Space weather and deep space communications

While Pioneer 11 and Galileo are two deep space missions that experienced radio communication disruptions due to space weather, the success of a mission like Solar Probe, whose goal is to fly by the Sun within a few solar radii of its surface, may depend critically on space weather. It is therefore crucial to thoroughly understand how space weather affects radio communications and to identify ways to predict it. In this study, we explain how enhanced small-scale electron density variations in the solar corona represent adverse space weather to radio communications because they give rise to enhancements in radio propagation phenomena such as spectral broadening and fluctuations in intensity and Doppler of the radio signal known as scintillation. The inability of narrowband radio receivers to track the broadened and rapidly fluctuating radio signal leads to disruption in communication and loss of telemetry. Recent advances have been made in understanding enhanced small-scale density variations and their relationship to the Sun, and we show how this makes it possible to use daily observations of unprecedented solar missions like the Solar and Heliospheric Observatory (SOHO) or Solar Terrestrial Relations Observatory (STEREO) to diagnose, monitor, and forecast adverse space weather for deep space communications.