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RIME: the radar sounder on JUICE

The Radar for Icy Moons Exploration (RIME) is one of the scientific instruments on the European Space Agency’s (ESA) Jupiter Icy Moons Explorer (JUICE) mission. RIME is a radar instrument designed to investigate the icy moons of Jupiter, particularly Ganymede and Europa, and to provide valuable insights into their subsurface structures and compositions. This is a summary of the RIME instrument and its objectives.

RIME (Radar for Icy Moon Exploration) is an ice penetrating radar that will characterise the structure of the Ganymede, Europa and Callisto subsurface, developed by @ASI_spazio @NASAJPL @Thales_Alenia_S @UniTrento @esascience


RIME’s primary goal is to study the subsurface properties of Ganymede and Europa, two of Jupiter’s largest moons. It aims to determine the thickness of the ice shells covering these moons and explore the presence of subsurface oceans, if they exist. RIME will investigate the distribution and properties of subsurface materials, including water ice and any potential liquid water layers beneath the ice.

Key Features

RIME is a radar sounder, which means it sends out radio waves that penetrate the moon’s surface and bounce back to the spacecraft. By analyzing the echoes or reflections of these radio waves, scientists can infer the composition and structure of the subsurface layers.

The instrument operates in the radio frequency range from 9 MHz to 26 MHz, allowing it to penetrate the icy surfaces of Ganymede and Europa.

RIME is designed to work in conjunction with the spacecraft’s high-gain antenna, using it to transmit and receive signals.

FIGURE 1 (left). Ray paths of the radar signals. In this figure, S is the pulse reflected from the ice surface, and B is the pulse reflected from the bottom of the ice (from Walker, Pearce, and Zanella, 1968).

Scientific Significance

By studying the subsurface of Ganymede and Europa, RIME can help answer fundamental questions about these moons, including the thickness of their ice shells, the presence of subsurface oceans, and the composition of their interiors.

Understanding the subsurface structures and properties of these moons is crucial for evaluating their potential habitability and the potential existence of life in subsurface oceans.

This is Figure 1 from Schroeder & Steinbrugge 2021. It demonstrates the bright basal reflection under the South Polar Layered Deposits on Mars based on a radargram from Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS). The bright basal reflection was originally interpreted by Orosei et al. 2018 as a subglacial lake.

Terrestrial Applications

Radar sounding technology has applications in precision agriculture. It can measure soil moisture content, assess soil compaction, and provide data for crop management.

Radar-based technologies can assist in locating missing persons or disaster survivors buried under debris or snow.

Radar sounders have been used to study glaciers and ice sheets on Earth. They help scientists measure ice thickness, map internal layering, and monitor changes in ice flow and structure, contributing to our understanding of climate change and sea-level rise.

Ground-penetrating radar (GPR) systems, which share some similarities with planetary radar sounders, are used for environmental applications. They help locate buried objects, assess soil and sediment layers, and detect underground utilities or archaeological artifacts.

Radar instruments have been employed for geological and geophysical investigations. They can help map subsurface rock formations, identify geological structures, and locate natural resources like minerals, oil, and groundwater.

Ground-penetrating radar is widely used in civil engineering for assessing the condition of infrastructure, such as roads, bridges, and buildings. It can identify voids, cracks, and subsurface anomalies that may indicate structural issues.

Radar technology is applied in mining for exploration and mapping of underground mineral deposits. It helps mining companies determine the size, depth, and characteristics of ore bodies.

Ground-penetrating radar has been used by archaeologists to non-invasively survey archaeological sites and locate buried artifacts, structures, and burial sites.

Can you think of a business solution in one of these areas?!

In summary, the RIME instrument on the JUICE spacecraft is a radar sounder designed to probe the subsurface of Jupiter’s icy moons, Ganymede and Europa. It aims to provide valuable insights into their internal structures and help answer key scientific questions about these intriguing worlds.

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