Juice burns exhausting in direction of first-ever Earth-Moon flyby

Mission to Jupiter picks up pace

ESA’s Jupiter Icy Moons Explorer (Juice) launched from Europe’s spaceport in French Guiana on 14 April 2023.

It’s on a mission to make detailed observations of the large fuel planet and its three massive, ocean-bearing moons – Ganymede, Callisto and Europa.

However Juice received’t start its investigations into the character and doable habitability of the Jupiter system till its arrival in 2031.

Why does it take so lengthy to get to Jupiter? Nicely, the brief reply is that its much less to do with the gap between Earth and Jupiter and extra to do with preventing the Solar’s large gravitational pull as you enterprise outwards by the Photo voltaic System.

Missions to the large fuel planets, comparable to Juice, Europa Clipper, Galileo or Juno, could be little greater than large gasoline tanks in the event that they needed to retailer all of the power wanted to beat the Solar’s gravity by themselves.

As an alternative, they make use of ‘gravity-assist’ or ‘flyby’ manoeuvres to achieve power by swinging by the sturdy gravitational fields of assorted planets on the best way.

Taking pictures for the Moon

Juice’s first enhance will come from its house planet, when it returns to Earth in August 2024, multiple yr after launch.

In actual fact, in a first-of-its-kind flyby, Juice will first cross by the Moon to present it an additional kick and make the flyby of Earth that takes place 1.5 days later much more efficient.

However even with this additional enhance, to get probably the most out of the gravity help, Juice has to reach on the Earth-Moon system at exactly the proper time, on the appropriate pace and travelling within the appropriate route.

That’s the place immediately’s manoeuvre is available in.

On 17 November, at 16:10 (CET), Juice’s principal engine carried out a burn that lasted roughly 43 minutes.

“This manoeuvre used up roughly 363 kg of gasoline – or virtually precisely 10% of the 3650kg of gasoline that Juice launched with,” says Julia Schwartz, Flight Dynamics Engineer at ESA’s ESOC mission management centre in Germany.

That is Juice’s largest manoeuvre thus far. Till immediately, Juice had solely used roughly 10 kg of gasoline – principally as a part of a collection of brief burns used to assist free its caught RIME antenna. 

“It was the primary a part of a two-part manoeuvre to place Juice on the proper trajectory for subsequent summer season’s encounter with Earth and the Moon. This primary burn did 95% of the work, altering Juice’s velocity by virtually 200 m/s,” provides Julia.

“Juice is among the heaviest interplanetary spacecraft ever launched, with a complete mass of round 6000 kg, so it took a whole lot of power and a whole lot of gasoline to realize this.”

“In a couple of weeks, as soon as we’ve analysed Juice’s new orbit, we’ll perform the second, a lot smaller second a part of the manoeuvre. Splitting the manoeuvre into two elements permits us to make use of the second firing of the engine to iron out any inaccuracies of the primary.”

A further, a lot smaller manoeuvre utilizing Juice’s smaller thrusters could also be carried out in Could 2024 for the ultimate wonderful tuning through the strategy to Earth.

Final use of the principle engine till 2031

For a mission on an eight-year journey, burning 10% of your gasoline reserve in simply 43 minutes could appear loopy. However investing all that gasoline now will repay for years to return.

“If all goes nicely with each elements of this manoeuvre, we seemingly received’t want to make use of the principle engine once more till we enter orbit round Jupiter in 2031,” says Ignacio Tanco, Juice Spacecraft Operations Supervisor. “For small trajectory corrections between every now and then, we’ll use Juice’s smaller thrusters.”

However that doesn’t imply nothing fascinating will occur between now and Juice’s arrival at Jupiter. Fairly the alternative, the journey is fascinating as a result of it permits Juice to get all the best way to Jupiter with out firing of its principal engine once more, lowering the quantity of gasoline the spacecraft wants and permitting it to be packed stuffed with scientific devices.

After the Earth-Moon double flyby of 2024 (is aware of as a Lunar-Earth Gravity Help; LEGA), Juice will first make one flyby of Venus in 2025 and two additional flybys of Earth in 2026 and 2029 (each with out the extra enhance from the Moon).

“Right now’s manoeuvre will guarantee Juice arrives on the Earth-Moon system on the proper time subsequent yr for the double flyby,” provides Ignacio.

“And, because of the intelligent trajectory designed by our Mission Analysis team, that flyby will line it up virtually completely for the entire others, with out us having to fireplace the principle engine once more.”

With every flyby, the spacecraft will acquire extra power than may very well be achieved by burning an affordable quantity of gasoline – power that can assist it climb in direction of Jupiter towards the pull of the Solar’s gravity.

“It was essential that we feature out this manoeuvre immediately. In any other case, the price – how a lot gasoline we would want to burn to succeed in the brand new orbit we want – would start to shoot up dramatically,” says Ignacio.

Right now’s burn additionally gave the groups the chance to ensure Juice’s principal engine is working accurately. It was first examined shortly after launch, however it till immediately, it hadn’t been used for such an enormous manoeuvre out in deep house.

“There have been some issues that we couldn’t take a look at prior to now. For instance, we solely had an estimate for a way the liquid within the gasoline tanks will transfer round because the spacecraft accelerates. This is essential to know exactly, as a result of if the gasoline behaves completely different to how we count on, it might trigger the spacecraft to float off target through the burn. So, we’re monitoring carefully.”

Subsequent cease: Jupiter!

The subsequent time that Juice will completely have to fireplace its principal engine is throughout its ‘Jupiter Orbit Insertion’ in 2031. That is the one most necessary manoeuvre that the groups at ESOC will oversee.

Simply 13 hours after swinging by Ganymede and coming into the Jupiter system, the spacecraft might want to decelerate by about 1 km/s – 5 instances the change in velocity achieved immediately.

“That makes immediately’s manoeuvre additionally an necessary take a look at for Jupiter insertion – the earlier we all know if we have now any points with the principle engine, the higher,” says Ignacio.

As soon as in orbit across the fuel large, Juice can start its exploration of the Jupiter system. Groups at ESOC will steer Juice by a collection of 35 flybys of the ocean moons. The place as soon as flybys had been a yearly prevalence, at Jupiter they are going to be carried out as usually as as soon as each two weeks.

These close-ups of the icy moons will permit the spacecraft and scientists on Earth to assemble the info wanted to raised perceive these mysterious alien worlds.

Juice – updated and behind the scenes

Wish to know extra about how Juice was imagined, designed, constructed and launched? The feature-length movie, ‘The Making of Juice’, premieres on ESA’s YouTube channel at 18:00 CET on 23 November 2023.

For normal updates on the mission, observe @ESA_JUICE, @esaoperations and @ESAJuiceBar on X.