Mars Reconnaissance Orbiter tested the option of using Ka-band as part of a telecommunications technology demonstration.
Though the standard in deep-space communications is currently a radio wave known as X-band, future spacecraft will incorporate radio systems utilizing the Ka-band of the radio spectrum. The Ka-band frequency is four times higher than X-band (32 gigahertz compared to 8 gigahertz), which allows much higher data rates to be transmitted. Mars Reconnaissance Orbiter carried a separate Ka-band radio and demonstrated this new capability for future missions during its cruise phase.
Deep Space Network antennas capable of transmitting and receiving data through the Ka-band were requested twice per week as part of the Ka-band telecommunications technology demonstration.