https://www.nasa.gov/mission/acs3
Authors. NASA
Venue. mission page (the agency on its own mission)
How the Institute flags it
established 3 times frontier 1 time
This source carries more than one flag across the corpus. That is not an inconsistency to resolve: the same work can be established evidence for one claim and frontier evidence for another, and the flag belongs to the use rather than to the source.