ESA’s Juice spacecraft carried out a important maneuver to align for an Earth-Moon gravity help in 2024, a part of its eight-year mission to Jupiter. The maneuver is a key step in a fuel-efficient trajectory that features additional planetary flybys, aiming to review Jupiter’s moons upon arrival in 2031. This illustration depicts ESA’s Jupiter Icy Moons Explorer (JUICE) approaching Earth. Credit score: ESA/Lightcurve Movies/R. Andres
On November 17, 2023, ESA’s Juice spacecraft carried out one of many largest and most necessary maneuvers in its eight-year journey to Jupiter.
Utilizing its primary engine, Juice modified its orbit across the Solar to place itself on the proper trajectory for subsequent summer time’s Earth-Moon double gravity help – the primary of its variety.
The maneuver lasted 43 minutes and burned nearly 10% of the spacecraft’s complete gas reserve. It’s the primary a part of a two-part maneuver that might mark the ultimate time that Juice’s primary engine is used till its arrival within the Jupiter system in 2031.
Mission to Jupiter Picks Up Pace
ESA’s Jupiter Icy Moons Explorer (Juice) launched from Europe’s spaceport in French Guiana on April 14, 2023.
It’s on a mission to make detailed observations of the large gasoline planet and its three giant, ocean-bearing moons – Ganymede, Callisto, and Europa.
However Juice gained’t start its investigations into the character and doable habitability of the Jupiter system till its arrival in 2031.
Propulsion: lift-off, orbit changes, and touring by way of area Credit score: ESA/S. Berna
Why does it take so lengthy to get to Jupiter? Nicely, the brief reply is that it has much less to do with the space between Earth and Jupiter and extra to do with preventing the Solar’s huge gravitational pull as you enterprise outwards by way of the Photo voltaic System.
Missions to the large gasoline planets, resembling Juice, Europa Clipper, Galileo, or Juno, could be little greater than large gas tanks in the event that they needed to retailer all of the vitality wanted to beat the Solar’s gravity by themselves.
As an alternative, they make use of ‘gravity-assist’ or ‘flyby’ maneuvers to achieve vitality by swinging by way of the robust gravitational fields of assorted planets on the way in which.
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.
The truth is, in a first-of-its-kind flyby, Juice will first move 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.
Simulation of Juice’s Lunar-Earth Gravity Help. Credit score: ESA/Lightcurve Movies/R. Andres
However even with this further 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 right velocity, and touring within the right course.
That’s the place immediately’s maneuver is available in.
On November 17, at 16:10 (CET), Juice’s primary engine carried out a burn that lasted roughly 43 minutes.
“This maneuver used up roughly 363 kg of gas – or nearly precisely 10% of the 3650kg of gas that Juice launched with,” says Julia Schwartz, Flight Dynamics Engineer at ESA’s ESOC mission management heart in Germany.
That is Juice’s largest manoeuvre thus far. Till immediately, Juice had solely used roughly 10 kg of gas – 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 maneuver to place Juice on the proper trajectory for subsequent summer time’s encounter with Earth and the Moon. This primary burn did 95% of the work, altering Juice’s velocity by nearly 200 m/s,” provides Julia.
“Juice is without doubt one of the heaviest interplanetary spacecraft ever launched, with a complete mass of round 6000 kg, so it took quite a lot of pressure and quite a lot of gas to attain this.”
“In a couple of weeks, as soon as we’ve analyzed Juice’s new orbit, we are going to perform the second, a lot smaller second a part of the maneuver. Splitting the maneuver 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 maneuver utilizing Juice’s smaller thrusters could also be carried out in Might 2024 for the ultimate fine-tuning through the strategy to Earth.
Juice maneuver strains it up for the 2024 Earth-Moon flyby. Credit score: ESA
Final use of the principle engine till 2031
For a mission on an eight-year journey, burning 10% of your gas reserve in simply 43 minutes could appear loopy. However investing all that gas now will repay for years to come back.
“If all goes nicely with each elements of this maneuver, we probably gained’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 are going to use Juice’s smaller thrusters.”
However that doesn’t imply nothing attention-grabbing will occur between now and Juice’s arrival at Jupiter. Fairly the alternative, the journey is attention-grabbing as a result of it permits Juice to get all the way in which to Jupiter with out firing of its primary engine once more, lowering the quantity of gas the spacecraft wants and permitting it to be packed stuffed with scientific devices.
Juice will begin its science mission about six months previous to coming into orbit round Jupiter in 2031, making observations because it approaches its vacation spot. It makes a primary flyby of Ganymede a couple of hours earlier than Jupiter orbit insertion. As soon as within the Jovian system and in orbit round Jupiter, a collection of additional gravity-assist flybys Ganymede will assist Juice cut back its orbital vitality as wanted. Credit score: ESA/Lightcurve Movies/R. Andres
After the Earth-Moon double flyby of 2024 (referred to 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).
“Immediately’s maneuver will guarantee Juice arrives on the Earth-Moon system on the proper time subsequent yr for the double flyby,” provides Ignacio.
“And, due to the intelligent trajectory designed by our Mission Evaluation workforce, that flyby will line it up nearly completely for the entire others, with out us having to fireplace the principle engine once more.”
With every flyby, the spacecraft will acquire extra vitality than may very well be achieved by burning an affordable quantity of gas – vitality that can assist it climb in the direction of Jupiter in opposition to the pull of the Solar’s gravity.
On its journey to Jupiter, Juice will make a collection of flybys of Earth, the Earth-Moon system and Venus to set it on the right track for its July 2031 rendezvous within the Jovian system.
Juice will make three Earth flybys throughout its cruise: one of many Earth-Moon system in August 2024, considered one of Earth in September 2026, and as soon as once more considered one of Earth in January 2029.
In complete Juice will spend roughly eight years cruising to Jupiter. It would attain Jupiter in July 2031, however will already start making scientific observations six months earlier than coming into orbit round Jupiter. Juice will go on to spend many months orbiting Jupiter, making 35 flybys of icy moons Europa, Ganymede, and Callisto, and at last conducting an orbital tour of Ganymede.
Credit score: ESA
“It was essential that we supply out this maneuver immediately. In any other case, the fee – how a lot gas we would want to burn to achieve the brand new orbit we want – would start to shoot up dramatically,” says Ignacio.
Immediately’s burn additionally gave the groups the chance to verify Juice’s primary engine is working accurately. It was first examined shortly after launch, but it surely till immediately, it hadn’t been used for such an enormous maneuver out in deep area.
“There have been some issues that we couldn’t take a look at prior to now. For instance, we solely had an estimate for the way the liquid within the gas tanks will transfer round because the spacecraft accelerates. This is essential to know exactly, as a result of if the gas behaves otherwise to how we count on, it might trigger the spacecraft to float off target through the burn. So, we’re monitoring intently.”
Artist’s impression of the Juice mission exploring the Jupiter system. Credit score: spacecraft: ESA/ATG medialab; Jupiter: NASA/ESA/J. Nichols (College of Leicester); Ganymede: NASA/JPL; Io: NASA/JPL/College of Arizona; Callisto and Europa: NASA/JPL/DLR
Subsequent Cease: Jupiter!
The following time that Juice will completely have to fireplace its primary engine is throughout its ‘Jupiter Orbit Insertion’ in 2031. That is the one most necessary maneuver 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 occasions the change in velocity achieved immediately.
“That makes immediately’s maneuver additionally an necessary take a look at for Jupiter insertion – the earlier we all know if we now have any points with the principle engine, the higher,” says Ignacio.
As soon as in orbit across the gasoline large, Juice can start its exploration of the Jupiter system. Groups at ESOC will steer Juice by way of a collection of 35 flybys of the ocean moons. The place as soon as flybys have been a yearly prevalence, at Jupiter they are going to be carried out as typically as as soon as each two weeks.
These close-ups of the icy moons will enable the spacecraft and scientists on Earth to collect the info wanted to higher perceive these mysterious alien worlds.
