By 2023,the mission was estimated to cost ESA 1.5 billion euros ($1.6 billion).[15]
Spacecraft
Juice inside Airbus Defence and Space Astrolabe facilities,2023
The main spacecraft design drivers are related to the large distance to the Sun,the use of solar power,and Jupiter's harsh radiation environment. The orbit insertions at Jupiter and Ganymede and the large number of flyby manoeuvres (more than 25 gravity assists,and two Europa flybys) require the spacecraft to carry about 3,000kg (6,600lb) of chemical propellant.[16] The total delta-V capability of the spacecraft is about 2,700m/s (6,000mph).[17]
Juice has a fixed 2.5 meter diameter high-gain antenna and a steerable medium-gain antenna,both X- and K-band will be used. Downlink rates of 2 Gb/day are possible with ground-based Deep Space Antennas. On-board data storage capability is 1.25 Tb.[1]
The Juice main engine is a hypergolic bi-propellant (mono-methyl hydrazine and mixed oxides of nitrogen) 425 N thruster. A 100 kg multilayer insulation provides thermal control. The spacecraft is 3-axis stabilized using momentum wheels. Radiation shielding is used to protect onboard electronics from the Jovian environment[1] (the required radiation tolerance is 50 kilorad at equipment level[17]).
The Juice science payload has a mass of 280 kilograms (620lb) and includes the JANUS camera system,the MAJIS visible and infrared imaging spectrometer,the UVS ultraviolet imaging spectrograph,RIME radar sounder,GALA laser altimeter,SWI submillimetre wave instrument,J-MAG magnetometer,PEP particle and plasma package,RPWI radio and plasma wave investigation,3GM radio science package,the PRIDE radio science instrument,and the RADEM radiation monitor. A 10.6 meters (35ft) deployable boom will hold J-MAG and RPWI,a 16 meters (52ft) long deployable antenna will be used for RIME. Four 3 meters (9.8ft) booms carry parts of the RPWI instrument. The other instruments are mounted on the spacecraft body,or for 3GM,within the spacecraft bus.[1]
The launch was originally scheduled for 13 April 2023,but due to poor weather the launch was postponed.[20] The next day a second launch attempt succeeded,with liftoff occurring at 12:14:36 UTC. After the spacecraft separated from the rocket,it established a successful radio signal connection with the ground at 13:04 UTC. Juice's solar arrays were deployed about half an hour later,prompting ESA to deem the launch a success.[18]
Trajectory
Following the launch,there will be multiple planned gravity assists to put Juice on a trajectory to Jupiter:[8]
A flyby of the Earth–Moon system in August 2024
Venus flyby in August 2025
Second flyby of Earth in September 2026
A third and final flyby of Earth in January 2029
Juice will pass through the asteroid belt twice. A flyby of the asteroid 223 Rosa was proposed to occur in October 2029,but was abandoned to save fuel for the primary Jovian mission.[21][22][23]
The main characteristics of the Jupiter reference tour are summarised below (source: Table 5-2 of ESA/SRE(2014)1[17]). This scenario assumed an early June 2022 launch, however, the delta-V requirements are representative due to the rather short, repetitive orbital configurations of Europa, Ganymede and Callisto.
When it arrives in the Jovian system in July 2031,[8] Juice will first perform a 400km (250mi) Ganymede gravity assist flyby to reduce spacecraft velocity by ~300m/s (670mph), followed by ~900m/s (2,000mph) Jupiter orbit insertion engine burn ~7.5 hours later. Finally, a Perijove Raising Manoeuvre (PRM) burn at apoapsis will raise the periapsis of Juice's initial 13x243 Jovian radii elongated orbit to match that of Ganymede (15 Rj).
186 days
952m/s (2,130mph).
2nd Ganymede flyby to initial encounter with Callisto: 2nd, 3rd and 4th Ganymede flyby to reduce the orbital period and inclination of Juice's orbit, followed by 1st flyby of Callisto.
193 days
27m/s (60mph).
Europa phase: Starting in July 2032,[8] there will be two <400km (250mi) flybys of Europa followed by another Callisto flyby. The brief Europa encounters (during which the probe is expected to sustain a third of its lifetime radiation exposure[25]) are planned such that the radiation exposure is as low as possible, first by encountering Europa at perijove (i.e. the spacecraft's perijove is equal to Europa’s orbital radius), and second by having only one low perijove passage per Europa flyby.
35 days
30m/s (67mph).
Inclined phase: ~6 further flybys of Callisto and Ganymede to temporarily increase the orbital inclination to 22 degrees. This will allow an investigation of Jupiter's polar regions and Jupiter's magnetosphere[8] at the maximum inclination over a four-month period.
208 days
13m/s (29mph).
Transfer to Ganymede: A series of Callisto and Ganymede gravity assists will be performed to gradually reduce Juice's speed by 1,600m/s (3,600mph). Finally, a series of distant ~45,000km (28,000mi) flybys of the far side of Ganymede (near the Jupiter-Ganymede-L2 Lagrange point) will further reduce the required orbital insertion delta-V by 500m/s (1,100mph).
353 days
60m/s (130mph).
Ganymede orbital phase: In December 2034,[8] Juice will enter an initial 12-hour polar orbit around Ganymede after performing a 185m/s (410mph) delta-V braking burn. Jupiter gravitational perturbations will gradually reduce the minimum orbital altitude to 500km (310mi) after ~100 days. The spacecraft will then perform two major engine firings to enter a nearly circular 500km (310mi) polar orbit, for a further six months of observations (e.g. Ganymede's composition and magnetosphere). At the end of 2035,[8] Jupiter perturbations will cause Juice to impact onto Ganymede within weeks as the spacecraft runs out of propellant.
284 days
614m/s (1,370mph).
Full tour (Jupiter orbit insertion to end of mission)
1259 days
1,696m/s (3,790mph).
Science objectives
Ganymede view by the Galileo spacecraftSection of Europa's icy surface, viewed from Galileo
For Europa, the focus is on the chemistry essential to life, including organic molecules, and on understanding the formation of surface features and the composition of the non-water-ice material. Furthermore, Juice will provide the first subsurface sounding of the moon, including the first determination of the minimal thickness of the icy crust over the most recently volcanically-active regions.
More distant spatially resolved observations will also be carried out for several minor irregular satellites and the volcanically active moon Io.
Science instruments
Juice instrumentsTesting a 1:18 scale model of Juice's RIME antenna in the Hertz facility, 2023
On 21 February 2013, after a competition, 11 science instruments were selected by ESA, which were developed by science and engineering teams from all over Europe, with participation from the US.[27][28][29][30] Japan also contributed several components for SWI, RPWI, GALA, PEP, JANUS and J-MAG instruments, and will facilitate testing.[31][32][33]
Jovis, Amorum ac Natorum Undique Scrutator (JANUS)
The name is Latin for "comprehensive observation of Jupiter, his love affairs and descendants."[34] It is a camera system to image Ganymede and interesting parts of the surface of Callisto at better than 400 m/pixel (resolution limited by mission data volume). Selected targets will be investigated in high-resolution with a spatial resolution from 25 m/pixel down to 2.4 m/pixel with a 1.3° field of view. The camera system has 13 panchromatic, broad and narrow-band filters in the 0.36μm to 1.1μm range, and provides stereo imaging capabilities. JANUS will also allow relating spectral, laser and radar measurements to geomorphology and thus will provide the overall geological context.
Moons and Jupiter Imaging Spectrometer (MAJIS[35])
A visible and infrared imaging spectrograph operating from 0.5μm to 5.56μm, with spectral resolution of 3–7nm, that will observe tropospheric cloud features and minor gas species on Jupiter and will investigate the composition of ices and minerals on the surfaces of the icy moons. The spatial resolution will be down to 75m (246ft) on Ganymede and about 100km (62mi) on Jupiter.
UV Imaging Spectrograph (UVS)
An imaging spectrograph operating in the wavelength range 55–210nm with spectral resolution of <0.6nm that will characterise exospheres and aurorae of the icy moons, including plume searches on Europa, and study the Jovian upper atmosphere and aurorae. Resolution up to 500m (1,600ft) observing Ganymede and up to 250km (160mi) observing Jupiter.
Sub-millimeter Wave Instrument (SWI)
A spectrometer using a 30cm (12in) antenna and working in 1080–1275 GHz and 530–601GHz with spectral resolving power of ~107 that will study Jupiter's stratosphere and troposphere, and the exospheres and surfaces of the icy moons.
Ganymede Laser Altimeter (GALA)
A laser altimeter with a 20m (66ft) spot size and 10cm (3.9in) vertical resolution at 200km (120mi) intended for studying topography of icy moons and tidal deformations of Ganymede.
Radar for Icy Moons Exploration (RIME)
The RIME antenna in stowed configuration. A "selfie" photograph, shortly after launch by the Juice monitoring camera 2 (JMC2), with Earth in the background
An ice-penetrating radar working at frequency of 9MHz (1 and 3MHz bandwidth) emitted by a 16m (52ft) antenna; will be used to study the subsurface structure of Jovian moons down to 9km (5.6mi) depth with vertical resolution up to 30m (98ft) in ice.
During post-launch commissioning of the spacecraft, the RIME antenna failed to properly deploy from its mounting bracket.[36] After several weeks of attempts to free the instrument, it was successfully deployed on 12 May of the same year.[37]
Juice-Magnetometer (J-MAG)
The scalar sub-instrument (MAGSCA), an optical magnetometer with low absolute error, is part of J-MAG
Juice will study the subsurface oceans of the icy moons and the interaction of Jovian magnetic field with the magnetic field of Ganymede using a sensitive magnetometer.
Particle Environment Package (PEP)
A suite of six sensors to study the magnetosphere of Jupiter and its interactions with the Jovian moons. PEP will measure positive and negative ions, electrons, exospheric neutral gas, thermal plasma and energetic neutral atoms present in all domains of the Jupiter system from 1 meV to 1 MeV energy.
Radio and Plasma Wave Investigation (RPWI)
RPWI will characterise the plasma environment and radio emissions around the spacecraft, it is composed of four experiments: GANDALF, MIME, FRODO and JENRAGE. RPWI will use four Langmuir probes, each one mounted at the end of its own dedicated boom and sensitive up to 1.6MHz, to characterize plasma, and receivers in the frequency range 80kHz to 45MHz to measure radio emissions.[38] This scientific instrument is somewhat notable for using Sonic the Hedgehog as part of its logo.[39][40]
Gravity and Geophysics of Jupiter and Galilean Moons (3GM)
3GM is a radio science package comprising a Ka transponder and an ultrastable oscillator.[41] 3GM will be used to study the gravity field – up to degree 10 – at Ganymede and the extent of internal oceans on the icy moons, and to investigate the structure of the neutral atmospheres and ionospheres of Jupiter (0.1 – 800 mbar) and its moons. 3GM carries Israeli-built atomic clock "that will measure tiny vacillations in a radio beam".[42][43]
Planetary Radio Interferometer and Doppler Experiment (PRIDE)
The experiment will generate specific signals transmitted by Juice's antenna and received by very-long-baseline interferometry to perform precision measurements of the gravity fields of Jupiter and its icy moons.
↑ Shapira, Aviv; Stern, Avinoam; Prazot, Shemi; Mann, Rony; Barash, Yefim; Detoma, Edoardo; Levy, Benny (2016). "An Ultra Stable Oscillator for the 3GM experiment of the JUICE mission". 2016 European Frequency and Time Forum (EFTF). pp.1–5. doi:10.1109/EFTF.2016.7477766. ISBN978-1-5090-0720-2. S2CID2489857.
Missions are ordered by launch date. Sign † indicates failure en route or before intended mission data returned. ‡ indicates use of the planet as a gravity assist en route to another destination.
Missions are ordered by launch date. † indicates failure en route or before any data returned. ‡ indicates use of the planet as a gravity assist en route to another destination.
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
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