Thursday, April 13, 2023, at 2:15 p.m., Paris time, will launch from Kourou the space mission JUICE (Jupiter ICy moons Explorer), piloted by ESA.
With an expected arrival in 2031 after a very long journey, the probe will have an observation phase of 3 and a half years to study the entire Jovian system :
- Jupiter, located at 628 million kilometers from the Earth, the largest and most massive planet of the Solar System, gaseous, without surface ;
- and its three large icy moons : Ganymede, the largest moon of the Solar System, supposed to shelter under its icy surface a liquid ocean, and which has a magnetosphere, Callisto and Europa.
The objective of this large-scale ESA mission is to study the habitability of Jupiter’s icy moons, i.e. to determine if the conditions for the emergence of life can be met there, to obtain new data on the formation of the Solar System and planets, and to characterize Jupiter’s magnetosphere and its interaction with its moons.
Within the laboratories of Observatoire de Paris - PSL, our scientists are participating in this incredible exploratory adventure, which began, for some of them, 15 years ago.
Our researchers provided ephemeris to ESA for the probe trajectory. Under the CNES project management, they also contributed to three of the ten scientific instruments on board
▶ SWI (Sub-millimeter Wave Instrument)
A heterodyne radio telescope for studying the atmosphere
Within the Laboratory for the Study of Radiation and Matter in Astrophysics and Atmospheres (LERMA) of the Observatoire de Paris - PSL, the "Terahertz" instrumentation team has been developing, for decades, state-of-the-art radiometers to detect , with high frequency precision, extremely weak signals emitted by molecules present in planetary atmospheres, gas clouds in the interstellar medium or comets [1].
By developing electronic circuits on a sub-micron scale, based on semiconductor or superconductor technology, the group was selected to participate in the design and manufacture of the instrument’s microwave electronics. SWI. As such, it is the second instrumental French contribution to the JUICE mission.
The aim is to detect extremely weak signals emitted by moving molecules present in the high altitude winds of Jupiter, then in the ice of Ganymede and Europa.
The SWI instrument operates in the field of radio waves, in wavelengths less than a millimeter, at very high frequencies (1012 Hertz = Terahertz). It was designed to be able to perform instantly, or for a very short time, a spectrum of the signatures of water and methane molecules, with the very high spectral resolution of 107.
| (Re)Take the guided tour of the laboratory of the "Terahertz" team, filmed during the Fête de la science 2020 : |
There are currently no commercial sensors that can be used for this type of measurement. This is why the Observatoire de Paris - PSL is developing, in its laboratory, state-of-the-art technologies to produce this type of sensor, at 600 GHz and 1200 GHz, using nanotechnologies.
| [Scientific and industrial contributions to SWI : SWI was developed under the scientific responsibility of the Max Planck Institute (Germany), with the participation of the French laboratories :
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[Scientific and industrial contributions to SWI :
SWI was developed under the scientific responsibility of the Max Planck Institute (Germany), with the participation of the French laboratories :
- LERMA (Observatoire de Paris - PSL),
- C2N (Centre de Nanosciences et de Nanotechnologies) ;
- and the logistic support of CNES, the French space agency.
- LESIA (Observatoire de Paris - PSL)->https://lesia.obspm.fr/Mission-JUICE-Laplace-ESA.html], with a contribution to the definition of the scientific and data analysis objectives of the instrument.
The project also includes French industrial contributions :
- Syrlinks (company based in Rennes) for the synthesizer ;
- Société Audoise de Production - SAP, for the micromechanical blocks ;
- KERDRY (based in Brittany), for the gilding of the micromechanical blocks ;
- SERMA->https://www.serma-microelectronics.com/] (based in La Rochelle), for regulation circuits.
▪ The Laboratoire d’études spatiales et d’instrumentation en astrophysique (LESIA) of the Observatoire de Paris - PSL is the scientific co-lead (Co-PI ship) of the RPWI instrument consortium ;
LESIA has defined the specifications of the JENRAGE (Jovian Environment Radio Astronomy and Ganymede Exploration) experiment. This experiment is based on a combination of instruments : the RWI electric antenna, a radio receiver and an innovative onboard software. JENRAGE outperforms the instrumental capabilities of the Waves instrument on the Juno probe, currently orbiting Jupiter.
▪ For its part, the Plasma Physics Laboratory (LPP) of the École Polytechnique, under the secondary supervision of the Observatoire de Paris - PSL, is lead Co-I of the RPWI consortium, ensuring the scientific responsibility of the SCM (Search-Coil Magnetometer) induction magnetometer, which it has realized.
SCM will provide for the first time three-dimensional measurements of magnetic fluctuations in Jupiter’s magnetosphere. The performance of the expected measurements of the magnetometer is unprecedented, in particular thanks to the deployable mast of more than 10 m which accommodates it and will enable it to free itself from the disturbances of the satellite platform. These measurements will allow very innovative studies on the wave-particle interactions which are at the heart of fundamental processes, such as : magnetic reconnection, turbulence and particle acceleration, which are largely unexplored in Jovian plasmas today.
| [Scientific contributions to RPWI : RPWI was developed under the scientific responsibility of SNSB (Sweden), with the participation of the French laboratories :
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▶ MAJIS (Moons And Jupiter Imaging Spectrometer)
An infrared imaging spectrometer to characterize the surface of Jupiter’s moons
The MAJIS imaging spectrometer is one of the major instruments of the JUICE mission. Sensitive to wavelengths between 0.4 and 5.7 mm, with a spectral resolution of 3 to 7 nm, it allows to probe the chemical composition of atmospheres and the mineralogical and ice composition of lunar surfaces.
Its scientific objectives in the Jovian system are very broad, since they aim at characterizing the atmosphere of Jupiter from the depths (pressure of 5 bar) to the ionosphere (pressure of a few nano bar), at obtaining mineralogical maps of the Galilean icy satellites at high spatial resolution, and at characterizing the exosphere of these icy satellites.
The LESIA contributed technically to the MAJIS instrument at the level of the data processing pipeline. The expertise of the laboratory allows the development of algorithms whose goal is to provide to the scientific teams the geometrical parameters of observations in order to allow the later analysis of the data. The software will be provided to IAS and ESA to allow the calculation of geometric data cubes in real time.
| Scientific contributions to MAJIS : MAJIS was provided by IAS, a laboratory of CNRS and Université Paris-Saclay in Orsay (France) in the framework of a CNES/IAS technical partnership. It benefited from the expertise of LESIA in France, with the participation of IAPS (Italy) and ROB (Belgium). |
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(Re)See our 2023 greeting card, placed under the sign of JUICE :
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[1] Examples of realizations at LERMA, at the Observatoire de Pari - PSL, Terahertz radio frequency detection instruments : SAPHIR (on the Megha-Tropiques satellite for Earth observation), HIFI (on the Herschel space telescope), MIRO (on the Rosetta cometary probe) as well as on ALMA, large ground-based radio telescope.