October 26, 2006:
The U.S. Air Force wanted to retire its 33 U-2 reconnaissance aircraft, and replace them with UAVs like Global Hawk. But Congress refused to allow it, partly for political reasons (jobs would be lost, which is always a live political issue), and some in Congress (and the air force) did not believe that Global Hawk was ready to completely replace the U-2.
Ever resourceful, the air force has decided to make the most of it by turning the U-2s into UAVs. This is not cutting edge technology, the air force has been turning warplanes into UAVs for over half a century, mainly for use as target aircraft (usually for missile tests, which require very realistic targets if you want to be really sure the missile works.) Replacing the U-2 pilot with software and automated controls also solves several other problems. Since the U-2 only carries a single pilot, the aircraft cannot safely stay in the air as long as it could, because the pilot would be come too fatigued. Currently, the max endurance for a U-2 is twelve hours. But without a pilot, and all the gear required by a pilot, you could carry more fuel, and keep a U-2 UAV in the air for up to 18 hours. Moreover, the U-2 can fly higher than the Global Hawk, and carry more sensors. So, in theory, a U-2 UAV is superior to Global Hawk.
The key unanswered question is how much will it cost to develop the software for flying the U-2 remotely, and how long will it take. That issue will be clarified in the next year, along with cost comparisons between a U-2 UAV and new Global Hawks.