USA-233, or Wideband Global SATCOM 4 (WGS-4) is a United States military

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth ...

operated by the

United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...

as part of the

Wideband Global SATCOM The Wideband Global SATCOM system (WGS) is a high capacity United States Space Force satellite communications system planned for use in partnership by the United States Department of Defense (DoD), Canadian Department of National Defence (DND) ...

program, launched in 2012. The fourth

satellite, it is the first WGS Block II satellite to be launched. It is stationed at 88.5° East (

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

) in geostationary orbit.

Overview

The Wideband Gapfiller SATCOM (WGS) system is a constellation of military communications satellites. The WGS system is composed of three principal segments: Space Segment (satellites), Control Segment (operators) and Terminal Segment (users). Each WGS satellite provides service in multiple frequency bands, with the ability to cross-band between the two frequencies on board the satellite. In early 2001, a satellite communications industry team led by

Boeing Satellite Systems The Boeing Satellite Development Center is a major business unit of Boeing Defense, Space & Security. It brought together Boeing satellite operations with that of GM Hughes Electronics' Space and Communications division in El Segundo, Calif ...

was selected to develop the WGS system as successors to the

Defense Satellite Communications System The Defense Satellite Communications System (DSCS) is a United States Space Force satellite constellation that provides the United States with military communications to support globally distributed military users. Beginning in 2007, DSCS is be ...

(DSCS) series of communications satellites. This satellite communications system provides communications for military users and augments the Global Broadcast Service (GBS) and

(DSCS) satellites already operating. In March 2007, the acronym WGS was changed to Wideband Global SATCOM from Wideband Gapfiller Satellite. According to the United States Space Force Fact Sheet "Just one WGS satellite provides more SATCOM capacity than the entire legacy Defense Satellite Communications System (DSCS) constellation." Also, "As the backbone of the U.S. military's global satellite communications, Wideband Global SATCOM Satellite (WGS) system provides flexible, high-capacity communications for the Nation's soldiers through procurement and operation of the satellite constellation and the associated control systems. WGS provides worldwide flexible, high data rate and long haul communications for the Department of Defense (DOD), governmental organizations and international partners."

Satellite description

WGS-4 can transmit data at approximately 3.6 gigabits per second. It can point 19 individual beams at different points on the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

, operating at

X-band The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approxi ...

and

Ka-band The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz), i.e. wavelengths from slightly over one centime ...

frequencies. Built by

around the BSS-702HP

satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus- ...

, the satellite is expected to operate for fourteen years. Propulsion is provided by a R-4D

apogee motor An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final (most commonly circular) orbit. For a satellite laun ...

, and four XIPS-25

ion thruster An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. It creates thrust by accelerating ions using electricity. An ion thruster ionizes a neutral gas by extracting some electrons out of ...

s for stationkeeping. It is valued at US$464 million.

Launch

The launch of WGS-4 took place at 00:38:00 UTC on 20 January 2012, using a Delta IV Medium+ (5,4)

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and ...

flying from Space Launch Complex 37B (SLC-37B) at the

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

(CCAFS). The launch was conducted by

United Launch Alliance United Launch Alliance (ULA), legally United Launch Alliance, LLC, is an American spacecraft launch service provider that manufactures and operates a number of rocket vehicles that are capable of launching spacecraft into orbits around Earth, ...

(ULA), and marked the eighteenth flight of the Delta IV. The launch vehicle successfully placed the satellite into a supersynchronous geostationary transfer orbit, with 24° of

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

. Upon achieving orbit, WGS-4 was assigned its USA designation USA-233, and the

International Designator The International Designator, also known as COSPAR ID, is an international identifier assigned to artificial objects in space. It consists of the launch year, a three-digit incrementing launch number of that year and up to a three-letter code repr ...

2012-003A. The satellite used its onboard propulsion systems to inject itself into geosynchronous orbit.

References

{{Orbital launches in 2012 Spacecraft launched in 2012 USA satellites Wideband Global SATCOM Communications satellites in geostationary orbit