North Korea's second attempt to place a spy satellite in orbit failed on Thursday after the rocket booster experienced a problem during its third stage, state media reported, as space authorities vowed to try again in October. Its first try in May also ended in failure when the new Chollima-1 rocket crashed into the sea. The pre-dawn launch came in the first hours of an eight-day window that North Korea had given for the attempt. The nuclear-armed country has been seeking to place what would be its first military spy satellite into orbit, saying it eventually plans a fleet of…