Third WGS Satellite To Complete Initial Constellation
WASHINGTON — The U.S. Air Force’s third Wideband Global Satcom (WGS) satellite is scheduled to launch Dec. 2 to complete the initial constellation and provide near-global satellite communications coverage for the U.S. military.
The WGS-3 satellite, built by Boeing Space and Intelligence Systems of Seal Beach, Calif., was shipped to Cape Canaveral Air Force Station, Fla., Sept. 29 and completed functional testing at the end of October. It was transferred to the launch pad and mated with its 4 launch vehicle Nov. 14 to undergo final preparations, Mark Spiwak, Boeing’s WGS program director, said in a Nov. 23 conference call with reporters.
The WGS constellation is replacing the military’s legacy X-band Defense Satellite Communications System (DSCS) fleet, the last of which was launched in 2003. Each of the 5,940-kilogram, geostationary-orbiting WGS satellites can route up to 3.6 gigabits of data per second, roughly 10 times the capacity of the DSCS satellites. In addition to X-band capacity, WGS satellites also have Ka-band antennas and on-board digital channelizers that allow users on different frequencies to communicate. The Air Force plans to eventually maintain a constellation of eight WGS satellites.
The first WGS satellite was launched in October 2007 and is operating over the Pacific Ocean. The second satellite was launched in April and since August has been supporting U.S. forces in Iraq and Afghanistan. WGS-2 has been primarily used to support the Air Force’s Global Broadcast Service, a one-way downlink capability that delivers intelligence and surveillance products such as full-motion video from aerial vehicles as well as entertainment content, including sporting events and other television programming, Air Force Col. Bill Harding, vice commander of the Military Satellite Communications Systems Wing, said during the teleconference.
WGS-3 will be placed in an orbital slot at 12 degrees west over Europe and Africa but will overlap the footprint of WGS-2 and provide some capacity to the Middle East. The satellite is expected to be handed over to the Air Force in February and support military operations beginning in April, Harding said. With the first three WGS satellites on orbit, the constellation will cover almost the entire Earth except for a portion of the western United States, Boeing spokesman Bob Pickard said.
The Australian government in 2007 announced it would partner with the U.S. and fund the sixth satellite in the WGS constellation in exchange for a portion of the entire constellation’s bandwidth.
Boeing is under contract to deliver a total of six WGS satellites and has ordered long-lead parts for the seventh and eighth craft in the series. The next three satellites are scheduled to launch in succession in 2011, 2012 and 2013. The so-called Block 2 spacecraft will feature several upgrades, including modifications to two of the satellites’ Ka-band antennas and the ability to reroute signals around the digital channelizer in order to support higher-bandwidth aerial video feeds, Spiwak said. Boeing has previously suggested that additional upgrades could be made to the next block of satellites starting with the seventh, potentially including satellite-to-satellite laser links and additional antennas for communications-on-the-move applications.
The launch of WGS-3 will represent several milestones for the Air Force, said Lt. Col. Dave Hook, commander of the 5th Space Launch Squadron at Cape Canaveral. It will be the first Delta 4 rocket to launch a WGS satellite, as the first two were launched on Atlas 5 rockets, both of which are built byof Denver under the Air Force’s Evolved Expendable Launch Vehicle program. This also will be the first launch of a Delta 4 rocket configured with four solid-rocket motors and a five-meter fairing, Hook said. And it will be the eighth Evolved Expendable Launch Vehicle launch conducted in 2009, including two commercial launches, marking the most prolific year in the program’s seven-year history.