Solar scintillation study during planetary conjunction

摘要: During superior solar conjunction of a spacecraft, the spacecraft has limited communication with ground station due to effect Sun on RF signal transmission. Our analysis data that been obtained during several MESSENGER (MErcury Surface, Space ENivornment, GEochmeisty, and Ranging) conjunctions revealed can operate at smaller SEP angles than was reported in prior studies. Operating substantially reduce down time link conjunction. While general trend is for performance degrade decreasing angles, we have found instances where deviates from this behavior. short-term amplitude scintillation long-term phase scintillation. Amplitude produces up 3 dB degradation carrier strength over short scale (< 1 s). Phase occurs longer — 10 s 100 seconds cause deeper fades.