[bkloppenborg]

From a comparable project, Georgia State University's Center for High Angular Resolution Astronomy ([CHARA](https://en.wikipedia.org/wiki/CHARA_array)) interferometric array was constructed for about $15m in 1985. That facility has six one-meter telescopes. That would be about $45M in 2024 dollars.

While I cannot attest for the accuracy of the cost estimate, I can note that the BFT takes several approaches which I think will help control costs. In particular, they are leveraging a multitude of proven technologies, COTS components, and smaller telescopes.

[aragilar]

It's also going after bright targets (down to 8 mag). GRAVITY on the VLTI using the UTs (4 × 8.4m) gets down to 17 mag (https://www.eso.org/sci/facilities/paranal/instruments/gravi...).

[echoangle]

It wasn’t constructed in 1985, that’s when planning began. It was constructed from 1996 to 2003. At least that’s what your linked Wikipedia article says.