Uplink array system of antennas for the Deep Space Network

Recently, arraying of large or small and distributed reflector antennas for uplink applications has attracted attention for a capability upgrade to the Deep Space Network (DSN). This interest is driven by the desire to maximize the usefulness of existing DSN large apertures in case of spacecraft emergency and to develop the necessary knowledge of how the array of small and distributed reflector antennas can meet other future uplink throughput needs. The primary challenge for uplink arraying of distributed reflector antennas for deep space applications is the lack of feedback from deep space within a reasonably short period. Furthermore, the individual reflectors (and their transmitter subsystems) are thousands of wavelengths apart, which make the phase coherence of individual transmitted signals an extremely challenging task. Because of the return light time constraints, all closed-loop calibrations and relative phase adjustments for any coherent combination of signals from individual antennas be conducted no farther than near-Earth orbits. This paper discusses the large array background, scope, and evolution, and some of the lessons learned from preliminary studies of the uplink array.