During the first attempt at stretching out the compacted antenna, only the initial segments of each half were released. The flight controllers theorized that a minuscule stuck pin prevented the other segments from unfurling.

Luckily, the flight control teams at ESA's mission control center in Darmstadt had an abundance of potential solutions.

To attempt to dislodge the pin, they oscillated Juice using its thrusters, then warmed Juice with sunlight. Each day there were indications of movement in the RIME antenna, but it did not fully unfurl.

On 12 May, RIME was finally coaxed into action when the flight control team triggered a mechanical device known as a 'non-explosive actuator' (NEA), situated in the jammed bracket. This produced a jolt that shifted the pin by a few millimeters, enabling the antenna to extend.

The mechanical jolt resulting from the actuation in the mounting bracket was evident when the actuator was triggered at the time marked as 'NEA 6 Release'. The resulting damping oscillation signifies that the antenna has been released, and then it oscillates back and forth before stabilizing into an extended, locked position.

However, a final portion of the antenna remained compacted. Confirmation that the RIME antenna was fully deployed only came when the flight control team activated another actuator in the bracket, causing RIME to fully elongate after months being packed up for launch.

Once ESA's Jupiter Icy Moons Explorer (Juice) reaches Jupiter, it will utilize RIME to examine the surface and subsurface structure of Jupiter's icy moons down to a depth of 9 km. RIME is one of ten instruments onboard Juice poised to explore the genesis of habitable worlds around gas giants and the formation of our Solar System.

Related Links
Juice at ESA
Space Technology News - Applications and Research