Suspecting ice formation as the concern, they heated up the spacecraft by sun direct exposure, however when this didnt work, they continued with the prepared antenna release, which ultimately removed the stuck pin and effectively deployed the antenna. Juices stuck but moving RIME antenna is caught by the Juice Monitoring Camera on board the spacecraft. Given that there are no heating units on the spacecraft near RIME, eliminating the ice would imply turning the spacecraft so that the antenna faced the Sun. And so it ended up being obvious that the only possibility to recuperate the antenna was to heat the antenna again, and then continue with the implementation in the hopes that the shocks from the other NEAs would unjam the pin. To recreate the conditions of that lab as closely as possible, the group took the choice to rotate the spacecraft, moving the antenna away from the Sun, and wait for three to 4 hours for its temperature to drop.
Juices RIME antenna, folded prepared for release. ESAs Jupiter Icy Moons Explorer, Juice, captured this image with its Juice keeping an eye on video camera 2 (JMC2) quickly after launch on April 14, 2023. Credit: ESA/Juice/JMC
To be successful in collecting this data, scientists had to initially get the spacecraft and its instruments into area– and that implied folding up some of the hardware.
At 16 m in length, the RIME antenna was too long to fit inside the nose cone of the Ariane 5 rocket that launched Juice into space. It was therefore built in two booms of four sectors each. Of those 8 sectors, three would release on one side of the spacecraft, three on the other side, and two would remain fixed on the spacecraft. For launch, the 3 deployable sections were folded back onto the fixed segment and kept in place by 2 brackets.
Once in space, gadgets called non-explosive actuators (NEAs) would be from another location activated one after the other from the European Space Operations Centre (ESOC), Darmstadt, Germany. Each NEA would remove a holding pin from its bracket, enabling that section to spring into location.
Whichs where the problems started.
The treatment to release Juices RIME antenna started on April 17, 2023, 3 days after the launch, and with whatever having proceeded smoothly up till that point. From the downloads, the antenna sector was noticeable on one image, and then not on the next. In between the images, the NEA had actually fired, the pin had actually launched and the antenna sector had actually snapped into place.
Ronan Le Letty, Senior Mechanisms Engineer for ESA and part of the Juice group, was at ESOC throughout the RIME release, encouraging the flight control group who were receiving telemetry from the spacecrafts various onboard sensors and sending out Juice commands.
The treatment began on April 17, 2023, 3 days after the launch and with whatever having continued efficiently up till that point.
Two monitoring video cameras, installed onboard the spacecraft, were used to follow the RIME deployment. From the downloads, the antenna sector was visible on one image, and then not on the next. In in between the images, the NEA had fired, the pin had released and the antenna segment had actually snapped into location.
Pleased, the team moved on to the second segment.
The command was offered to fire the actuator. The telemetry got here before the images, but something was wrong. The expected oscillation was not revealing. A few seconds later on, the cam image returned. The boom segment was still clearly visible in its stowed configuration. The implementation had actually stopped working.
” You experience a state of disbelief,” states Ronan, “The most unwanted situation is taking place. We examined the picture 2, three, four times. We attempted again to activate the actuator, but absolutely nothing occurred.”
Juices stuck but moving RIME antenna is caught by the Juice Monitoring Camera on board the spacecraft. This animation shows the radars movements in 5 photos taken throughout April 17– 21, as groups in the world overcome actions in Juices release. Credit: ESA/Juice/JMC
Also viewing in a state of professional shock was the team at Airbus Defence and Space, Toulouse, France. Chosen as the spacecrafts prime contractor in 2015, they were accountable for leading the style, building and construction, and testing of the spacecraft and generating other companies to provide components, systems and instruments as required.
” We knew that we needed to quickly attempt to comprehend what had happened, and then search for a workaround,” states Frédéric Faye, Airbuss primary engineer for Juice.
The really next morning, with the disbelief banished from their minds, the groups collected online for a teleconference to share their insights and talk about the abnormality. On one hand, they knew they needed to find some method to release the stuck sector, however on the other, they knew that they could not do anything that would compromise the release of the other sections, or indeed the remainder of the spacecraft.
The very first idea that struck the teams was that maybe some ice had actually formed on the pin holding the section in place. Every time a spacecraft leaves Earth, it finds itself in a cold, airless environment. This significant and sudden loss of atmospheric pressure suggests that a percentage of water vapor will all of a sudden leave from the product utilized to make the craft. This can then freeze onto the exceptionally cold surfaces of the spacecraft.
Since there are no heaters on the spacecraft near RIME, eliminating the ice would suggest rotating the spacecraft so that the antenna faced the Sun. The surface area of the spacecraft holding RIME was designed to be a cold face, implying that it was never ever meant to be exposed to the direct sunlight just after launch. Nor were the parts, instruments and systems that were connected to it.
After numerous days of research study, the team began slowly slewing the spacecraft so that the surface area was lit up. “We did 8 varieties over two weeks to light up the RIME bracket,” states Angela Dietz, Spacecraft Operations Manager at ESOC.
Simultaneously, other possible healing scenarios were being considered.
If it were not ice holding RIME shut, and the pin had simply stuck, then possibly shaking the spacecraft would jog it loose– although the word shaking is too severe to explain the real motion.
The spacecraft weighs six tonnes and the thrusters onboard can just rock it back and forth extremely gently. They could not risk hurting anything else with a violent shock of the spacecraft.
” We did a number of thruster shootings and used the main engine, often related to the heating up varieties. The thrusters were even fired in a particular sequence to attempt to get rid of the stacked boom, however we just saw little motions within the bracket,” states Angela.
And so the team moved on to other concepts.
The manufacturer of the antenna, German company SpaceTech, also proposed a recovery plan. Efficiently, it was to continue deploying the other 4 sections of the antenna as if absolutely nothing had happened. They understood that as each NEA fired, it would produce a little mechanical shock in the rest of the antenna that could dislodge the stuck pin.
Then, the maker made a breakthrough. The engineers at SpaceTech handled to reproduce the anomaly with a model of the antenna that had actually been utilized for screening and verified that the firing of the closest NEA normally handled to remove the stuck pin. It was likewise determined that to increase the chances of a successful result, the antenna needs to be heated by exposure to sunshine.
This was since although the engineering design had been fully evaluated at the cold temperature levels of space, the real flight model had not. The team concluded that the incredibly cold conditions come across throughout the stopped working NEA release may have been a contributing element, therefore the antenna needs to be warmed by the Sun before all future actuations to get it as near space temperature as possible, where they understood it worked.
Equipped with numerous concepts for how to recover the instrument, the groups chose to meet face to face to choose the method forward. At a technical workshop held at SpaceTech, the teams chose to try the heating. If that did not work, they would proceed with shooting the other NEAs, having warmed them first with sunshine. “This workout to put down a plan and get all the groups working towards it was actually advantageous,” states Ronan.
It was now numerous weeks considering that the abnormality had actually happened and pressure was installing. The mission had a schedule to keep and as essential as RIME is, it was only one instrument on the spacecraft. “To me this was the most complex thing throughout the healing,” states Guillaume Chambon of Airbuss Technical Authority Team. Guillaume was placed in charge of handling the Airbus side of the recovery. “You have to be quickly enough to act because everybody is expecting you to make progress, however you need to take enough time to think about all the adverse effects of what you are proposing,” he states.
One afternoon, while pondering the rescue attempt, Guillaume did indeed realize a potential problem. There was a chance that two segments of the antenna could collide if they went ahead with the nominal release series.
On May 12 RIME was finally jolted into life when the flight control team fired a mechanical device called a non-explosive actuator (NEA), located in the jammed bracket. This delivered a shock that moved the pin by a matter of millimeters and enabled the antenna to unfold. Credit: ESA/Juice/JMC
Remember that the RIME antenna is made up of six deploying segments, 3 on each side of the spacecraft. In the small implementation circumstance, an NEA would be fired first on one side of the antenna and after that on the other. If they did this now, and the stuck area came totally free, then the 2 sides of the antenna would be deploying together in opposite instructions and might collide.
The groups concurred to reorder the implementation series, and the healing efforts began. First, the spacecraft was warmed to drive off any ice, but the antenna remained repaired.
Therefore it ended up being apparent that the only possibility to recover the antenna was to warm the antenna again, and then continue with the implementation in the hopes that the shocks from the other NEAs would unjam the pin. Once, their analysis had actually shown them that this would offer the best possibility of success however each NEA might just be fired. Simply put, it was all or absolutely nothing.
On May 12 RIME was finally jolted into life when the flight control group fired a mechanical device called a non-explosive actuator (NEA), located in the jammed bracket. This delivered a shock that moved the pin by a matter of millimeters and allowed the antenna to unfold. Credit: ESA/Juice/JMC, CC BY-SA 3.0 IGO
The command was sent and the groups saw the telemetry for any hint of an oscillation that would show success. There it was: movement on the spacecraft.
When the camera downloaded, the image showed them whatever they required to know.
Total success. The 3 sectors of the antenna that must be released, were deployed. “In the operations team we ended up being quietly positive,” says Angela.
One other NEA still required to be fired to deploy the second boom before RIME could presume its final operating setup. And if anything, the pressure felt by some on the group was even higher than previously because now the group knew that it was possible for the pins to jam.
If any of the previous ones had actually jammed, the group could have fired the next in series and hoped that the shock would finish the job– as it had on the initial stuck section. Now, there were no more NEAs to fire. At the surface line, they could still be beat if the pin jammed.
Juice objective operators commemorating the successful release of another instrument, RPWI. Credit: ESA
It was at this point that Cyril Cavel, the Juice job manager for Airbus found himself thinking about the scientists who were depending on them. Some had even been working on the antenna for decades. “RIME was a commercial delivery to these people. Without this antenna, the radar experiment would be either really lowered or even dead. It would be far more than simply a pity,” he states.
The opportunity to genuinely learn what was below the icy surface areas of those bewitching moons could have been considerably lessened or even lost for the existing generation of planetary scientists.
” We knew that, despite the fact that the RIME was one instrument out of ten, a failure to fully open the antenna would have degraded the clinical performance of the mission and compromised the– until that minute– outstanding picture of Juice and ESA to the external world,” states Giuseppe Sarri, ESAs Juice Project Manager.
As a result, the team took one final safety measure. By now, the last bracket had remained in sunshine for its optimum permitted time that day of 73 minutes. As a result, its temperature was higher than the ambient temperature level at which it had actually been checked in the laboratories in Germany. To replicate the conditions of that lab as carefully as possible, the team took the decision to rotate the spacecraft, moving the antenna away from the Sun, and await three to four hours for its temperature to drop.
” Those three to 4 hours were long,” states Frédéric.
At the end of the wait, when the conditions were right, the command was sent out.
The NEA activated, the telemetry showed Juice oscillating as the last sector deployed, the AOCS cut in and stabilised the spacecraft. Lastly, the cams validated the groups success, RIME was now in its totally deployed configuration.
For Ronan, the relief at seeing the implementation was tinged with a familiar sense of disbelief. I couldnt quite believe it, despite seeing the photos,” he states.
” When RIME was eventually launched I might almost see tears in the eyes of my associates,” states Giuseppe, before including, “But we were favorable from the start and the Champagne was already in the fridge …”.
When the bubbly was intoxicated and the team appropriately rested, the flight controllers at ESOC proceeded to the other deployments essential on the spacecraft, all of which have actually now been finished successfully. And the RIME anomaly teams at ESA, Airbus and SpaceTech, are simply covering up their understanding of the initial cause so that it can be avoided in the future on comparable systems.
As soon as again on a path to complete success, and the Juice objective itself is.
After the Radar for Icy Moon Exploration (RIME) antenna on ESAs Juice objective encountered deployment problems post-launch, combined efforts from engineers at ESA, Airbus, and SpaceTech effectively rectified the problem. Believing ice development as the problem, they heated up the spacecraft by sun exposure, but when this didnt work, they continued with the planned antenna deployment, which ultimately removed the stuck pin and successfully released the antenna. (Juice flyby of Ganymede, artists impression.) Credit: ESA
When the RIME antenna on ESAs Juice mission stopped working to release a couple of days after launch, the engineering groups dealt with the magnificent challenge to understand the fault and remedy it. At stake was a chance to see inside Jupiters strange icy moons.
The stakes were already high before the spacecraft ever left the ground. ESAs Jupiter Icy Moons Explorer (Juice) was developed by Airbus to conduct an extraordinary investigation of the Jupiter system and its family of icy moons.
A key to that investigation is the Radar for Icy Moon Exploration (RIME) antenna, which is part of Juices detailed suite of 10 science instruments. When in the Jupiter system, RIME will be utilized to from another location probe the subsurface of Jupiters icy moons.
