UAVs are starting to replace spy satellites in the major espionage agencies. The CIA has long had its own fleet of Predator UAVs, and now the NGA (National Geospatial-Intelligence Agency, which analyses stuff, makes maps, and the like) and NRO (National Reconnaissance Office, which builds and operates spy satellites) want more UAVs as well. The sudden NRO enthusiasm for UAVs is driven partly by money problems. Congress is increasingly reluctant to provide billions for new satellites. For less than a tenth of what a space satellite costs, the NRO realized they could buy high flying UAVs (like Global Hawk), and equip them with satellite grade sensors. In this way, the NRO can get the coverage they need without the expense of a spy satellite. There's a more practical reason as well, UAVs can circle a location (being "persistent"), while satellites only come by each orbit. NGA can also get stuff from a UAV that they cannot get from the more expensive satellites. This does not mean there will be fewer satellites, for you still need them to check out countries you cannot fly UAVs over. But in places like Afghanistan and Iraq, UAVs are cheaper, and more useful, than satellites.