Communications from the South Pole at very low inclination angles
Intelsat General Corp. and Paradigm Secure Communications have teamed to provide broadband satellite service to the Amundsen-Scott South Pole Station, restoring communications capacity lost more than a year ago with the retirement of Intelsat's Marisat-F2 spacecraft.
Under a contract with the National Science Foundation, which operates the South Pole facility, Intelsat General will provide connectivity to the station using Paradigm's Skynet-4C satellite and Oakhanger ground station southwest of London in tandem with Intelsat's global IntelsatONE fiber network.
The population at the station ranges from around 50 in the dark winter months to over 150 scientists and support staff in the sun-lit summer. The station will rely on the SKYNET link for transferring scientific data to colleagues at universities, phones calls home, video conferencing, software updates, and emergency telemedicine.
In February, engineers successfully completed testing of the satellite connection between Oakhanger and the South Pole station using a small fly-away terminal delivered to the South Pole on short notice. The circuit is scheduled to become fully operational in January 2011 after a weather-hardened X-Band SATCOM terminal can be delivered and installed. Due to weather conditions, the station airstrip shuts down from mid-February to mid-October, halting equipment deliveries and any construction projects during the dark winter months.
Because of its location on the southern-most point of the Earth, satellite dishes at the Amundsen-Scott station are out of view of geo-stationary communications satellites orbiting the equator. However, the 20-year-old Skynet-4C satellite is in an inclined orbit and drifts slightly above and below the equatorial plane as it orbits the Earth. With its inclination now at 10.3 degrees, the satellite will be visible to the South Pole for five hours each day. As the satellite ages, the daily visibility will grow as the inclination increases.
SKYNET-4C will supplement the existing communications services provided to the South Pole station through GOES-3, a semi-retired weather satellite, and part time coverage by NASA's TDRSS fleet of spacecraft. These satellites are also in inclined orbit. Service will begin with a 2.4m X-band terminal at the pole operating a T1 circuit. The data rate may be increased in the future.
The SKYNET-4C service will replace that provided by Marisat-F2 satellite, which was launched in 1976 and had lasted more than twice as long as originally expected. It was considered to be the oldest communications satellite still actively operating in space when it was retired in late 2008. Of the three satellites dedicated to serving the National Science Foundation's research operations at the South Pole, Marisat-F2 had the greatest bandwidth capacity for Internet service and was available for use the most hours each day, officials said.
The research at the South Pole is very "data-intensive," with more than 100 gigabytes of astronomical, climate and other data being sent by satellite on some days using the satellites serving the station. In addition, the satellites are used for Internet access, e-mail and routine communications with scientists around the world interested in the South Pole research.