ESA Juice’s RIME Antenna Breaks Free After Some Jiggling And Percussive Action

After ESA’s Jupiter-bound space probe Juice (Jupiter Icy Moons Explorer) launched on April 14th of this year, it initially looked as if it had squeezed out a refreshingly uneventful deployment, until it attempted to unfurl its solar panels and antennae. One of these antennae, for the RIME (Radar for Icy Moons Exploration) instrument that uses ice-penetrating radar to get a subsurface look at Jupiter’s moons, ended up being rather stuck. Fortunately, on May 12th it was reported that ESA engineers managed to shock the sticky pin loose.

Release of the jammed antenna coinciding with the actuation of the NEA ('NEA 6 Release'). The antenna wobbles about before settling in a locked position. (Credit: ESA)
Release of the jammed antenna coinciding with the actuation of the NEA (‘NEA 6 Release’). The antenna wobbles about before settling in a locked position. (Credit: ESA)

We previously covered the discovery of Juice’s  RIME antenna troubles, with one of the retaining pins that hold the antenna in place in its furled position stubbornly refusing to shift the few millimeters that would have allowed for full deployment. Despite the high-tech nature of the Juice spacecraft, the optimal solution to make the pin move was simply to try and shake it loose.

Attempts were initially made using the spacecraft’s thrusters to shake the whole vehicle, as well as by warming it in sunlight. Each of these actions seemed to help a little bit, but the breakthrough came when a non-explosive actuator (NEA) was actuated in the jammed bracket. This almost fully fixed the problem, leading the team in charge to decide to fire another NEA, which finally allowed the pin to fully shift and the antenna to fully deploy and lock into place.

Assuming no further issues occur during Juice’s long trip through the Solar System, Juice is expected to arrive at Jupiter after four gravity assists in July of 2031. There it will perform multiple science missions until a planned deorbit on Ganymede by late 2035.

22 thoughts on “ESA Juice’s RIME Antenna Breaks Free After Some Jiggling And Percussive Action

  1. …but Ganymede already had a population in large glasshouses where they were growing food for the belt. Then the protomolecule man came along, and other baddies then destroyed the in-orbit floating mirrors.

    (Reference “The Expanse”)

  2. If there was something you could actuate “in the jammed bracket”, why wasn’t that the first thing you would try, as opposed to it being a “breakthrough”.

        1. My first foray into being a test engineer I got schooled on the term “percussive testing” which involved thumping the EUT with the butt-end of a screwdriver to see if anything stopped working.

    1. NEA 6, the actuator that released the antenna from the stuck pin was intended for the subsequent deployment stage. If you watch the video of the event and compare it with the animation of how it was supposed to deploy you’ll see the difference. It was not qualified to deploy like that, and as such, carries a certain amount of risk. This is why it was carried out only after attempting to dislodge it in such a way that it can continue to deploy nominally, using other means.

  3. I’m actually really glad to hear this worked. That’s a big accomplishment for something like this, where the investment is STEEP, the application is remote in the extreme, and the available solutions are extremely thin. That’s problem-solving in the style that can only be found in space exploration: one does what they can with what’s available, and God help you if you can’t. So you do. A lot of valuable information will come back because of somebody’s extremely high-pressure kludge. Congratulations to them.

  4. Probably could have programmed some part of it to pulse out “Shake it off’ to make it pop loose. Other possibilities would be “You shook me all night long” or “I want to break free”. Give it the Floppotron treatment.

  5. All these years I’ve been building actuators, when I could have been calling them “Non Explosive” actuators. Which sounds cooler, even if it’s just a normal actuator.

  6. Remote repairs of spacecrafts in general, esp. electrical…

    I’m wondering how are the design guides that allow this. I read about the power supply repair of voyager, they bypassed some voltage regulators, or Apollo problems which were solved by connecting bus bars to totally unplanned devices. I mean, is there something like a crossbar switch in the spacecraft that allows to connect anything with anything?

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