On 17 November 2023, ESA’s Juice spacecraft carried out one of many largest and most vital manoeuvres in its eight-year journey to Jupiter.
Utilizing its fundamental engine, Juice modified its orbit across the Solar to place itself on the right trajectory for subsequent summer time’s Earth-Moon double gravity help – the primary of its sort.
The manoeuvre lasted 43 minutes and burned nearly 10% of the spacecraft’s total gasoline reserve. It’s the primary a part of a two-part manoeuvre that would mark the ultimate time that Juice’s fundamental 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 14 April 2023.
It’s on a mission to make detailed observations of the enormous gasoline planet and its three giant, ocean-bearing moons – Ganymede, Callisto and Europa.
However Juice received’t start its investigations into the character and attainable habitability of the Jupiter system till its arrival in 2031.
Why does it take so lengthy to get to Jupiter? Effectively, the brief reply is that its much less to do with the space between Earth and Jupiter and extra to do with combating the Solar’s huge gravitational pull as you enterprise outwards via the Photo voltaic System.
Missions to the enormous gasoline planets, resembling 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 vitality wanted to beat the Solar’s gravity by themselves.
As a substitute, they make use of ‘gravity-assist’ or ‘flyby’ manoeuvres to realize vitality by swinging via the robust gravitational fields of assorted planets on the best way.
Taking pictures for the Moon
Juice’s first enhance will come from its dwelling planet, when it returns to Earth in August 2024, multiple 12 months 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 essentially the most out of the gravity help, Juice has to reach on the Earth-Moon system at exactly the right time, on the right pace and travelling within the right path.
That’s the place at this time’s manoeuvre is available in.
On 17 November, at 16:10 (CET), Juice’s fundamental engine carried out a burn that lasted roughly 43 minutes.
“This manoeuvre used up roughly 363 kg of gasoline – or nearly 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 to this point. Till at this time, Juice had solely used roughly 10 kg of gasoline – largely 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 right 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 numerous power and numerous gasoline to attain this.”
“In just a few weeks, as soon as we’ve analysed Juice’s new orbit, we are going to perform the second, a lot smaller second a part of the manoeuvre. Splitting the manoeuvre into two components 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 Might 2024 for the ultimate high quality tuning through the method to Earth.
Final use of the primary 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 effectively with each components of this manoeuvre, we probably received’t want to make use of the primary engine once more till we enter orbit round Jupiter in 2031,” says Ignacio Tanco, Juice Spacecraft Operations Supervisor. “For small trajectory corrections between at times, 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 best way to Jupiter with out firing of its fundamental engine once more, decreasing the quantity of gasoline the spacecraft wants and permitting it to be packed filled 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 this moment’s manoeuvre will guarantee Juice arrives on the Earth-Moon system on the proper time subsequent 12 months for the double flyby,” provides Ignacio.
“And, due to the intelligent trajectory designed by our Mission Evaluation crew, that flyby will line it up nearly completely for the entire others, with out us having to fireside the primary engine once more.”
With every flyby, the spacecraft will achieve extra vitality than might be achieved by burning an affordable quantity of gasoline – vitality that can assist it climb in direction of Jupiter in opposition to the pull of the Solar’s gravity.
“It was essential that we stock out this manoeuvre at this time. In any other case, the price – how a lot gasoline we would wish to burn to achieve the brand new orbit we want – would start to shoot up dramatically,” says Ignacio.
Right this moment’s burn additionally gave the groups the chance to verify Juice’s fundamental engine is working accurately. It was first examined shortly after launch, but it surely till at this time, it hadn’t been used for such a giant manoeuvre out in deep area.
“There have been some issues that we couldn’t check 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 may trigger the spacecraft to float off beam through the burn. So, we’re monitoring carefully.”
Subsequent cease: Jupiter!
The subsequent time that Juice will completely have to fireside its fundamental engine is throughout its ‘Jupiter Orbit Insertion’ in 2031. That is the one most vital manoeuvre that the groups at ESOC will oversee.
Simply 13 hours after swinging by Ganymede and getting into the Jupiter system, the spacecraft might want to decelerate by about 1 km/s – 5 occasions the change in velocity achieved at this time.
“That makes at this time’s manoeuvre additionally an vital check for Jupiter insertion – the earlier we all know if we now have any points with the primary 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 via a collection of 35 flybys of the ocean moons. The place as soon as flybys had been a yearly incidence, 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 enable the spacecraft and scientists on Earth to collect the info wanted to raised perceive these mysterious alien worlds.
Juice – updated and behind the scenes
Need 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.