HELIOS ‐ Highly rEliable Links durIng sOlar conjunctionS

Kurzfassung

During deep space missions, maintaining reliable communication between a spacecraft and Earth becomes particularly challenging during superior solar conjunctions, when the spacecraft passes behind the Sun relative to Earth. The highly ionized solar corona and solar wind create plasma inhomogeneities that severely affect radio signals, leading to phase scintillation, amplitude fading, and signal loss. These effects intensify as the Sun-Earth-Probe (SEP) angle decreases, resulting in frequent disruption of phase-locking techniques crucial for successful signal demodulation. This paper comprehensively analyzes the communication subsystem to ensure reliable tracking, telemetry, and command (TT&C) links during superior solar conjunctions. By analyzing the effects of solar plasma on radio links, the paper proposes new operational methods and subsystem architectures that enhance the robustness of RF communication even in very harsh conditions. The solutions include modulation, coding, non-coherent demodulation methods, and alternative channel models to mitigate scintillation effects and maintain stable communication links, particularly at low SEP angles. These strategies offer promising ways to improve data transmission reliability and maximize mission success during challenging solar conjunction phases.