Juice to fly previous Earth for third gravity help

Getting a spacecraft to the outer Photo voltaic System isn’t any straightforward feat. Juice’s journey started nearly 3.5 years in the past, with its April 2023 launch from Europe’s Spaceport in French Guiana. Since then, flight controllers on Earth have efficiently guided it by the primary ever lunar-Earth flyby (a ‘braking’ manoeuvre to take Juice on a shortcut to Jupiter by way of Venus) after which a Venus flyby (that bent its orbit and gave it just a little additional velocity).

However there’s nonetheless an extended solution to go. To keep away from needing monumental quantities of gas to get it onto the fitting closing observe, Juice will make two additional flybys of Earth. On 28 September 2026, the spacecraft will come inside 8640 km of our planet. This interplay will set it up for a closing Earth flyby in January 2029, placing Juice onto the optimum path to intercept Jupiter in July 2031.

Subsequent week’s flyby will deflect the trajectory of the spacecraft by about 20 levels and enhance its velocity by about 3.5 km/s. The closest strategy will likely be over the Indian Ocean at 13:45 CEST (11:45 UTC).

Between 15 and half-hour earlier than closest strategy, Juice will move over Australia, travelling from the northeast of the nation to the northwest. Novice astronomers utilizing the fitting telescope or binocular gear might be able to observe it. Trajectory information could be discovered here.

Why does Juice want gravitational assist from the planets?

Why not simply fly straight to Jupiter after which brake exhausting after we get there? True, this may have been a lot faster. However it will have additionally required an unlimited rocket and an unthinkable quantity of gas to choose up sufficient velocity for the journey. After which an enormous quantity extra gas to stop Juice from flying straight previous Jupiter when it will get there.

As a substitute, flight controllers devised a intelligent technique to take advantage of the planets and their gravity. Because of Earth, the Moon and Venus, Juice is selecting up some velocity and adjusting its path in simply the fitting manner – nearly totally free of charge.

All because of this Juice could have loads of gas left in its tanks to enter orbit round Jupiter in 2031, after which big moon Ganymede in 2034.

Find out more about Juice’s complex journey to Jupiter.

How are we making sure the flyby is a success?

What our spacecraft operators call the ‘navigation campaign’ started on 17 August. Six timeslots were set aside – including at four weeks, two weeks, one week, and three days before the flyby – to make tiny corrections to Juice’s trajectory to ensure that it arrives with exactly the right angle and velocity for an optimum gravity assist.

“Until now, only one manoeuvre at minus four weeks was needed,” says Angela Dietz, Juice Spacecraft Operations Manager. “It was of relatively small size, but extremely effective. It put Juice in the right spot for the flyby. Our Flight Dynamics Team did an amazing job to prepare it!”

At 08:00 CEST on 28 September, flight controllers will be prepared to make a final emergency manoeuvre to fix critical navigation errors or avoid a collision with other satellites. All going well, this manoeuvre will not be needed.

This flyby comes with an additional challenge. Just before the closest approach, from 21:24 CEST on 27 September to 06:03 CEST on 28 September, Juice will be in Earth’s shadow. The lack of sunlight means that the spacecraft will be working on battery power alone. To avoid depleting its batteries completely, the team is prioritising the most important instrument observations with Juice’s science instruments during this time.

Bonus science

Just like during the 2024 lunar-Earth flyby, Juice’s 10 science instruments will be switched on to collect data on Earth and the Moon between 23 September and 3 October.

This provides a great opportunity for instrument teams to collect and analyse data from an actual surface in space. By calibrating their instruments and preparing data analysis tools now, teams will be ready to collect the best scientific data at Jupiter and its icy moons.

“All flybys are risky, requiring very careful planning and continuous monitoring. But the upcoming Earth flyby is much simpler from an operational perspective than the 2024 lunar-Earth flyby, where a flyby of the Moon set Juice up for a flyby of Earth the next day,” says Claire Vallat, Juice Project Scientist.

“This is great news for science, because it means we will be able to turn Juice in all different directions to point its science instruments at different parts of Earth and the Moon.”

One interesting scientific aspect of this flyby is that Juice will spend several days in the tail of Earth’s magnetic field. Stretched out away from the Sun like a windsock, this ‘magnetotail’ is a very complex structure created by charged particles flying towards us from the Sun. Juice is likely to get some very interesting magnetic field measurements that could later be combined with data from the European–Chinese Smile mission.

Meanwhile, Juice’s navigation camera – which will ultimately help the spacecraft steer around Jupiter’s moons – will take the opportunity to point towards the horizon of our own Moon. The images it takes will test out a new technique to improve the accuracy of its optical navigation.

Juice’s two onboard monitoring cameras will be snapping photos throughout the flyby, which we will be sharing via social media and the ESA website. Their last images of this event will be taken on 29 September.

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About Juice

ESA’s Jupiter Icy Moons Explorer, ‘Juice’, is humankind’s subsequent daring mission to the outer Photo voltaic System. It would make detailed observations of gasoline big Jupiter and its three massive ocean-bearing moons – Ganymede, Callisto and Europa. This formidable mission will characterise these moons with a robust suite of distant sensing, geophysical and in situ devices to find extra about these compelling locations as potential habitats for previous or current life.

Juice will monitor Jupiter’s advanced magnetic, radiation and plasma surroundings in depth and its interaction with the moons, finding out the Jupiter system as an archetype for gasoline big programs throughout the Universe.

Juice launched on an Ariane 5 from Europe’s Spaceport in Kourou in April 2023. It has an eight-year cruise with flybys of Earth and Venus to slingshot it to Jupiter. It would make 35 flybys of the three massive moons whereas orbiting Jupiter, earlier than altering orbits to Ganymede.

Juice is a mission underneath ESA management with contributions from NASA, JAXA and the Israel House Company. It’s the first Giant-class mission in ESA’s Cosmic Imaginative and prescient programme.

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