March 17, 2011: After nearly a decade of negotiations, and some false starts, South Korea agreed to buy four U.S. RQ-4 Global Hawk UAVs. The first one will arrive in three years. This is another aftereffect of the two North Korean attacks on South Korean troops in the last year.

One big reason for the delays was sticker shock. While much was made of the basic cost of each Global Hawk ($21 million), a South Korea government report subsequently pointed out that the overall cost of each UAV could go as high as $131 million. Meanwhile, the much smaller Shadow 200 UAV (which the U.S. Army uses extensively to support brigade and division intelligence efforts) costs about $300,000 each, and can do most of what the South Koreans want the Global Hawk to do. But eventually the South Koreans realized that the Shadow 200 will not, in fact, give them the kind of information they want from North Korea.

This Global Hawk saga began nine years ago, when South Korea decided to upgrade its intelligence efforts against North Korea. South Korea already had some good HUMINT (contacts with North Koreans and people who visit North Korea), but wanted to get more visual and electronic information. Subsequently, over $400 million was spent on what became known as the Geumgang and Baekdu projects. That was largely wasted effort. The wrong equipment was bought, and the results were disappointing. Originally, the South Koreans wanted to use a high flying UAV, but none were available to suit their needs. So it was decided a manned aircraft would be a good substitute. Four Hawker 800XP aircraft were bought, for flying along the DMZ (Demilitarizd Zone) that separates north and south. But once all the sensors were installed, the aircraft could not fly high, or fast, enough. The cameras used, which were supposed to see 80 kilometers into North Korea, didn't, because the Hawker 800XPs were flying too low. The resolution of the cameras also turned out to be about a tenth of what was desired (able to identify objects about half a meter in diameter). The aircraft were not as reliable as expected. So instead of having one in the air 24/7, one was up about four hours a day. Other sensors placed along the border also have much lower performance than expected.

Turns out that the RQ-4 was just what South Korea needed. The RQ-4 is a long range UAV, that can reach any place in the world in 24 hours. South Korea doesn't need that capability, but as far back as 2008, an RQ-4A stayed in the air for 23 hours. Current models can stay in the air for up to 30 hours. The RQ-4 can intensely scan land and water surfaces, and is particularly useful for South Korea, which wants to know what is going on inside North Korea, as well as off its coast. The video and still images an RQ-4 generates are transmitted via satellite to the ground, and can easily be put onto an Internet connection. In effect, the RQ-4 is like having a photo-satellite overhead all the time.

The latest models have been able to fly 20 hour missions, land for four hours of refueling and maintenance, and be off for another twenty hours in the sky. The RQ-4 has been very reliable, with aircraft being ready for action 95 percent of the time. The U.S. Air Force has been buying them at the rate of five a year, at a cost of $65 million each.

The latest B version is larger (wingspan of 42.3 meters/131 feet, and 15.5 meters/48 feet long) than the A model, and can carry an additional two tons of equipment. To support that, there's a new generator that produces 150 percent more electrical power. The B version is a lot more reliable. Early A models tended to fail and crash at the rate of once every thousand flight hours, mostly because of design flaws.

The first three RQ-4Bs entered service in 2006. At 13 tons, the Global Hawk is the size of a commuter airliner (like the Embraer ERJ 145), but costs nearly twice as much. Global Hawk can be equipped with much more powerful, and expensive, sensors. These more the double the cost of the aircraft. These spy satellite quality sensors (especially AESA radar) are usually worth the expense, because they enable the UAV, flying at over 60,000 feet, to get a sharp picture of all the territory it can see from that altitude, and identify objects as small as 30 centimeters (one foot) in diameter.