Amateur Astronomer’s Support to ESA’s JUICE Mission

JUICE (JUpiter ICy moons Explorer) is the first large mission in the Cosmic Vision 2015-2025 programme. The spacecraft was launched on April 2023 and will arrive at the Jupiter system in July 2031. The primary science goals of JUICE are to characterize the Jovian icy satellites, studying their surfaces and interiors to unveil their history and internal structures, and to assess the emergence of habitable environments in their internal oceans [1]. Towards that end, JUICE will perform 3.3 years in orbit around Jupiter, followed by a later science phase in Ganymede’s orbit. During the Jupiter orbital tour, the spacecraft will run an extensive characterization of the Jupiter system, including the planet’s atmosphere [2], its magnetosphere and the ring system. JUICE will focus most of its observations of the Jovian planet during 62 close passes (perijoves), leaving wide periods of time in which the planet’s atmosphere will be observed less frequently, or at a poorer spatial resolution. A key period of time is the one to take place between orbit insertion on 21 July 2031 and the next perijoves on 7 Feb. 2032, 11 April 2032 and 10 May 2032, in which a larger data volume for Jupiter monitoring will be available, but with short times close to the planet. Several other epochs are of particular interest, including the inclined phase of the mission from October 2032 to July 2033, when coverage of the low latitudes is poorer; and after Ganymede’s orbit insertion, when JUICE will only observe Jupiter on limited occasions after November 2034.

JUICE’s investigation of Jupiter’s atmosphere [2] will combine observations made by multiple instruments at a range of spatial resolutions and over different time scales resolving many spatial and temporal scales in which different atmospheric processes develop. JUICE observations in the visible and near infrared with its JANUS camera will attain a spatial resolution of 10 km/pix in particular perijoves and spatial resolutions closer to 20 km/pix will be frequent [3]. MAJIS observations in the infrared will have a typical spatial resolution of nearly 100 km/pix in many perijoves [4]. Global mapping of the planet will be relatively rare, and JUICE’s investigation of Jupiter’s atmosphere will greatly benefit from ground-based support providing regular and frequent global imaging of the planet.

The recent Juno mission has demonstrated the strong science potential of combining frequent ground-based observations of Jupiter obtained by skilled amateur astronomers with detailed but less frequent observations acquired by spacecraft instruments. Here, we call to the amateur astronomy community to observe the planet supporting JUICE observations of the planet’s atmosphere. Current pro-am collaborations in the field of Jupiter studies make extensive use of data repositories such as ALPO Japan (https://alpo-j.sakura.ne.jp/indexE.htm) and PVOL (http://pvol2.ehu.eus/) [5]. We expect to support this activity through PVOL, where additional tools such as WinJupos (popular in the amateur community and available at https://jupos.org/) [6] and PlanetMapper (a versatile python software) [7] will be linked together with updated information about the dates and regions of interest to observe. Public data from JUICE will be released from its two monitoring cameras (JMC; Juice Monitoring Camera 1 and 2) and its navigation camera (NAVCAM). Data from the science instruments will have proprietary times and will be released through ESA’s Planetary Science Archive after proprietary time. We expect to regularly announce to the amateur community the main Jupiter areas that will be observed by the mission. Several scientists with a long tradition in establishing collaborations with the amateur community participate in different JUICE instrument teams. In addition, bringing together the efforts of a large space mission with amateur astronomers has a strong potential for mission outreach, and will ignite participation of the public in the scientific understanding of the solar system. Preliminary examples of potential JUICE and amateur astronomy synergies are already available in Europlanet Webinars with a first example being: Europlanet Juice Webinar 5: “Studying Jupiter with Juice-MAJIS & ground based pro-am instrumentation” (available online at  https://www.youtube.com/watch?v=NAIa87TgR_g). We expect that JUICE collaboration with amateur astronomers will broaden public involvement in the mission and will enhance outreach activities of the mission.

References

[1] Grasset et al. JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system. Planetary and Space Science, 78 (2013). [2] Fletcher et al. Jupiter Science Enabled by ESA's Jupiter Icy Moons Explorer. Space Science Reviews, 219 (2023). [3] Palumbo et al. The JANUS (Jovis Amorum ac Natorum Undique Scrutator) VIS-NIR Multi-Band Imager for the JUICE Mission. Space Science Reviews, 221 (2025). [4] Poulet et al. Moons and Jupiter Imaging Spectrometer (MAJIS) on Jupiter Icy Moons Explorer (JUICE). Space Science Reviews, 220 (2024). [5] Hueso et al. The Planetary Virtual Observatory and Laboratory (PVOL) and its integration into the Virtual European Solar and Planetary Access (VESPA). Planetary and Space Science, 150 (2018). [6] Jacquesson and Mettig. JUPOS: Amateur analysis of Jupiter images with specialized measurement software. European Planetary Science Congress (2008). [7] King and Fletcher, PlanetMapper: A Python package for visualising, navigating and mapping Solar System observations. Journal of Open Source Software, 8 (2023).