The attempted retrieval was to be the end of a test mission, part of an overall project dubbed Nitelite, that could break new ground from so high up in the sky. The Adler team is attempting to be the first — in the world, they say — to use high-altitude balloons to map the light pollution a city emits. The metropolis it has in mind, of course, is the one the planetarium calls home, Chicago, city of the big shoulders and the unceasing evening glow.