Clues about mystery payload emerge soon after launch

A mysterious spacecraft whose mission is cloaked in secrecy left Cape Canaveral atop the hard-to-miss roar of its Atlas 5 rocket and then revealed a major clue about itself while cruising above a satellite-tracking hobbyist a short time later. The 19-story booster blasted off at 5:35 p.m. EDT, the first moment of the day's launch opportunity that punctuated a trouble-free countdown. More

(Source: Space Flight Now - Sep 10)