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.