Deep space weather radio observations of JUICE spacecraft with VLBI radio telescopes

The Jupiter Icy Moons Explorer (JUICE), launched by the European Space Agency on April 14th, 2023, is on an eight-year journey to the Jovian system, arriving in July 2031. Among its eleven experiments, the Planetary Radio Interferometric and Doppler Experiment (PRIDE) stands out conduction Earth-based radio measurements. PRIDE leverages a network of Very Long Baseline Interferometry (VLBI) radio telescopes worldwide to perform radio science experiments [Gurvits 2023]. These experiments include radio occultation studies of Jupiter’s atmosphere, monitoring space weather, and precisely determining the dynamics of the JUICE spacecraft, and the ephemerides of Jupiter and its moons. For instance, these ephemerides are essential for understanding the long-term orbital and interior evolution of the icy moons, shedding light on their tidal interactions and geological history.

The University of Tasmania (UTAS) plays a role in this mission through its operation of a continent-wide network of five large radio telescopes: Hobart-12m, Katherine-12m, Yarragadee-12m, Hobart-26m, and Ceduna-30m. Since 2010, these telescopes have been used for planetary tracking by conducting radio science experiments to support missions such as Venus Express, Mars Express, and BepiColombo [Molera Calves 2021]. During the 2023-2024 period, UTAS’s VLBI radio telescopes have been actively monitoring the X-band radio downlink signals from various spacecraft, including Mars Express, Tianwen-1, BepiColombo, Solar Orbiter, and JUICE [Kummamuru 2023, Maoli 2023, Noor 2025 and Edwards 2025]. These observations are particularly valuable during solar conjunctions, when the spacecraft are aligned with the Sun, allowing for precise measurements of the solar corona. In addition, several we have reported and studied the transit of Coronal Mass Ejections (CMEs) across the radio propagation path. These observations provide estimates of the propagation and velocities of CMEs, enhancing our ability to forecast space weather events and their potential impacts.