Jupiter ICY moon explorer (JUICE): Advances in the design of the radar for Icy Moons (RIME)

Abstract

This paper presents the Radar for Icy Moon Exploration (RIME) that is a fundamental payload in the Jupiter Icy Moon Explorer (JUICE) mission of the European Space Agency (ESA). RIME is a radar sounder aimed to study the subsurface of Jupiter's icy moons Ganymede, Europa and Callisto. The paper illustrates the main goals of RIME, its architecture and parameters and some recent advances in its design

Radar attenuation in Europa's ice shell: Obstacles and opportunities for constraining the shell thickness and its thermal structure

“…For example, a radar sounding signal transmitted with peak power ∼140 dB above the background noise with ∼100 dB of geometric spreading losses, ∼35 dB of pulse compression gain, ∼20 dB of azimuth processing gain, and ∼10 dB of antenna gain would still have a signal‐to‐noise ratio of ∼5 dB after 100 dB of attenuation. While the exact numbers in the link budget will depend on the final instrument design, operational scenario, subsurface dielectric contrast, surface roughness, and signal‐to‐noise ratio detectability threshold, these values are in family with values found in the literature [e.g., Blankenship et al , ; Bruzzone et al , ; Di Paolo et al , ]. The volume scattering generated by structural heterogeneities especially in the upper parts of the ice shell is likely to be small at 60 MHz and negligible at 9 MHz [ Aglyamov et al , ] and is therefore neglected in the present study.…”

“…For the JUICE mission, the RIME instrument (Radar for Icy Moons Exploration) has been chosen to study the subsurface structure of the Galilean moons. It will operate in a single frequency band centred at 9 MHz with a bandwidth of 3 MHz [ Bruzzone et al , ]. NASA's spacecraft will carry the REASON instrument (Radar for Europa Assessment and Sounding: Ocean to Near‐surface), a dual frequency instrument with center frequencies of 9 MHz (bandwidth of 1 MHz) and 60 MHz (bandwidth of 10 MHz) [ Blankenship et al , ; Grima et al , ].…”

Assessing the detectability of Europa’s eutectic zone using radar sounding

“…Radar sounding is a powerful geophysical tool to detect and characterize features within an ice shell (McKinnon, 2005;Blankenship et al, 2009;Heggy et al, 2012;Bruzzone et al, 2015;Di Paolo et al, 2017;Kalousová et al, 2017). As electromagnetic pulses from a radar sounder travel through an ice shell, they reflect, scatter, and attenuate during propagation (Gudmandsen, 1971).…”

“…We compare the three eutectic geometry cases described below to this specular reflection in order to determine the effective reduction of Γ from the baseline scenario. This "effective reflectivity" can be combined with link budget (e.g., Bruzzone et al, 2015) and attenuation (e.g., Kalousová et al, 2017;Di Paolo et al, 2014) calculations to evaluate the detectability of each eutectic configuration. We do not model the attenuation in the ice shell above the eutectic zone.…”

“…The JUICE mission payload includes the Radar for Icy Moon Exploration (RIME) (Bruzzone et al, 2013) and the Europa Clipper mission includes the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) (Blankenship et al, 2009). RIME is planned to operate in a single frequency band centered at 9 MHz with a bandwidth of 3 MHz (Bruzzone et al, 2015) and REASON is planned to operate a dual frequency system with a High Frequency (HF) band centered at 9 MHz with a bandwidth of 1 MHz and a Very High Frequency (VHF) band centered at 60 MHz with a bandwidth of 10 MHz (Blankenship et al, 2009;.…”