Denver-based United Launch Alliance (ULA) said Jan. 4 it has received a contract modification from the U.S. Air Force Space and Missile Systems Center to launch the Wideband Global SATCOM-4 (WGS-4) satellite aboard a Delta 4 rocket.

The launch is slated to occur between December 2011 and February 2012 from Florida’s Cape Canaveral Air Force Station.

WGS-1 and WGS-2 launched on ULA Atlas 5 rockets in 2007 and 2009, respectively. WGS-3 launched Dec. 5 aboard a Delta 4.

The WGS satellites are part of a high-capacity communications system meant to provide near-global coverage for the U.S. military.