Comment Why does it have to be liquid? (Score 1) 196
It would seem a relatively simpler matter to stretch a thin mylar membrane over a frame, like a drum head, apply a partial vacuum to introduce the basic curvature and then control the surface with a combination of loudspeaker-like actuators, operating at frequencies designed to create standing waves of arbitrary shape according to the needs of an adaptive optics control system.
This would have the advantages: lightweight, easy to assemble, use of off-the-shelf speaker technology, very high response time, relatively low power requirements, etc.
What's not to like?