Analysis of the radio frequency effects of interaction of the Parker Solar Probe spacecraft's onboard antennas with ionosphere of Venus and use of electrically small antennas in space communications

In 2021, NASA published data on radio frequency effects resulting from the interaction of the onboard antennas of the Parker spacecraft, obtained by observing the night side of Venus. Four pin antennas of the device protruding beyond its heat shield measured electric field fluctuations in two planes, and the fifth pin antenna determined the position of electrical fluctuations in three-dimensional space. Since these antennas are sensitive to changes in the electrical properties of the medium, depending on the concentration of electrons and ions, it was possible to identify several regions of the charged ionosphere of Venus. The purpose of this work is to analyze the radio frequency effects resulting from the interaction of the onboard antennas of the Parker spacecraft with the electric and magnetic fields of Venus. Spectral-temporal visualization of the received audio signal has been used as a method for studying the radio frequency effects that occur when the antenna interacts with the ionospheric gas of Venus. Using this method, the amplitude, time, and frequency characteristics of the radio signal have been analyzed, allowing us to evaluate its spectral expansion and the appearance of harmonics, changes in the electron-ion conductivity of the medium, and draw conclusions about the possible causes of the effect. A table has been compiled in which the effects leading to these spectral features are described. It has been shown that the main causes of radio frequency effects in these areas are differences in the complex dielectric constant of the medium, linear and nonlinear scattering of radio signal energy in the antenna-feeder path, as well as the dynamics of the Parker spacecraft during a flyby of Venus and ions ejected at different speeds by engines during trajectory correction. In the future, it is of great interest to supplement these studies with radio measurements in the decameter and hectometer ranges of radio wavelengths. To operate at these frequencies, it has been proposed to use resonant spiral electrically small antennas operating in a narrow frequency band. The influence of cosmic factors on the characteristics of these antennas is less than that of pin antennas. They can be used with small-sized digital transceiver equipment for receiving and processing geophysical signals, as well as for receiving and transmitting data from other spacecraft or to Earth. The dependences of the wire length and diameter, the resonant frequency, and the mass of an electrically small spiral antenna on the number of turns in one layer have been given. The results obtained make it possible to better understand the interaction of antennas with space plasma for future space programs, as well as the processes in the ionosphere of Venus. The use of resonant spiral electrically small antennas in deep space communication lines has been proposed.