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Comberiate Glacier () is a glacier flowing west from the Royal Society Range between Berry Spur and Utz Spur. It was named by the Advisory Committee on Antarctic Names (1994) after Michael A. Comberiate, who was instrumental in developing a system for satellite communications to and within Antarctica, the South Pole Satellite Data Link. Known thereafter as "NASA Mike", Comberiate composed an unsolicited proposal while at the South Pole Station at 90 South on 19 December 1983 to use scientific Polar-orbiting satellites already in polar orbits to relay data from 90S to the McMurdo Station on the coast of Antarctica. At that time there were no communications satellites of any kind in Polar orbits and those in Geosynchronous orbits could not see the 90S station. The proposal was unique in that the ranging channels on-board some satellites such as Nimbus 7, Landsats 4 & 5, and Dynamics Explorers 1 & 2, were capable of relaying data but that was never an intentional design feature. These channels were used to return ranging tones to the ground so that the doppler shift could be used to determine the satellite's Distance (range) and Velocity (range rate). Comberiate saw that data from the 90S station could be sent over this ranging channel to these satellites while they were co-visible with McMurdo Station (77.5S x 166.4E) and then sent via the first geostationary satellite link (Inmarsat) that was just then being established in McMurdo (1983). The system was installed and became operational exactly one year to the date when it was proposed (19 December 1984). Although this was a voluntary effort with only miscellaneous funding, it was supported logistically by both NASA (where Comberiate was employed as an engineer) and the National Science Foundation (NSF-OPP). Nevertheless, it worked almost continuously for about 9 years. There were over 40 opportunities every 24 hours using the Nimbus and Landsat satellites mentioned above where the periods of co-visibility between the two stations was from 5 to 15 minutes. The initial data rates were 10kbps and increased to 20kbps the following year (1985), limited only by the size of the 6-foot dishes originally installed at each ground station and the 500kbps channel bandwidth. These two ground stations were the first satellite communications systems on the continent of Antarctica. They employed steerable 6-ft dishes, with special materials and greases, local heaters for the motors, and space age insulation for the pedestals to contain that heat; enabling them to operate at the extreme temperatures exceeding -102 F at the South Pole. They opened the way for all the other ground stations that eventually followed, starting some ten years later in 1995. The antenna used at the 90S station is now in the Canterbury museum in Christchurch, New Zealand, as an historic artifact that first brought Space Age Communications to the Continent of Antarctica, where previously there had only been HF Radio. Note that Teletype over HF radio (bouncing off the ionosphere) was 75 bits per second (bps) with errors every 100 bits on a good day. Often, however, it was blacked out for days and weeks at a time without warning. The South Pole Satellite Data Link (SPSDL), however was communicating at S-Band (2.0 - 2.3 Giga bps) Carrier Wave, which was line-of-sight but not affected by weather conditions. SPSDL sent 10kbps data across the continent without errors several times every day as needed. It was a revolutionary improvement on data communications for this continent. The other ground station located in McMurdo Station, however, was modified in 1994 to support satellite launches out of Lompoc, California (Vandenburg Air Force Base) heading into polar orbits. The first ground station any such satellite would pass over would be this one in McMurdo and it would see every orbit of every polar-orbiting satellite in those polar orbits. This system was renamed, the NASA Antarctic Interactive Launch Support (NAILS) system. It functioned routinely supporting launches and early orbits and special orbital operations where immediate communications back to the satellite control centers was desired. On January 4, 2013 the NAILS system was finally decommissioned and returned to the USA where it is in storage. Hopefully this antenna will also find its way into an historic exhibit, because it has surely been pathfinder. Among its historic firsts and in addition to those historic firsts as the SPSDL pathfinder, the NAILS was: - the first satellite launch support system from Antarctica; - the first to use the emerging Internet to relay data and encrypted commands from the USA to a satellite (Nimbus 7) via the continent of Antarctica; - the first realtime imaging of satellite realtime data (of the Total Ozone from the TOMS-EP satellite were collected in realtime by NAILS every orbit as it passes overhead. These images were used by NSF scientists to launch scientific balloons into the Antarctic Ozone Hole. ); - the first unmanned, semi-autonomous satellite tracking and data collection system operating in Antarctica (NAILS was programmed and could be controlled from the USA and then it would autonomously execute the program when the satellites were visible ); - the first satellite ground station in Antarctica to use a software-defined radio for its RF Receiver. As a side note, Michael A. Comberiate also introduced the first Geosynchronous Satellite Communications System on the Continent of Antarctica in December 1983, along with his SPSDL ground stations. This system established the ATS-3 (Advance Telecommunications Satellite #3) terminal at the 90S station. It began daily voice and email communications for 4 to 5 hours every day on December 15, 1984, between the South Pole and the Continental USA (CONUS) terminal in Melbourne, Florida. From there users at 90S were patched into the phone and email networks in the USA and could communicate to anyone with the clarity of typical phone lines, for many hours every day. ==References== * 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Comberiate Glacier」の詳細全文を読む スポンサード リンク
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