Polarization Combining in the DSN - Recent Results

Communications with satellites exploring other planets and objects far from Earth is provided by NASA's Deep Space Network (DSN). Deep space by its nature places a limit on return data rates. This adds to mission cost through extended contact time. Methods that increase mission data rates can substantially reduce the number of required ground contacts and overall cost; or, alternatively, they can increase science data return for a fixed amount of contact time. This paper reports on the first in-flight results of using polarization diversity combining in deep space communications to nearly double the downlink data rate. The DSN and the satellite microwave telecommunications systems are detailed, along with a model of the DSN combining gain. Test results from Mars Odyssey and the New Horizons Mission to Pluto are described, including operational constraints and potential improvements. The significant impact and benefits of this new capability are discussed.