Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 1: General overview
Abstract
The Jupiter Icy moons Explorer (Juice) was the first spacecraft ever that performed a combined gravity assist using both the Moon and Earth in succession. The double flyby required highly precise navigation to succeed. The LEGA allowed Juice to make a shortcut through the inner solar system on its way to Jupiter, using less fuel than would have been otherwise required. On 19 August 2024, Juice had its closest approach to the Moon. This first part of the manoeuvre accelerated the spacecraft by approximately 0.9 km s −1 relative to the Sun. On 20 August 2024, the spacecraft swung past Earth. This second part of the manoeuvre reduced the spacecraft's speed by 4.8 km s −1 relative to the Sun. This was a unique opportunity for its payloads to observe the Moon and Earth from a close distance as both calibration and science targets. The Submillimetre Wave Instrument (SWI), a dual channel heterodyne spectrometer observed both targets in two far-infrared bands around 500 and 250 µm wavelength in order to characterize and calibrate the overall performance of the instrument, including its receiver frontend, spectrometer backend and telescope mechanisms. In addition, the commanding pipeline and operations processes of the instrument were also tested close to its full range of flexibility using the relevant pipelines. In this paper we provide a contextual description of physical and functional characteristics of SWI, its operational principles and in-flight calibration activities during LEGA.
Related
- Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 3: Observations of the Earth as calibration target
- Juice-SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 2: Instrument operations
- JUICE-MAJIS Earth observations during the 2024 gravity assist: first analysis and comparison with PRISMA data
- Spectroscopic detection of terrestrial lightning from space by JUICE-MAJIS during Earth Gravity Assist
- Double Gravity-Assist Rendezvous Trajectory to Halley's Comet Using Deep-Space Low Thrust
BibTeX
@article{hartogh2026juiceswi,
title = {{Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 1: General overview}},
author = {Paul Hartogh and Ladislav Rezac and Thibault Cavalié and Christopher Jarchow and Raphael Moreno and Ali Schulz-Ravanbakhsh and Alberto Carrasco Gallardo and Borys Dabrowski and Samuel Goodyear and Miriam Rengel and Fabrice Herpin and Yasuko Kasai and Mikko Kotiranta and Emmanuel Lellouch and Axel Murk and Michael Olberg and Slawomira Szutowicz and Eva Wirström},
journal = {Annales Geophysicae},
year = {2026},
month = jul,
doi = {10.5194/angeo-44-645-2026},
url = {https://hal.science/hal-05761952v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 1: General overview
AU - Paul Hartogh
AU - Ladislav Rezac
AU - Thibault Cavalié
AU - Christopher Jarchow
AU - Raphael Moreno
AU - Ali Schulz-Ravanbakhsh
AU - Alberto Carrasco Gallardo
AU - Borys Dabrowski
AU - Samuel Goodyear
AU - Miriam Rengel
AU - Fabrice Herpin
AU - Yasuko Kasai
AU - Mikko Kotiranta
AU - Emmanuel Lellouch
AU - Axel Murk
AU - Michael Olberg
AU - Slawomira Szutowicz
AU - Eva Wirström
PY - 2026
DA - 2026/07/09
JO - Annales Geophysicae
DO - 10.5194/angeo-44-645-2026
UR - https://hal.science/hal-05761952v1
AB - The Jupiter Icy moons Explorer (Juice) was the first spacecraft ever that performed a combined gravity assist using both the Moon and Earth in succession. The double flyby required highly precise navigation to succeed. The LEGA allowed Juice to make a shortcut through the inner solar system on its way to Jupiter, using less fuel than would have been otherwise required. On 19 August 2024, Juice had its closest approach to the Moon. This first part of the manoeuvre accelerated the spacecraft by approximately 0.9 km s −1 relative to the Sun. On 20 August 2024, the spacecraft swung past Earth. This second part of the manoeuvre reduced the spacecraft's speed by 4.8 km s −1 relative to the Sun. This was a unique opportunity for its payloads to observe the Moon and Earth from a close distance as both calibration and science targets. The Submillimetre Wave Instrument (SWI), a dual channel heterodyne spectrometer observed both targets in two far-infrared bands around 500 and 250 µm wavelength in order to characterize and calibrate the overall performance of the instrument, including its receiver frontend, spectrometer backend and telescope mechanisms. In addition, the commanding pipeline and operations processes of the instrument were also tested close to its full range of flexibility using the relevant pipelines. In this paper we provide a contextual description of physical and functional characteristics of SWI, its operational principles and in-flight calibration activities during LEGA.
SN - 0992-7689
SN - 1432-0576
ER -