In a triumph of engineering persistence, the radar antenna on the Jupiter Icy Moons Explorer (JUICE) mission, a European Space Agency (ESA) venture, has finally deployed after being stuck for weeks.

On May 12, the ESA announced that controllers had successfully managed to unfold the 16-meter-long antenna, which had initially encountered deployment issues after the mission's launch on April 13.

Originally scheduled to deploy within the first week of the launch, the antenna had only extended a third of its intended length by late April. Engineers suspected that a pin, used to secure the antenna in its stowed position during launch, had failed to separate as planned. To rectify the situation, the team devised a series of measures to loosen the pin. These measures included firing thrusters to shake the spacecraft, as well as orienting the craft to expose the antenna to sunlight and raise its temperature, in the hopes of loosening the pin.

While these efforts demonstrated some signs of progress, the antenna remained stubbornly stuck until controllers initiated the firing of a non-explosive actuator in the jammed bracket. The force generated by the actuator successfully loosened the pin, enabling the antenna to finally unfold. Subsequently, another actuator fired to complete the antenna's deployment.

The antenna in question is a crucial component of the Radar for Icy Moons Exploration (RIME) instrument, one of ten instruments on the JUICE mission. RIME is designed to explore the subsurface regions of Jupiter's large icy moons, such as Europa, Ganymede, and Callisto, with the capability to penetrate depths of up to nine kilometers.

NASA's Europa Clipper mission, set to launch in October 2024, also has its own radar instrument known as the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). The Europa Clipper team has been monitoring the RIME antenna situation closely. 

With the successful deployment of the radar antenna on the JUICE mission, scientists and space enthusiasts alike can breathe a collective sigh of relief.

The journey to Jupiter in 2031 for JUICE promises to be an exciting endeavor, offering invaluable insights into the mysteries concealed beneath the icy moons of the gas giant.