The Pentagon plans to spend $1 billion on the Global Hawk high-endurance high-altitude recon drone and position it to take over the U-2's role as the nation's primary spy plane. A series of upgrades are planned that will bring Global Hawk to a capability equivalent to the manned U-2. (The Pentagon wants to start retiring U-2s in 2007 and discard the last of them in 2011. But this cannot be done unless a new platform is available, and Global Hawk is the only realistic candidate.) Functional wing stations could carry additional payloads and sensors, such as synthetic aperture radar or signals interception antennae. The move will help Northrop Grumman, since the current program calls for the 6th and 7th prototypes to be delivered by 2002 but no production aircraft until 2005. The new Pentagon effort could see production aircraft moved up by a year or two. The primary roadblock to upgrading Global Hawk is that it is already using all of the available on-board electrical power. Increasing electrical power would require either a bigger engine or adding a separate generator. The improved version will have larger wings to carry the heavier loads. The Pentagon plans to have 40 Global Hawks flying in 2010 and 78 in 2020. These will include 48 with electro-optical systems (i.e., spy cameras) and the other 30 would be specialized for signals intelligence. There will be two aircraft for every payload set, since the sensor payloads are more expensive than the aircraft and the aircraft need maintenance between flights. (There are three U-2s for every sensor payload package.)-Stephen V Cole