This page provides information for the community of the study proposed to the European Space Agency (ESA) titled " Submillimeter Wave Instrument for EJSM. "

The "Europa/Jupiter System Mission" (EJSM) is an ESA/NASA/JAXA joint mission. It will study Jupiter and its magnetosphere, the diversity of the Galilean satellites, the physical characteristics, composition and geology of their surfaces, with a resolution and coverage far beyond what was achieved by Galileo. The baseline of the ESA contribution to this mission is the Jupiter Ganymede Orbiter (JGO).  The Submillimeter Wave Instrument (SWI) is an  instrument proposed in the JGO payload definition document, operational in the submillimeter-wave region, which will mainly investigate the middle atmosphere of Jupiter.

Abstract

The Submillimeter Wave Instrument (SWI) is part of the model payload on the Jupiter Ganymede Orbiter (JGO). JGO is ESA’s contribution to the Europa Jupiter System Mission (EJSM). SWI’s primary scientific objective is to investigate the middle atmosphere of Jupiter. SWI will contribute to the understanding of the circulation regime in the atmosphere as a function of latitude and altitude, how the vertically propagates to the upper layers to be radiated in space. In this sense SWI complements the Juno mission. Secondary objectives of SWI are related to the study of Galilean satellites. Io’s volcanic atmosphere will be studied through lines of SO2,  SO, NaCl, and perhaps other species. Water vapor will be observed in Europa’s atmosphere. Thermophysical properties of the Galilean satellite surfaces will be measured by radiometric observation of the surface. In the baseline configuration SWI will operate in two submillimeter wave bands around 600 GHz and 1200 GHz. Both receivers will be tunable within a bandwidth of approximately 20 % around the centre frequency. The antenna has a diameter of 30 cm and will be movable in at least one dimension. Two wideband high resolution spectrometers are foreseen. The observations geometry includes limb and nadir sounding. We have proposed to ESA to carry out a study, called "Submillimeter Wave Instrument for EJSM" that will meet the requirements of the instrument proposed in the JGO payload definition document. This study intends to find the optimal concept in terms of functional performance and requirements on JGO spacecraft resources, but will also investigate how the science and instrument design can be optimized for the Jupiter Europa Orbiter (JEO).