domingo, 8 de agosto de 2010

U.S. Department of Defense has launched Wideband Global SATCOM communications satellite.

The U.S. Department of Defense has launched its third WGS (Wideband Global SATCOM) communications satellite, and got it working. This happened three year after the first one went into orbit, and six years after the first one was supposed to go up. The third WGS bird was actually launched last December, but only officially entered service on August 2nd, after months of checkouts and testing. The WGS is a six ton satellite with a traffic handling capacity of 3.6 gigabits a second.
WGS originally stood for "Wideband Gapfiller Satellite" and they are actually modified versions of the Boeing 702 communications satellite. Boeing has built or has orders for over 20 of the commercial 702s, which are built on the earlier, and very successful, 600 series communications satellites. Using the 702 as a model for WGS seemed like a slam-dunk initially, basing needed military commo birds on a solid civilian model. A few tweaks and additions to deal with military security needs, and off we go. The Department of Defense wants to build six WGS birds, at a cost of some $220 million each. The WGS has ten times the throughput (3.6 gigabits) of the earlier DSCS III commo satellites. The first WGS bird in orbit more than doubled the transmission capacity of the Department of Defense satellite system.
There is a growing need for more commo birds. Between 2000 and 2002, Department of Defense satellite bandwidth (data transmission demand) doubled, and more than doubled every 18 months after that. Back in 2000, some 60 percent of Department of Defense satellite capacity had to be leased from commercial firms. While the Department of Defense had its own communications satellite network (MILSAT), it underestimated the growth of demand. Greater use of the internet and reconnaissance aircraft and UAVs using video cameras quickly used up MILSATs capacity and forced the military to lease capacity on commercial satellites. 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.
It was only two decades ago that the U.S. armed forces moved 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 1,300 simultaneous phone calls. Or, 12 megabits 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 per second, and Predators about half as much. The major consumer of bandwidth is the live video. Thus data transmission capability (“bandwidth”) has gone from 46 megabits (million bytes) per second in late 2001, just for troops in CENTCOM (the Middle East and Afghanistan), to nearly ten giga (billion) bits per second now. Thus the rush to get those WGS birds up.
Attempts to get capacity from civilian satellites was complicated by the fact that there was 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 provided 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 for the first few years of this decade.
The solution was the WGS birds, with the first supposed to launch in 2004. But there were design problems, manufacturing problems, and scheduling problems getting an American launcher (having a Russian or Chinese rocket put these birds into orbit was not an option, for security reasons.) These problems have been solved, with three WGS birds launched in the last three years, and the other three in the next three years That will provide more capacity, but still not be enough.

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