Boeing Space and Intelligence Systems of El Segundo, Calif., in December mated the payload module and spacecraft bus of the fourth satellite in the Wideband Global Satcom (WGS) constellation it is building for the U.S. Air Force, according to a Feb. 8 Boeing press release.

WGS is the military’s new generation of high-capacity X- and Ka-band communications satellites, replacing the Defense Satellite Communications System fleet. The first two satellites are now operational over the Pacific Ocean and Southwest Asia regions, respectively, and the third satellite that was launched in December is expected to enter service in April, the release said.

WGS-4 is expected to launch in 2011 or 2012, and will be the first satellite in the series to feature upgraded capabilities, including the ability to support high-bandwidth aerial vehicles. Over the next few months, the satellite will undergo some final integration activities before being subjected to vibration and thermal vacuum testing, the release said.