Interplanetary scintillation observation and analysis using Martian spacecraft downlink signal from VLBI station

Abstract

The Mars Express (MEX) passed through superior solar conjunction in June, 2015. The X-band telemetry signal of MEX with solar offset R in the range of 11 R⊙~160 R⊙ were recorded by Sheshan VLBI station. Phase scintillation and its power spectral were extracted from VLBI broadband recording system. The phase scintillation spectral were power-low in the range of 3 mHz~0.3 Hz, and the corresponding refraction spectral index are kept constantly with −3.3±0.25 over the full range of solar offset from 11 R⊙~160 R⊙, which is consistent with Kolmogorov turbulence. The structure constant of refractive index fluctuation has a relation of ~ R −1.98±0.27 with R , which indicates that the turbulence near solar is much stronger than that far from solar. The total electron content along the light sight (TEC) through the solar wind was acquired with phase scintillation index. The change trend of TEC is consistent with the TEC calculated using models from both solar active and quiet periods. The Doppler measurement method and interplanetary scintillation based on VLBI station can be used in solar conjunction with Chinese Mars explorer in the future.