CAPE CANAVERAL, Fla. -- A crucial radar antenna on a European spacecraft bound for Jupiter is no longer jammed.

Flight controllers in Germany freed the 52-foot (16-meter) antenna Friday after nearly a month of effort.

The European Space Agency's Jupiter Icy Moons Explorer, nicknamed Juice, blasted off in April on a decade-long voyage. Soon after launch, a tiny pin refused to budge and prevented the antenna from fully opening.

Controllers tried shaking and warming the spacecraft to get the pin to move by just millimeters. Back-to-back jolts finally did the trick.

The radar antenna will peer deep beneath the icy crust of three Jupiter moons suspected of harboring underground oceans and possibly life. Those moons are Callisto, Europa and Ganymede, the largest moon in the solar system.

Juice will attempt to go into orbit around Ganymede. No spacecraft has ever orbited a moon other than our own.

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