WGS 4 (USA 233)

Spacecraft n°:

US spacecraft n°:

Launch data: Designation  38070 / 12003A Launch date  20 Jan 2012 - 00:38:00 UT Launch site  CC, SLC-37B Launch vehicle  Delta-4M+(5,4) Mission  Military: Communication Geostationary orbit on Feb 28.50: Perigee / Apogee  35783 x 35785 km Eccentricity  0.00002 Inclination  0.09 deg Period  1435.98 min

An artist's concept of WGS antenna arrangement. Credit: Boeing

Description:

• WGS F4 is an Air Force satellite headed for service over the Middle East to route essential communications to U.S. military forces and improve data links to unmanned aerial drones. Dropped off into a highly-elliptical, preliminary orbit by the Delta 4 rocket, the satellite's conventional bi-propellant chemical main engine will execute four apogee and four perigee firings through early February before beginning 40 days of final orbit circularization maneuvers with its xenon-ion propulsion thrusters to reach geosynchronous perch 22,300 miles (35,888 km) above Earth in March. The Air Force says it plans to put this WGS 4 spacecraft's coverage footprint over the Middle East and Southeast Asia for use by U.S. Central Command and U.S. Pacific Command. Once slid into its orbital home high above the Indian Ocean, the satellite will join the expanding fleet of Wideband Global SATCOM communications satellites that form the Pentagon's worldwide communications backbone across all branches of the military. The craft's communications package provides shaped, steerable spotbeams of bandwidth wherever requested across its field-of-view for Ka- and X-band frequencies, plus the onboard capability to switch signals from one band to the other.
• X and Ka-band transponders. Will replace DSCS system.

Mission details:

• The 4th Wideband Global Satcom satellite was launched on Jan 20 into supersynchronous geostationary transfer orbit. The Boeing 702 satellite provides high bandwidth communications for the US military and is operated by US Army Space Command.