If radio astronomers have their say, a replacement (unfortunately) will not be built. The fashion is to eschew 'single dish apertures' in favor of flat arrays that can be re-configured and self powered. We MUST self-power to be, oh, so, good to mother earth! Believe me, mother earth never had it as good as when people went from barbarians to technologists. I disagree with that 'green' approach as all inclusive, and I hold the patent on flat arrays that are self powered (see, for example, USP's 10483649 (especially claims 1,2, and 7); 10854987 issuing Dec 1. ) If someone champions 'aperture engines' as the way to go instead of singles dishes--a gross conclusion--they will find themselves not eligible for any form of license (particularly a 'free' one). I believe there are already people at Caltech trying to get money for that 'new' (hahah!) approach. Rude awakening ahead methinks. So how about that-- an inventor saying there is plenty of room, in this case , for classic and synthetic aperture optics. I fully support re-building AO as a single-science radio astronomical dish. Get rid of the add-on doo-dads that add cost and add weight!