Military satellite to give major communications boost
BY CRAIG COVAULT
Posted: March 16, 2009
U.S. and allied forces in Iraq and Afghanistan, who face a shortage of wideband communications, will gain major additional capability pending the successful launch of the new Wideband Global SATCOM spacecraft on its Atlas 5 rocket.
With solar arrays spanning 157 feet, the spacecraft will provide an enormous increase in communication services needed by users in the area of responsibility under U.S. Central Command, headquartered in Tampa, Fla.
The WGS series is replacing the far less capable Defense Satellite Communications System (DSCS). Each of the six planned WGS spacecraft will be based on the Boeing 702 communications satellite bus.
The sixth and final spacecraft in the series has been ordered by Australia.
The first of five WGS spacecraft for the U.S. Defense Dept. was launched from Cape Canaveral in October 2007. This first spacecraft is providing communications to all military services operating in the Pacific theatre.
One WGS has the communications throughput capability of the entire DSCS fleet. In fact, during operational testing with the first satellite, the government successfully transmitted a record-breaking 440 megabits-per-second of communications through the original spacecraft.
The standard WGS transmission capability will be 2.5-3.3 gigabits per second -- 10 times faster than an individual DSCS.
The new WGS satellites have a unique frequency conversion capability that will allow users on one frequency to communicate through the same satellite with a user on a different frequency.
The satellite will operate in the 500 MHz range of X-band and the 1 GHz range of Ka-band, routing and cross filtering up to 4.875 GHz of instantaneous bandwidth.
Each spacecraft can serve nearly 20 independent coverage areas. It can provide up to eight steerable and shaped X-band spot beams formed by separate transmit/receive phased array antennas. Along with that, it can project 10 Ka-band beams by independently steered and diplexed antennas, including three with selectable RF polarization.
The new satellite will be involved in serving a wide range of users from routine email through the routing of high resolution intelligence imagery, video and commands for the piloting of Predator unmanned aerial vehicles (UAVs).
It will also be useful for clandestine operations.
Added satcom capability will be welcome, says U.S. Air Force Capt. Wade H. McGrew, who leads the Space Applications Course taught at the Special Operations School at Hurlburt Field, Fla. The school prepares Special Operations personnel for often secret operations in Iraq and Afghanistan, as well as other areas of the world.
In addition to teaching the course, McGrew has seen action with the Special Forces himself in Iraq.
"We need larger amounts of data faster," McGrew says. "As the [capability for] for more data grows we continue to grow our uses right along with it," he says.
Capt. McGrew's educational work in the field and at Hurlburt to broaden the Special Forces' use of space recently earned him the 2009 National Defense Space Award from the National's Space Club's Florida Chapter.
The need for even more bandwidth will become more acute in the future, as the Army fields its Future Combat System (FCS) designed to link far more vehicles with computer displays. Much greater use of UAVs and ground-based robotic vehicles will also increase bandwidth needs that the WGS capabilities will begin to address.
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