EDWARDS AIR FORCE BASE, Calif. -- Two Northrop Grumman Global Hawk Advanced Concept Technology Demonstration aircraft were recently transferred from the U.S. Air Force to NASA's Dryden Flight Research Center here. Initial research activities beginning in 2009 will support NASA's Airborne Science Program. The ability of the unmanned Global Hawk aircraft to autonomously fly long distances and remain aloft for extended periods brings a new capability to the science community for measuring, monitoring and observing remote locations of the Earth. The two Global Hawks were the first and sixth aircraft built under the original development program sponsored by the Defense Advanced Research Projects Agency, and were made available to NASA when the Air Force had no further need for them. (NASA photo by Tony Landis)