DSCS Satellite
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Defense Satellite Communications System (DSCS)

The National Science Foundation (NSF) secured arrangements with the U.S. Strategic Command to access the Department of Defense's (DoD) Defense Satellite Communications System (DSCS) constellation of military satellite communications (MILSATCOM) satellites. This arrangement is similar to that obtained commercially via Intelsat General System and Airbus Space and Defense for access to the United Kingdom's Skynet MILSATCOM system.

The 9 Meter Radome at Amundsen-Scott South Pole Station.
Photo Credit: Chet Waggoner
The Radio Frequency Sector at Amundsen-Scott South Pole Station.

The NSF South Pole DSCS link currently uses the DSCS-3 B7 satellite - launched in 1995. It is maintained in a high inclination geosynchronous orbit, making it capable of providing limited daily coverage between South Pole Station and an NSF gateway teleport implemented at the International Antarctic Center in Christchurch, New Zealand.

The South Pole DSCS Communications Link Mission Patch
Graphic Credit: Patrick Smith
The South Pole DSCS Communications Link Mission Patch.

The Satellite is operated by the 3rd Space Operations Squadron (3SOPS) at Schriever Air Force Base in Colorado Springs, Colorado. NSF access is coordinated via the U.S. Strategic Command with direct assistance by the Army Forces Strategic Command (ARSTRAT). NSF is an approved MILSATCOM user, and is sponsored by the Office of the Secretary of Defense's Chief Information Officer's (CIO) Office. The satellite link was declared operational in early June 2016 as the successor system to the decommissioned service via the NSF GOES-3 satellite, which occurred later that month.

Satellite Link Information
Satellite DSCS-3 B7
Manufacturer Lockheed Martin
Design Life 10 years
International Designator 1995-038A
Launch Date July 31, 1995
Operating Frequency Range Military X-Band
Daily Contact Window 3.5 hours (increasing annually)
Daily Window Opening Reference the Weekly Satellite Service Schedule
Uplink (outbound) 10 Mbps
Downlink (inbound) 30 Mbps
South Pole Terminal 2.4 m aperture VSAT
Christchurch Terminal 2.4 m aperture VSAT

The system uses a VSAT (very small aperture terminal) designed by Global Satcom Technology, Inc.; it is identical to the Skynet MILSATCOM link. This provides a common systems architecture, operational management, and spare parts. The Christchurch terminal is located on the roof of the International Antarctic Center.

International backhaul communications from the Christchurch terminal to the USAP wide area network hub in Denver is provided via a secure virtual private network (VPN) link via commercial Internet Service Providers.

Planning is in progress for the conversion of the now inactive South Pole 9-meter terminal - previously used for GOES-3 L/S-band communications - into a more capable X-band DSCS terminal. The larger size of the antenna has the potential to provide higher data rates via the DSCS satellites. The existing 2.4 meter VSAT terminal will be repurposed as a DSCS terminal backup, and a prime terminal for the Skynet MILSATCOM link.