Results from two years of Ka-band propagation characterization at Svalbard, Norway

Over the next several years, NASA plans to launch several earth science missions which are expected to achieve data throughputs of 5–40 terabits per day transmitted from low earth orbiting spacecraft to ground stations. The current S-band and X-band frequency allocations in use by NASA, however, are incapable of supporting the data rates required to meet this demand. As such, NASA is in the planning stages to upgrade its existing Near Earth Network (NEN) polar ground stations to support Ka-band (25.5–27 GHz) operations. Consequently, it becomes imperative that characterization of propagation effects at these NEN sites is conducted to determine expected system performance, particularly at low elevation angles (< 10deg) where spacecraft signal acquisition typically occurs. Since May 2011, NASA Glenn Research Center has installed and operated a Ka-band radiometer at the NEN site located in Svalbard, Norway. The Ka-band radiometer monitors the water vapor line, as well as 4 frequencies around 26.5 GHz at a fixed 10 deg elevation angle. Three-year data collection results indicate good agreement with models and comparable performance to previously characterized northern latitude sites in the United States, i.e., Fairbanks, Alaska. The Svalbard data is used to derive availability results for an upcoming earth-observation mission, JPSS-1, and indicate a requirement of 4 dB of atmospheric attenuation margin necessary to close the link with 99% overall system availability for the expected LEO orbital cycle, as observed from the Svalbard location.