The Submillimetre Wave Instrument (SWI) is a spectrometer/radiometer instrument on board ESAs JUpiter Icy Moons Explorer (JUICE) that was successfully launched 14 April 2023. 

In the Swedish research community there is a broad interest in astrobiology, including questions of planetary system formation and habitability. The Swedish science goals for SWI therefore focus on obtaining better knowledge of the atmospheres (exospheres) of Jupiter's icy moons. Especially water, a main exosphere component in all three moons, may be the key to both atmosphere and moon formation: Its three-dimensional distribution will reveal how the atmospheres form and evolve, while the fraction of heavy water, the HDO/H2O, will pinpoint to what extent the moons consist of primitive materials and thus when and how they formed. Not only are these processes so far unsolved mysteries in our solar system, but the results will also be highly relevant in the context of exoplanets, of which a large fraction of the known ones are gas giants like Jupiter. Observations/detections of minor atmospheric species at the moons are also of particular interest from an astrobiology point of view, since the composition of sub-surface oceans is a crucial factor in determining their habitability: Can life exist elsewhere in the universe? 

In order to enable for researchers in Sweden to be actively involved in exciting new discoveries made possible by the SWI, and really benefit from its science return, we propose continued mandate and support for the Swedish Science co-I to maintain an active role in the SWI Science Consortium. Tasks during the cruise phase to Jupiter include preparations for interactive planning of observations and data handling that need to be ready when science data are expected from 2031. The wider Swedish community will also be informed and continuously updated about of the science possibilities of SWI.