THE STATUS OF Ka-BANt) COMMUNICATIONS FOR FUTLJRE

Over the past decade, the Jet Propulsion Laboratory’s Telecommunications and Mission Operations Directorate has invested in a variety of technologies, targeted at both the flight and ground sides of the communications link, with the goal of developing a Ka-band (32 GHz) communications capability for future deep space missions. Driving this effort is the realization that moving from the current X-band (8.4 GHz) downlink frequency up to Ka-band offers roughly a four-fold performance improvement, providing a low-cost path for increasing the aggregate capacity of NASA’s Deep Space Network and enabling new classes of small, low-cost microspacecraft On the spacecraft, future radio systems, starting with the Small Deep Space Transponder, will offer the option of Ka-band exciters for downlink telemetry. Novel Ka-band antennas offer very high gain in low-mass, confomlal packages, Ka-band Solid State Power Amplifiers have been demonstrated; however, significant improvements in both total output power and power-added efficiency are needed to achieve the full benefit of Ka-band’s performance advantages. On the ground, the DSN’S new generation of 34-meter beam waveguide antennas has demonstrated both the aperture efficiency and precision pointing necessary to support Ka-band reception; current efforts are focused on assessing the potential utility of the 70m antennas at 32 GHz.. Multi-year radiometry at all three DSN sites provides a statistical assessment of Ka-band atmospheric effects. And a series of flight demonstrations, including the current Ka-band Link Experiment on the Mars Global Surveyor spacecraft, have validated our end-to-end understanding of the communications link