https://arxiv.org/abs/2002.11871
Authors. Turyshev et al
Venue. arXiv 2002.11871 — NIAC Phase II final report
How the Institute flags it
frontier 2 times speculative 2 times
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.