JUICE is free! ESA saves mission to study Jupiter’s moons

ESA specialists managed to unfold the antenna of the RIME radar installed on the JUICE spacecraft. This is one of the key tools of the mission. It will allow us to find out what is inside the icy moons of Jupiter.

JUICE Mission Challenges

The JUICE mission went into space on April 14. Its target is Europa, Ganymede, Callisto — three icy moons of Jupiter, under the surface of which giant oceans hide. The RIME radar (Radar for Icy Moons Exploration) is designed to study their interior. Thanks to its 16-meter antenna, this device will be able to scan the surface of the moons to a depth of 9 km with a vertical resolution of 30 meters.

RIME antenna on the Earth background. The picture was taken shortly after the launch of JUICE. Source: ESA

Unfortunately, the unfolding of RIME did not go according to plan at all. The selfie cameras installed on the JUICE case showed that after launch, the antenna of the spacecraft opened only a third of the required length. This called into question the possibility of fulfilling a significant part of the mission’s scientific program.

After analyzing the telemetry, ESA engineers came to the conclusion that the opening of the antenna was prevented by a stuck pin with a size of only a few millimeters. To get rid of it, experts have taken a whole series of actions designed to “shake” the spacecraft. They included both periodic activation of JUICE engines and the use of sunlight to heat the radar. However, despite some movement of the antenna, its full release did not happen.

Unfolded antenna

Therefore, the engineers resorted to the last step. On May 12, they activated a mechanical device called a “non-explosive actuator” (NEA) located in a jammed bracket. This produced a shock that shifted the pin a few millimeters and allowed the antenna to unfold. But the last part of the RIME remained folded. Then the team launched another drive in the bracket, as a result of which the antenna was completely free.

Unfolding the radar antenna of the JUICE spacecraft. Source: ESA/Juice/JMC

The unfolding of RIME was the last operation necessary to bring JUICE to a working position. At the next stage, the mission specialists will check and calibrate the main scientific instruments of the spacecraft. Recall that it will take eight years of flight to reach Jupiter.

According to https://www.esa.int

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