A JUICE instrument for scanning the subsurface structure of Jupiter’s icy moons has finally been extended to its full length after stubbornly refusing to do so since launching last month.
JUpiter ICy moons Explorer, or JUICE for short, is on an eight-year journey to Jupiter, where it will explore Europa, Ganymede, and Callisto—three Gallilean moons suspected of harboring subsurface oceans and potentially habitable conditions. This is the European Space Agency’s first mission to Jupiter, which will reach the Jovian system in 2031 and perform scientific observations until 2034.
JUICE got off to a good start, launching to space on April 14, but flight controllers ran into issues when attempting to deploy the probe’s ice-penetrating Radar for Icy Moons Exploration (RIME) antenna. The antenna remained lodged within its mounting bracket, keeping it to roughly one-third of its fully intended length. Engineers with the mission blamed a tiny stuck pin for the anomaly, saying it was problematically holding other segments in place.
That RIME refused to open was a frustrating development, but the glitch did not threaten the mission. JUICE is equipped with nine other scientific instruments for studying the Galilean moons’ geology, chemical composition, and potential to harbor life. That said, the inability to run radar scans and peer below the icy surface at depths reaching 5.6 miles (9 kilometers) would’ve represented a serious limitation to the mission.
Flight controllers devised several strategies to dislodge the stuck antenna, including a kind of shake ‘n bake method, in which the probe’s thrusters provided the shaking and the Sun’s rays provided the baking. This procedure was done over the course of several days, as controllers spun JUICE around to periodically move the mount and radar out from the cold shadows and into the light. This resulted in partial movement, but the antenna largely stayed put.
Success finally came earlier today, with controllers firing a “non-explosive actuator” affixed to the jammed bracket. “This delivered a shock that moved the pin by a matter of millimetres and allowed the antenna to unfold,” ESA explained in a May 12 statement. The firing of a second actuator allowed the final part of the stuck antenna to fully deploy, and the entire apparatus extended to its fully intended length.
And thank goodness for that. Hopefully we won’t hear much more from JUICE in the coming years as the probe winds its way to Jupiter.