While the RQ-4A Global Hawk UAV flew only four percent of the recon missions during the Iraq campaign, it located 55 percent of the time sensitive targets. This was because the Global Hawk is a large bird (weighing 12 tons), and carries many powerful sensors. For example, its 550 pound SAR (synthetic aperture radar) can see through sand storms and can identify objects as small as one meter (39 inches) in diameter. Since Global Hawk can circle over an area for hours, the SAR can systematically search a large area, and then zero in on likely targets (where the SAR can distinguish items a foot across.) The sensors on board can carefully search 1,900 two by two kilometer boxes a day, or sweep over 120,000 square kilometers a day by searching a ten kilometers wide path it flies over. The aircraft carries a ten inch telescope that can operate in the dark (sensing heat). The information collected is instantly sent out via a satellite link, which only requires twice the capacity (500 million bits) as the smaller and much less capable Predator (a telephone conversation takes up 2,000 bits.) At $35 million each, the Global Hawk is expensive. But in Iraq it was able to spot Iraqi armored divisions trying to move under cover of a sand storm. When a U.S. helicopter went down, it was Global Hawk that quickly found it. Some in the air force want to buy dozens of Global Hawks and cover future battlefields with these UAVs. This will give U.S. forces the ultimate "eye in the sky."