ESA’s Jupiter Icy Moons Explorer (Juice) Deploys Instruments: Latest Updates on Science & Exploration

Science & Exploration

26/05/2023
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Flight controllers at ESA’s mission control center in Germany have been busy this week, working with the instrument team on final deployment to prepare ESA’s Jupiter Icy Moons Explorer (Juice) to explore Jupiter.

It’s been six weeks since Juice began its journey, and in that time the Flight Control Team has deployed all of the solar panels, antennas, probes and booms that were safely stowed during launch. The final step is swings out and locks into place the probe and antenna that make up the Radio Wave & Plasma Investigation (RPWI) Juice.

“It’s been a grueling but very enjoyable six weeks,” said Angela Dietz, deputy spacecraft operations manager for the mission. “We have faced and overcome numerous challenges to get Juice in the right condition to get the best science from its journey to Jupiter.”

We get regular snapshots of the entire deployment process thanks to Juice’s two built-in monitoring cameras, each of which has a different field of view. Hours after launch, these cameras took Juice’s first ‘selfie’ from space, and since then, these cameras have been critical to checking that all the spacecraft’s parts were assembled correctly.

Juice’s antenna and boom each carry some or all of Juice’s 10 instruments. By placing it far from Juice, instruments that need to be separated from the spacecraft’s own electric and magnetic fields will be kept at a distance.

This suite of advanced instruments will collect data that helps us answer questions like: What are the oceans like on Jupiter? Why is Ganymede so unique? Could there be – or ever have been – life in the Jupiter system? How does Jupiter’s complex environment shape its moons, and vice versa? What do gas giant planets generally look like – how do they form and how do they work?

Accompanying our views from the monitoring cameras, confirmation that everything was going according to plan also came from the instruments themselves. The teams behind some of the instruments have turned them on and taken measurements to make sure everything is working properly. The team has confirmed that Juice’s RPWI, JANUS, J-MAG and GALA instruments, as well as the RADEM radiation monitor, are ready for Jupiter.

RPWI: five days, seven deployments

This week, four Langmuir Probes and three Radio Wave Instrument antennas from Radio & Plasma Wave Investigation (RPWI) were successfully deployed. These are seven of 10 RPWI sensors that will measure variations in the electric and magnetic fields around Jupiter, as well as radio waves and cold plasma.

Juice’s fourth Langmuir Probe was deployed, marking the completion of the deployment process

After seeing the final blast successfully carried out this afternoon, RPWI principal investigator Jan-Erik Wahlund from the Swedish Institute for Space Physics said: “Incredibly, after more than 10 years of intensive work, we are finally ready for a science discovery!”

RPWI will be the first device to produce a 3D map of the electric field around Jupiter. This will give us valuable information about how energy is transferred between Jupiter’s huge, rotating magnetosphere and the huge icy moons Ganymede, Callisto, and Europa. This energy transfer, for example, drives auroras on Ganymede and Jupiter’s upper atmosphere. RPWI’s special sensitivity to low frequencies means it will be able to detect very weak electromagnetic signals from tides and currents beneath the surface of the icy moons’ oceans.

Preliminary RPWI data

Before and after deployment, the RPWI team turned on instruments to measure the differences produced by each newly implemented sensor. Each now collects data and sends it to a data processing unit at RPWI, which then sends the data to Earth.

“Our 3D design strategy enables measurements of actual physical observations, such as energy and momentum, without using theory or simulations to interpret the data,” said Jan Bergman, researcher at the Swedish Institute for Space Physics and RPWI technical manager. .

For further details regarding the implementation of RPWI, see the Swedish National Space Agency website (scroll down for English).

JANUS: the first image taken in space

First image of JANUS: a star field in the constellation Cygnus

Last week, when Juice was about 8 million km from Earth, engineers turned on the JANUS optical camera instrument for the first time. Unlike the RPWI sensor which is mounted on a boom away from the Juice main body, the JANUS is mounted on an optical bench; this means it remains stable when aiming at its target – like using a tripod on Earth. JANUS also points in the same direction as Juice’s other ‘remote sensing’ instruments.

On Jupiter, the JANUS camera will take images in 13 different colors, from violet light to near infrared. These images will allow scientists to investigate the moons Ganymede, Callisto and Europa, including studying whether there is life beneath their icy crusts. JANUS will also collect data about other parts of Jupiter’s system, including intense volcanic activity on Io, its many smaller moons, and Jupiter’s faint ring system. Finally, JANUS will photograph the processes that occur in Jupiter’s atmosphere.

During commissioning last week, a thorough hardware check was carried out, with all subsystems activated and monitored. The instrument’s performance is checked by taking images of the stars.

“The data obtained shows that everything is nominal. After this intense field session, we can say: we have a (fully commissioned) instrument!” said Pasquale Palumbo (IAPS-INAF), JANUS principal investigator.

For more details see the website of the Italian National Institute of Astrophysics.

RIME: difficult situation, finally let go

The journey to full implementation has not been completely smooth. Just days after launch, flight controllers attempted to deploy the antenna of the Radar for Icy Moon Exploration (RIME) instrument. The first antenna segment opened as planned, but subsequent segments refused to budge.

RIME antenna deployment

The controller suspects that a small pin has become stuck causing the segment to become stuck in place. They put their minds together to find a solution. They shook Juice using the plunger. They warm the juice using sunlight. Every day the antenna shows signs of movement, but remains stuck to its bracket. Finally, RIME was snapped up almost three weeks later, when the team fired a mechanical device into the bracket. The shock moves the pin a few millimeters. To facilitate operations for ESA and the project team and industry, the antenna is completely open.

RIME trials are still ongoing, but the team has already made several measurements with the instrument.