Space: April 11, 2002

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During the 1990s, the U.S. armed forces moved to use satellite communications in a big way. This made sense for military communications, where troops often have to set up shop in out of the way places and need a reliable way to keep in touch with nearby forces on land and sea as well as bases and headquarters back in the United States. At the time of the 1991 Gulf War, there was enough satellite military communications capacity (commonly known as "bandwidth") in the Persian Gulf for about 1300 simultaneous phone calls. Or, as the geeks put it, 100 mega (million) bits per second. But while the military has a lot more satellite capacity now (the exact amount is a secret), demand has increased even faster. UAV reconnaissance aircraft use enormous amounts of satellite capacity. The Global Hawk needed 500 megabits, and Predators about half as much. The major consumer of bandwidth is the live video. UAVs have other sensors as well, as do aircraft. A voice radio connection only takes about 2,000 bits per second, and each of the multiple channels needed to control the UAVs use about the same. But it adds up, especially since the military wants high resolution video. At the moment, the U.S. has far more demand for satellite communications than it can support. As a result, although the United States has six Predator and two Global Hawk UAVs in the Afghanistan area, bandwidth shortages mean that only two Predators and one Global Hawk can be in the air at one time. And even then, they have to turn off some of their sensors or use lower resolution video. 

With the growing number of UAVs, ship, ground vehicle and aircraft requirements for bandwidth, the Department of Defense expects to need at least 16 gigabits (million megabits) by 2010. But the Pentagon currently only has plans to put up satellites with about 8 gigabits capacity. Attempts to get capacity from civilian satellites is difficult because there is a shortage there as well. This was created by the tremendous overbuilding of fiber optic cable networks on the ground (and under oceans) in the late 1990s. This provides cheaper bandwidth for civilian uses and has meant fewer communications satellites being put up. In fact, the fiber optic glut reduced planned satellite launches by some 60 percent in the last few years. So a lot of the additional money for the defense budget in the next few years will be for communications satellites. Although prices for these birds is always coming down, you are still going to pay 1-2 million dollars per megabit of bandwidth. So the 16 gigabits is likely to cost over $15-20 billion.

 


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