SWI « Submillimetre Wave Instrument »
The SWI instrument is the JUICE mission’s heterodyne radiotelescope. Its science goals are to study the atmosphere of Jupiter and the atmospheres and exospheres of its Galilean moons.
SWI is a radiotelescope comprising two subsystems:
- A Telescope Reception Unit (TRU) to point at target atmospheres
- An Electronic Unit (EU) containing the frequency boosters and RF radiometers that will receive and compare radio data from the TRU

The French contribution to SWI covers the MDF frequency distribution module supplied by the LERMA astrophysical and atmospheric radiation and matter research laboratory, and the hyper-frequency components of the local oscillator chain, the 1.2-THz submillimetre chain and the 300-GHz doubler of the 600-GHz chain.