The Jupiter mission takes the first destination images from Earth

As part of the preparations for launching Jupiter Icy Moons Explorer from ESA, ESA's navigation camera was subjected to a unique test: imaging its destination from the Earth.

JUICE, the explorer of Jupiter Icy Moons, will be launched in 2022 for a seven-year trip to the Jupiter system. In the framework of the first mission of this type, not only will it orbit Jupiter, but also Europe, Ganymede and Callisto, but it will end with a dedicated orbital visit of Ganymede, the largest moon in the world. System.

The spacecraft will be equipped with a suite of scientifically powerful instruments for in-depth analysis of Jupiter, its environment and its moons, but it will also use essential elements such as a navigation camera or NavCam. With the radio tracking, the NavCam will be used to get the position and speed of the probe relative to the moon by which it is flying.

The NavCam has been specifically designed to withstand the extreme radiation environments around Jupiter and to acquire images of the planet, moon and stars in the background. It is important to note that NavCam's measurements will allow the spacecraft to follow the optimal trajectory, consume as little fuel as possible during Jupiter's great turn, and improve pointing accuracy during these quick rendezvous approaches. and close together. The close encounters will bring the probe between 200 and 400 km until the moons.

In June, a team of engineers went to the roof of the Airbus Defense and Space site in Toulouse to test the NavCam engineering model in real-world conditions. The goal was to validate the hardware and software interfaces and prepare the image processing software and embedded navigation that will be used in flight for the acquisition of images.

In addition to observing the Moon of the Earth and other objects, the instrument was directed to an obvious target in the night sky: Jupiter. The camera used the "Imaging Mode" and the "Star Centroid Mode" to test the parameter settings, which will then be used to refine the image processing software at the control levels of the camera. the trim and navigation.

"Unsurprisingly, at some 640 million kilometers, Jupiter's moons are only perceived as a pixel or two, and Jupiter itself appears saturated in long-exposure images needed to capture both moons and stars backwards. but these images are useful for – adjusting our image processing software that will work autonomously aboard the spacecraft, "said Gregory Jonniaux, vision-based navigation expert at Airbus Defense and Space. "It seemed particularly useful to carry out our tests already on our destination!"

During the overflights themselves, it will be possible to see the characteristics of the surface on these very different moons. In a separate test, the NavCam was optically powered with simulated moons views to process more realistic images of what was expected once in the Jupiter system.

"The simulated views of Jupiter's moons give a more realistic impression of what our NavCam will capture during fly-bys," adds Daniele Gherardi, expert in guidance, navigation and control of ESA. "Of course, the suite of high resolution scientific cameras will impress us with even more detail on these enigmatic moons."

Meanwhile, the test navigation camera will be enhanced with a set of performance optics representative of the full flight by the end of the year and will subsequently be used to support the Embedded software tests of the entire JUICE spacecraft. After launch, the test camera will be used at the ESA Operations Center to support mission operations throughout its mission.

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