Interplanetary spacecraft missions rely on ground-based radio telescopes for command and control operations, and nominal telemetry. Spacecraft radio communications can be used to conduct radio science experiments by utilizing radio telescopes as receivers. These experiments involve analysing various properties of the transmitted signal, including Doppler shift, interplanetary phase scintillation [1], and performing interferometry. PRIDE is a technique developed to enhance the scientific return of spacecraft missions by performing radio science experiments and obtaining precise orbit determination.
The PRIDE technique relies on observing the Doppler shifts of the signal to obtain the spacecraft’s radial velocity. Additionally, near-field phase-referencing VLBI is used to measure the spacecraft’s lateral position. These measurements can be used to refine the spacecraft state vectors along with a variety of radio science applications including:
• Measuring the interplanetary scintillation between the spacecraft and the Earth, and subsequent determination of the contribution of the ionised plasma from the solar wind and coronal mass ejections [1].
• Modelling of the vertical pressure and temperature profiles of gaseous atmospheres of planets via radio occultation experiments [2].
• Precise measurements of the gravitational field parameters of planetary bodies as well as improving their ephemerides [3].
• Measuring the wind profiles of planetary atmospheres [4].
PRIDE is one of the eleven experiments contributing to the JUICE spacecraft mission [5]. Launched on April 14th, 2023, JUICE commenced an eight-year cruise phase with a series of flybys of the Earth, Moon and Venus. PRIDE-JUICE will support JUICE throughout the cruise phase through precise spacecraft tracking and performing radio science experiments to study space weather, the dynamics of the spacecraft and ensuring the overall health of the mission before reaching the Jovian system.

Upon JUICE’s arrival in 2031, there will be many milestones in which PRIDE will make measurements of Jupiter and its icy moons. For example, precise spacecraft VLBI tracking will enable analysis of the moons’ gravitational field parameters, facilitating investigation of their interiors and their tidal evolution. This is achieved with minimal requirements on the spacecraft’s payload, with measurements performed only using the radio signal from the regular spacecraft transmissions [5].
The University of Tasmania (UTAS) is an important member of PRIDE-JUICE through its continental-wide network of radio telescopes. The UTAS Hb (Hobart, Tasmania), Ke (Katherine, Northern Territory) and Yg (Yarragadee, Western Australia) 12m radio telescopes, as well as the Cd (Ceduna, South Australia) 30m, and Ho (Hobart, Tasmania) 26m have been used for these observations. PRIDE Doppler observations have been conducted since its launch in 2023, and PRIDE VLBI phase-referencing observations since 2024.
This paper is divided into three content sections. The Observation Technique section details the principles behind the PRIDE VLBI technique. Next, the PRIDE VLBI implementation at the University of Tasmania is discussed, with the observation methodology and data processing pipeline implemented. Finally, the results of four PRIDE VLBI experiments in July and August 2024 are detailed, including the successful imaging of the spacecraft and natural radio sources, along with the PRIDE Doppler observations.