingly common in research. These projects are embedded in local communities through their physical infrastructure and, ideally, through their economic contributions and societal outreach. In cases where local communities consider economic benefits or community engagement insufficient, resistance to Big Science is likely to emerge. Typically, however, opposition is short-lived. The story is different for kiaʻi (protectors), a group of Native Hawaiians that opposes construction of the Thirty Meter Telescope (TMT) on Mauna Kea, Hawaiʻi Island. They have sustained opposition to TMT for almost ten years. Drawing on social movement theory and literature on place attachment as well as insights from 16 interviews that I conducted with Native Hawaiians, local community members, policymakers, and astronomers, I investigate why kiaʻi were able to retain such momentum. I argue that five factors – all of which have a specific Hawaiian bend – were decisive for the resilience of opposition: strong commitment, multi-generational and leaderful grassroots organization, community-based resources, versatile tactics, as well as political opportunity.