A B-52 Stratofortress takes off from Runway 22 during a Fischer-Tropsch test flight from Edwards Air Force Base, Calif., on Sept. 19. During the flight, two of the aircraft's eight engines ran on the natural gas-based Fischer-Tropsch fuel blend. The bombers are from the 5th Bomb Wing at Minot Air Force Base, N.D. (U.S. Air Force photo/Chad Bellay)