Satellite Today has learned the launch of the last of the Lockheed Martin [LMT]-built GPS II-R series GPS satellite aboard a Delta 2 launch vehicle from Cape Canaveral Air Force Station in Florida will likely occur shortly after midnight tonight. The window for the launch will be open between 12:43 a.m. EST and 1:11 a.m. EST. If successful, this will be the 53^rd GPS satellite launched by the U.S. Air Force and the 30^th satellite in the current GPS constellation. The launch of this satellite has been delayed twice due to the hurricanes that swept through Florida earlier this year.