Deep-Space Transceivers—An Innovative Approach to Spacecraft Communications

Spacecraft for deep space come in a variety of sizes as befits their missions, from the large, flagship-class spacecraft such as Cassini or Galileo to smaller craft such as New Horizons (Pluto) or Lunar and Martian landers classified by NASA as Discovery or New Frontiers missions. All missions are constrained in mass, power, or cost, or frequently all three. A communications system that reduces demands on these resources enables, for example, either increased science return (by devoting more resources to the payload) or more such missions to be flown (by helping to meet critical mass or power margins). In this paper, we review the evolution and current capabilities of deep-space transponders and transceivers, noting the differences that lend themselves to particular classes of missions. We report on the development of a flexible, low-power, low-cost, deep-space transceiver architecture for competed mission sets such as Discovery, Mars Scout, and New Frontiers, one that possesses unique communications and radio science capabilities. This state-of-the-art transceiver architecture leverages from high-performance commercial integrated circuit technology and frequency synthesis and digital signal-processing techniques, lending itself to integration, miniaturization, and further power reduction. A transceiver based on this architecture, developed for the space-borne New Horizons spacecraft's primary communications link and uplink radio science experiment, is reviewed in this paper. We conclude discussion of the modern deep-space transceiver architecture with a description of near-term and long-term future functional and performance communications and radio science enhancements to the transceiver.