PASADENA, June 16 -- Somewhere in the sky tonight, a burst of radio energy will flare for a thousandth of a second and vanish, the death cry of something astronomers still do not fully understand. Almost all of these flashes go unseen, because no telescope can watch the whole sky fast enough to catch them. Caltech is about to build one that can. The university has cleared the final design review for the Deep Synoptic Array, a sprawling field of radio dishes in the Nevada desert built to survey the heavens faster than anything ever has, and the milestone clears the way for construction to begin, the university said.

The array will not look like the single great white dish most people picture when they imagine a radio telescope. It will be...