Advances in Microwave Technology for the MESSENGER Mission to Mercury

The MESSENGER spacecraft, designed to orbit the planet Mercury, uses the first electronically scanned phased-array antenna for a deep-space telecommunication application. Two lightweight phased arrays, mounted on opposite sides of the spacecraft, provide the high-gain downlink coverage. Medium-gain antennas are used for uplink and downlink during cruise phase. The invention of a method for achieving circular polarization in a high-temperature (+300degC) environment has doubled the science return of the mission relative to the inherent linear polarization from a slotted waveguide array. Monolithic microwave integrated circuits and discrete heterostructure field effect transistors are integrated to provide the high-efficiency X-band solid-state power amplifier.