The JUICE mission team behind the Jupiter system achievement reports that the RIME radar antenna has been successfully deployed on the spacecraft, a milestone confirmed by the European Space Agency. This deployment marks a crucial step in enabling the probe to peer beneath the ice of Jupiter’s icy moons and to begin its long journey of measurements and discovery.
Initial plans called for the antenna to unfurl on April 13, but the process progressed slowly, with only a partial opening by month’s end. The 16-meter folded antenna was designed to fit within the launch fairing, but its size posed a challenge for integration. A non-retractable pin impeded full deployment, and engineers spent time exploring options to unlock the mechanism. For a period, teams attempted to initiate the deployment by swinging the spacecraft and warming the support bracket toward the Sun, hoping to free the jam. A breakthrough arrived when a non-pyrotechnic drive activated the stuck elbow on May 12, moving the pin and allowing the antenna to rotate into its commanded position. Subsequent checks indicated no additional issues with the device, and mission teams continued with calibration and readiness activities for science operations.
JUICE, formally known as Jupiter Icy Moon Explorer, launched on April 14, 2023 and is on a trajectory to reach the Jupiter system in 2031 after a series of gravity assists. The orbiter carries an array of cameras and spectrographs designed to analyze the chemical makeup of Jupiter and its moons. Yet the standout instrument remains the RIME radar, which will probe beneath the ice crusts of Europa, Callisto, and Ganymede to search for hidden oceans and to map subsurface structures. The radar’s observations will be key to understanding whether liquid water exists beneath the ice, how thick the ice shells are, and what the internal dynamics of these worlds might look like. The mission profile emphasizes a synergy between remote sensing and in-situ measurements, aiming to illuminate not only the surfaces but the concealed oceans that could harbor conditions suitable for life. The science plan also includes context on the broader Jovian environment, helping scientists place ice-shell findings within the larger system of moons, magnetospheres, and radiation belts.
Earlier investigations within the outer planets have hinted at oceans beneath the crusts of several moons, with some hints coming from earlier missions and theoretical models. The JUICE mission builds on that legacy by delivering high-resolution radar data, gravity measurements, and infrared observations that together can constrain models of subsurface water distribution and thermal evolution. As the spacecraft cruises toward its targets, researchers anticipate a wealth of data that will refine our understanding of icy worlds, their potential habitability, and the dynamics that shape their oceans over geological timescales. This mission represents a major step in comparing icy moons across the solar system and exploring the diverse environments that may host liquid water below their frozen surfaces.