Space: Silence From Above

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August 23, 2008:  For about two decades now, the U.S. military has been scrambling to try and provide all the satellite communications capacity the troops are demanding. During the 1990s, the U.S. armed forces began moving to satellite communications in a big way. This made sense, especially 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 bandwidth. The Global Hawk needed 500 megabits per second, 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 more high resolution video.

Between 2000 and 2002, Department of Defense satellite bandwidth (data transmission demand) doubled, and more than doubled every 18 months after that. By 2003, demand was 7 gigabits (thousand megabits) a second. That grew to 12 gigabits in 2007. With the growing number of UAVs, ship, ground vehicle and aircraft requirements for bandwidth, the Department of Defense expects to need more than 16 gigabits by 2010.

Back in 2000, some 60 percent of Department of Defense satellite bandwidth demand had to be bought from commercial firms. This was done on the "spot market," meaning the Department of Defense had to pay whatever the market would bear at that moment. Since the military needed more capacity because of combat operations, the media was also in the market for more capacity to cover the war. The Department of Defense paid more than ten times as much as it would have if it had leased (for one to fifteen years) satellite capacity earlier. The situation was made worse by the fact that it was an emergency situation, so every heavy user of satellite communications was making their own deals. This resulted in some users (air force, or, say, the Atlantic Fleet) having some extra capacity when someone else, like Army Special Forces, was still short.

At the moment, the U.S. has far more demand for satellite communications than it can supply. As a result, less than half the Predator and Global Hawk UAVs in combat zones have sufficient bandwidth to send their video back to the United States. Data compression and using lower resolution is often necessary, or using satellite substitutes (aircraft carrying transponders) to send the video to local users.

Plans to put up more military comm-sats have been delayed because the problem is not sexy enough to attract the money, and political support, it needs. This is made worse by the fact that the military wants satellites that encrypt their data and are protected from attack. Both of these items nearly doubles the cost of the satellites (to about two billion dollars each). But one of these birds can provide four gigabits of throughput per second.

As more military users chase after less satellite capacity, they will encounter more situations where they simply will not get what they want. In a way, this is good, because it forces users to find alternatives. This is what they would have to do in a war where comm-sats were being shot down.

 

 

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