Maximization of data return at X-band and Ka-band at DSN's 34-meter beam-waveguide antennas

In this paper we offer a new approach to evaluating the performance advantage of Ka-band frequency over X-band frequency for the receiving spacecraft downlink from deep space missions. For a given elevation profile for a pass, this approach uses atmospheric noise temperature statistics to select the optimum data rate to maximize the total data return volume over the pass. For illustration purposes, this approach is used to optimize the performance of a link for both X-band and Ka-band at a NASA Deep Space Network (DSN) 34 m Beam Waveguide tracking stations at both Madrid, Spain and Goldstone, California. Our calculations show that using such an approach an optimized Ka-band link offers between 5.9 dB and 7.2 dB more data volume over an optimized X-band link, and between 8.5 dB and 10.3 dB over an X-band link as currently operated by the DSN. It should be noted that the reliability of link designed in such a manner is relatively low and that a link optimized in this manner may not meet the continuity requirements of a mission. Furthermore, this approach takes only the weather effects into consideration. Other factors which may adversely affect the performance of the link are not taken into account under this approach.