- 1Aurora Technology B.V. for ESAC, Camino Bajo del Castillo s/n, 28692, Villanueva de la Cañada
- 2Department of Mechanical and Space Engineering, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy
- 3Telespazio Germany GmbH for ESOC, Robert-Bosch-Str. 5, 64293 Darmstadt, Germany
The JUpiter ICy moons Explorer (JUICE), the European Space Agency’s first large-class mission under the Cosmic Vision 2015–2025 program, is dedicated to exploring the potential habitability of Jupiter’s icy moons: Europa, Callisto, and Ganymede. Launched on April 14, 2023, JUICE is currently in an 8-year cruise phase to Jupiter, utilizing gravity assists from Venus, Earth, and the Moon. Notably, JUICE is the first spacecraft to execute a Lunar-Earth gravity assist (LEGA), which was successfully completed in August 2024. This maneuver provided a critical trajectory adjustment while also allowing several onboard instruments to operate during the flyby.
Shortly after the Moon gravity assist, JUICE experienced an unforeseen acceleration attributed to an outgassing event. During the LEGA, radiometric observables, including Doppler and ranging data in the X-band, were collected by ESA’s New Norcia deep space station. These measurements were analyzed to characterize the outgassing-induced delta-V acting on JUICE. The analysis involved reconstructing the outgassing event and comparing it with models. The characterization of this event using radiometric data provides insights that complement measurements from other onboard instruments. For instance, the spacecraft’s reaction wheels recorded an excess torque as they compensated for the perturbation to maintain attitude control. The High-Accuracy Accelerometer (HAA), the Particle Environment Package (PEP), and the Submillimetre Wave Instrument (SWI) also captured data related to the outgassing event, enhancing its overall characterization.
In this work, we analyze radiometric measurements to provide a detailed quantification of the magnitude and orientation of the outgassing force during the flyby. These findings improve our understanding of non-gravitational forces affecting JUICE and contribute to refining our knowledge of the spacecraft's dynamical environment.
How to cite: Cappuccio, P., Sesta, A., Syndercombe, T., De Filippis, U., Durante, D., Di Benedetto, M., and Iess, L.: Estimation of Spacecraft Outgassing During the Lunar-Earth Gravity Assist of JUICE Using Radiometric Observations , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16492, https://doi.org/10.5194/egusphere-egu25-16492, 2025.
