Jupiter Science Enabled by ESA's Jupiter Icy Moons Explorer

ESA’s Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 μm), and sub-millimetre sounding (near 530-625 GHz and 1067-1275 GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet

Jupiter science Enabled by ESA's Jupiter Icy Moons Explorer

ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 μm), and sub-millimetre sounding (near 530-625 GHz and 1067-1275 GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet

Moonraker: Enceladus Multiple Flyby Mission

Enceladus, an icy moon of Saturn, possesses an internal water ocean and jets expelling ocean material into space. Cassini investigations indicated that the subsurface ocean could be a habitable environment having a complex interaction with the rocky core. Further investigation of the composition of the plume formed by the jets is necessary to fully understand the ocean, its potential habitability, and what it tells us about Enceladus’s origin. Moonraker has been proposed as an ESA M-class mission designed to orbit Saturn and perform multiple flybys of Enceladus, focusing on traversals of the plume. The proposed Moonraker mission consists of an ESA-provided platform with strong heritage from JUICE and Mars Sample Return and carrying a suite of instruments dedicated to plume and surface analysis. The nominal Moonraker mission has a duration of ∼13.5 yr. It includes a 23-flyby segment with 189 days allocated for the science phase and can be expanded with additional segments if resources allow. The mission concept consists of investigating (i) the habitability conditions of present-day Enceladus and its internal ocean, (ii) the mechanisms at play for the communication between the internal ocean and the surface of the South Polar Terrain, and (iii) the formation conditions of the moon. Moonraker, thanks to state-of-the-art instruments representing a significant improvement over Cassini's payload, would quantify the abundance of key species in the plume, isotopic ratios, and the physical parameters of the plume and the surface. Such a mission would pave the way for a possible future landed mission

Moonraker -- Enceladus Multiple Flyby Mission

Enceladus, an icy moon of Saturn, possesses an internal water ocean and jets expelling ocean material into space. Cassini investigations indicated that the subsurface ocean could be a habitable environment having a complex interaction with the rocky core. Further investigation of the composition of the plume formed by the jets is necessary to fully understand the ocean, its potential habitability, and what it tells us about Enceladus' origin. Moonraker has been proposed as an ESA M-class mission designed to orbit Saturn and perform multiple flybys of Enceladus, focusing on traversals of the plume. The proposed Moonraker mission consists of an ESA-provided platform, with strong heritage from JUICE and Mars Sample Return, and carrying a suite of instruments dedicated to plume and surface analysis. The nominal Moonraker mission has a duration of 13.5 years. It includes a 23-flyby segment with 189 days allocated for the science phase, and can be expanded with additional segments if resources allow. The mission concept consists in investigating: i) the habitability conditions of present-day Enceladus and its internal ocean, ii) the mechanisms at play for the communication between the internal ocean and the surface of the South Polar Terrain, and iii) the formation conditions of the moon. Moonraker, thanks to state-of-the-art instruments representing a significant improvement over Cassini's payload, would quantify the abundance of key species in the plume, isotopic ratios, and physical parameters of the plume and the surface. Such a mission would pave the way for a possible future landed mission.Comment: Accepted for publication in The Planetary Science Journa

Moonraker: enceladus multiple flyby mission

Stars and planetary system

ELF whistler events with a reduced intensity observed by the DEMETER spacecraft

International audienceA survey of VLF frequency-time spectrograms obtained by the DEMETER spacecraft (2004-2010, altitude about 700 km) revealed that the intensity of fractional hop whistlers is sometimes significantly reduced at specific frequencies. These frequencies are typically above about 3.4 kHz (second cutoff frequency of the Earth-ionosphere waveguide), and they vary smoothly in time. The events were explained by the wave propagation in the Earth-ionosphere waveguide, and a resulting interference of the first few waveguide modes. We analyze the events whose frequency-time structure is rather similar, but at frequencies below 1 kHz. Altogether, 284 events are identified during the periods with active Burst mode, when high resolution data are measured by DEMETER. The vast majority of events (93%) occurs during the nighttime. All six electromagnetic field components are available, which allows us to perform a detailed wave analysis. An overview of the properties of these events is presented, and their possible origin is discussed

Ime-Hf Analyser for the Taranis Satellite

International audienceThe scientific instrument IME-HF is a high frequency analyzer for the future French satellite TARANIS which is intended to study radiation originating in transient luminous events connected with lightning discharges and occurring above thunderstorms. The satellite will be launched in 2013 on a polar orbit with an altitude of 700 km. The observation of electromagnetic radiation in HF range from space will provide us with important information about lightning properties, mainly in the case of intra-cloud discharges which are difficult to detect optically. We prepare a ground-based observational campaign with an identical high frequency analyzer. After the launch of the TARANIS satellite this campaign will complement the observations from space. The analyzed frequency band is from 100 kHz to 35 MHz. Selected interesting parts of the electric field waveform (sampled at 80 MHz) will be recorded. Signal from a filter bank will be also continuously stored and analyzed to trigger the waveform capture and to obtain a map of global distribution of intensity of HF waves. The analog part of the IME-HF instrument includes amplifiers, anti-aliasing filter and the set of twelve band-pass filters with amplifiers and RMS detectors. The core of the digital part of the electronics is the FPGA (Virtex4 family), where the sampled and digitized signal is processed. We present the first results of the tests of the IME-HF analyzer, including the analyzer response to several types of artificial signals and discharges

Ime-Hf Analyser for the Taranis Satellite

International audienceThe scientific instrument IME-HF is a high frequency analyzer for the future French satellite TARANIS which is intended to study radiation originating in transient luminous events connected with lightning discharges and occurring above thunderstorms. The satellite will be launched in 2013 on a polar orbit with an altitude of 700 km. The observation of electromagnetic radiation in HF range from space will provide us with important information about lightning properties, mainly in the case of intra-cloud discharges which are difficult to detect optically. We prepare a ground-based observational campaign with an identical high frequency analyzer. After the launch of the TARANIS satellite this campaign will complement the observations from space. The analyzed frequency band is from 100 kHz to 35 MHz. Selected interesting parts of the electric field waveform (sampled at 80 MHz) will be recorded. Signal from a filter bank will be also continuously stored and analyzed to trigger the waveform capture and to obtain a map of global distribution of intensity of HF waves. The analog part of the IME-HF instrument includes amplifiers, anti-aliasing filter and the set of twelve band-pass filters with amplifiers and RMS detectors. The core of the digital part of the electronics is the FPGA (Virtex4 family), where the sampled and digitized signal is processed. We present the first results of the tests of the IME-HF analyzer, including the analyzer response to several types of artificial signals and discharges

ELF whistler events with a reduced intensity observed by the DEMETER spacecraft

International audienceA survey of VLF frequency-time spectrograms obtained by the DEMETER spacecraft (2004-2010, altitude about 700 km) revealed that the intensity of fractional hop whistlers is sometimes significantly reduced at specific frequencies. These frequencies are typically above about 3.4 kHz (second cutoff frequency of the Earth-ionosphere waveguide), and they vary smoothly in time. The events were explained by the wave propagation in the Earth-ionosphere waveguide, and a resulting interference of the first few waveguide modes. We analyze the events whose frequency-time structure is rather similar, but at frequencies below 1 kHz. Altogether, 284 events are identified during the periods with active Burst mode, when high resolution data are measured by DEMETER. The vast majority of events (93%) occurs during the nighttime. All six electromagnetic field components are available, which allows us to perform a detailed wave analysis. An overview of the properties of these events is presented, and their possible origin is discussed

Anticorrelation between whistler occurrence and MLR and QP emissions

International audienceWe investigate a possible influence of lightning-generated whistlers on the occurrence of selected whistler mode emissions in the inner magnetosphere. Specifically, we focus on Magnetospheric Line Radiation (MLR) and Quasiperiodic (QP) emissions, i.e., electromagnetic waves at frequencies of a few kHz with a clear frequency/time modulation of the wave intensity. We use the data from the low altitude satellite DEMETER (2004-2010) to demonstrate that the occurrence of both these emissions exhibits a clear seasonal dependence, with a minimum during the northern summer. We argue that this dependence follows the global distribution of lighting-generated whistlers. Further, we use the whistler occurrence rate data obtained by the neural network on board DEMETER to directly compare whistler occurrence in the presence and in the absence of MLR/QP emissions. It is shown that the whistler occurrence rate as detected by the neural network is significantly lower in the presence of MLR/QP emissions than normally. We discuss whether this is due to a lower efficiency of whistler identification in the presence of MLR/QP emissions or whether this is a real effect suggesting a possible controlling role of whistlers for the occurrence of other electromagnetic emissions