Wideband Global SATCOM

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The Wideband Global SATCOM system (WGS) is a high capacity satellite communications system planned for use in partnership by the United States Department of Defense (DoD) and the Australian Department of Defence.[1] The system is composed of the Space Segment satellites, the Terminal Segment users and the Control Segment operators.[2]

A combination of Defense Satellite Communications System (DSCS) and Global Broadcast Service (GBS) satellites provide DoD wideband satellite communication services.[3] According to United Launch Alliance, quoted on Spaceflight Now, "A single WGS spacecraft has as much bandwidth as the entire existing DSCS constellation."[4]

Mission

Drawing of the Wideband Global SATCOM (WGS) satellite.

The constellation of WGS satellites increases the communications capabilities of the militaries of the United States, Canada, and Australia by providing additional bandwidth and communications capabilities for tactical command and control, communications, and computers; intelligence, surveillance, and reconnaissance (C4ISR); battle management; and combat support information. Canada has also signed on to become a partner.

WGS also augments the current Ka-band Global Broadcast Service (on UHF F/O satellites) by providing additional information broadcast capabilities as well as providing new two-way capability on that band. The combination of the Wideband Global Satellites, DSCS satellites, GBS payloads, wideband payload and platform control assets, and earth terminals operating with them has been referred to as the Interim Wideband System (IWS). It provides services to the US Dod and Australian Department of Defence. The IWS System supports continuous 24 hour per day wideband satellite services to tactical users and some fixed infrastructure users. Limited protected services will be provided under conditions of stress to selected users employing terrestrial modems capable of providing protection against jamming.

Capabilities

Diagram illustrating the payload subsystem of a WGS satellite

The WGS satellites will complement the DSCS III Service Life Enhancement Program (SLEP) and GBS payloads and will offset the eventual decline in DSCS III capability. WGS will offer 4.875 GHz of instantaneous switchable bandwidth, enabling each WGS to supply more than 10 times the capacity of a DSCS III Service Life Enhancement Program (SLEP) satellite. Once the full constellation of 6 WGS satellites is operational, they will replace the DSCS system. WGS-1 with its 2.4 Gbit/s wideband capacity provided greater capability and bandwidth than all the DSCS satellites combined.[5]

Segments

Operation and usage of the system is broken into 3 segments.

The end users of the communication services provided by the WGS are described by the DoD as the terminal segment. Users include the Australian Defence Force and U.S. Army ground mobile terminals, U.S. Navy ships and submarines, national command authorities for the nuclear forces, and various national security/allied national forces. Additionally, the Air Force Satellite Control Network will also use the WGS in a similar manner as the DSCS III constellation is used to route ATM packets through the DISA "cloud" to establish command and control streams with various satellite constellations. One of the emerging applications is SATCOM-ON-The-Move which is extensively used on the military tactical vehicles for Blue Force Tracking and C3 missions.

Satellite operators who command and monitor the satellite's bus and payload systems and manage the network operating over the satellite are the control segment. Like the DSCS constellation that WGS will replace, spacecraft bus will be commanded by the 3rd Space Operations Squadron of Schriever AFB, Colorado. Payload commanding and network control will be handled by the Army 53rd Signal Battalion headquartered at nearby Peterson AFB, Colorado with subordinate elements A Co. at Fort Detrick, Maryland, B Co. at Fort Meade, Maryland, E Co. at Fort Buckner, Okinawa Japan, C Co. Landstuhl Germany, and, D Co. Wahiawa, Hawaii.

The primary contractor for the satellites themselves is Boeing Satellite Development Center, which is building them around the Boeing 702 satellite platform. Originally five satellites were planned. On October 3, 2007, Australia's Department of Defence announced that the country would fund a sixth satellite in the constellation.[6] Once in their orbits at an altitude of 22,300 mi (35,900 km), each will weigh approximately 7,600 lb (3,400 kg). The program intends to use both the Delta IV and the Atlas V as launch vehicles. The Air Force Space Command estimates each satellite will cost approximately US$300 million.

The first three WGS satellites form Block I of the space segment. WGS satellites 4, 5, and 6 make up Block II.[7]

Launches

Block I

The first launch (WGS-1) was conducted by United Launch Alliance (ULA) on 1 October 10, 2007. The satellite was carried by an Atlas V (421) lifting off from LC-41 at Cape Canaveral Air Force Station (CCAFS). After launch, the WGS-1 satellite was given the US military designation USA-195. Its coverage area stretches from the U.S. western coast to Southeast Asia.[8]
Launch of the second satellite (WGS-2) was also conducted by ULA, at 01:31 GMT on April 4, 2009, using an Atlas V 421. A ULA Delta IV flying from LC-37B at CCAFS launched the third spacecraft on 6 December 2009. The WGS-2 satellite was positioned over the equator around 60° East longitude (over the Indian Ocean) for use by U.S. Central Command in Afghanistan, Iraq and other parts of Southwest Asia.[8][9] Originally, the second spacecraft was to fly on the Delta, and the third on the Atlas, but they were switched for an undisclosed reason.[10]
WGS-3 was launched on December 6, 2009, covers the eastern Atlantic Ocean.[11] The satellite was launched by a Delta IV "Medium+ (5,4)" rocket (originally Atlas V but switched with WGS-2; see above).


Block II

WGS-4, the first of the Block II, was launched by United Launch Alliance from SLC-37B at the Cape Canaveral Air Force Station by a Delta IV Medium+ (5,4) on January 20, 2012, 00:38 AM GMT.[12]
WGS-5 was successfully launched by a Delta IV rocket flying in the Medium+(5,4) configuration, with lift-off taking place from SLC-37B in Florida at 20:27 local time on May 24, 2013.[13]
In May, 2013, Boeing reported that the WGS-6 satellite had been shipped to Florida,[14] WGS-6 was launched on a Delta IV rocket at 20:29 EDT (00:29 GMT) on 7 August 2013 from Cape Canaveral Airforce Base.[15]

These satellites represent the Block II WGS satellites.[8][16]

On Aug. 23, 2010, Boeing was awarded an Air Force contract worth $182 million to begin work on the seventh WGS satellite. The new spacecraft is being procured under the WGS Block II follow-on contract. The contract will ultimately include options for production of up to six WGS satellites.[7]

References

  1. ↑ Australia Gets Access to Wideband Global SATCOM System
  2. ↑ "Wideband Global SATCOM Satellite". U.S. Air Force Space Command. 
  3. ↑ "Environmental Assessment - U.S. Air Force Wideband Gapfiller Satellite Program". Defense Technical Information Center. 
  4. ↑ "Pre-launch ops keep crews busy at the Cape". Spaceflight Now. 
  5. ↑ "Wideband Gapfiller System". GlobalSecurity.org. 
  6. ↑ "Australia To Fund Sixth WGS Satellite". Satellite Today. 
  7. ↑ 7.0 7.1 "Boeing Awarded Follow-on Contract for Seventh WGS Satellite". Advantecon Web Site. Advantecon. 2010-08-23. Retrieved 2010-08-23. 
  8. ↑ 8.0 8.1 8.2 "Delta 4 assigned to deliver military satellite into orbit". Spaceflight Now. January 4, 2010. 
  9. ↑ "Atlas 5 rocket successfully launches military satellite". Spaceflight Now. 
  10. ↑ "Military communications satellite successfully launched". US Air Force. Archived from the original on 2012-07-16. 
  11. ↑ Associated Press, "Rocket Launches Air Force Satellite From Fla.", Atlanta Journal-Constitution, December 6, 2009.
  12. ↑ Spaceflight Now | Delta Launch Report | Mission Status Center
  13. ↑ William Graham (May 24, 2013). "ULA Delta IV successfully lofts WGS-5 satellite". nasaspaceflight.com. 
  14. ↑ "Boeing Ships 6th Wideband Global SATCOM Satellite for Launch". Boeing. May 17, 2013. 
  15. ↑ "United Launch Alliance Successfully Launches Second Wideband Global SATCOM Mission for US Airforce in Less Than Three Months". United Launch Alliance. 07/08/2013. Retrieved 2013-08-08. 
  16. ↑ "United Launch Alliance Delta IV Rocket Successfully Launches U.S. Air Force's Wideband Global SATCOM-4 (WGS-4) Satellite". United Launch Alliance. 

External links

See also

Block I
Block II
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