The Struggle for Ka-band: NASA's Gradual Move Towards Using 32-GHz Ka-band for Deep Space Missions

32-GHz Ka-band was first considered for deep-space use in 1976. In 1979, 1 GHz of spectrum at 32-GHz Ka-band was allocated for deep space use. Since then NASA's Jet Propulsion Laboratory (JPL) has been developing technologies and architectures necessary to support Ka-band planetary missions. This paper is a survey of JPL's effort. This survey includes a summary of early paper studies done in the 1980's and 1990's, development of the 34-m beam waveguide (BWG) antennas at the deep space network (DSN), and Ka-band experiments on Mars Observer, Mars Global Surveyor, Deep Space 1, Cassini and Mars reconnaissance orbiter spacecraft. The focus of this paper is on the technological and architectural challenges that 32-GHz Ka-band operations have presented throughout this long history. These include challenges presented by the weather and tighter pointing requirements for the spacecraft as well as the need to use multiple data rates during a pass.