TRIPLE – Ice Data Hub, Model-based Mission Support and Forefield Reconnaissance System

Abstract

The ocean worlds of our Solar System, like Saturn's moon Enceladus and Jupiter's moon Europa are covered with ice. Recently, these icy moons gained further scientific interest, as they are attributed some potential to sustain or host extraterrestrial life in a subglacial ocean. The investigation of these moons will also help to understand the evolution of the Solar System. The in-situ exploration of these moons requires novel technological solutions as well as intelligent data acquisition and interpretation tools. In 2020, the DLR Space Administration started the TRIPLE project (Technologies for Rapid Ice Penetration and subglacial Lake Exploration) which develops an integrated concept for a melting probe that launches an autonomous underwater vehicle (nanoAUV) into a scientifically interesting water reservoir and an AstroBioLab for in-situ analysis. These three components build up the TRIPLE system. As part of a second project stage, it is envisioned to build the TRIPLE system and test it in Antarctica in 2026. In this contribution, we are going to present the general concept of TRIPLE with a focus on the geophysically most relevant aspects. To navigate the melting probe through the ice, a forefield reconnaissance system (TRIPLE-FRS) based on combined radar and sonar techniques is designed. This will include radar antennas directly integrated into the melting head combined with a pulse amplifier and a piezoelectric acoustic transducer just behind the melting head. In addition, an in-situ permittivity sensor will be implemented to account for the ice structure dependent propagation speed of electromagnetic waves. With this system, obstacles as well as the ice-water interface at the bottom of the icy shell could be detected. To deliver key parameters such as transit time and overall energy requirement, a virtual test bed for strategic mission planning is currently under development. This consists of the Ice Data Hub that combines available data from Earth or any other planetary body – measured or taken from the literature – and allows display, interpretation and export of data, as well as trajectory models for the melting probe. We develop high-fidelity thermal contact models for the phase change as well as macroscopic trajectory models that consider the thermodynamic melting process and the convective loss of heat via the melt-water flow.