Galileo Telecommunications

This chapter describes how the Galileo orbiter received and transmitted data with the Deep Space Network (DSN). The relay communications subsystems and the link between the Galileo probe and the orbiter are also described briefly. The chapter is at a functional level, intended to illuminate the unique mission requirements and constraints that led to both design of the communications system and how the mission had to be modified and operated in flight. The orbiter was powered by two radioisotope‐thermoelectric‐generators. The Galileo orbiter combined features of spinner spacecraft and three‐axis‐stabilized spacecraft. The Galileo telecommunications system was on the spun section of the dual‐spin orbiter. The system consists of four hardware subsystems: Radio frequency subsystem (RFS); Modulation demodulation subsystem; S‐/Xband¹⁰ antenna subsystem; and X‐ to S‐band downconverter. The HGA deployment phase began when the temperature control constraints permitted Earth‐pointing of the HGA. Solar conjunction was difficult for communications because the radio signals.