Analysis, Testing, and Design of a UHF and HF Peer-to-Peer Communication System for the Europan Cryosphere

Abstract

This study presents a validated design of a dual-band wireless relay system of “pucks” for through-ice communication between a cryobot and a surface lander during a future exploration of the Europan cryosphere. The design of a terrestrial demonstration system and the results of a 103 m through-ice system test in a relevant environment near Longyearbyen, Svalbard are presented. A radiative transfer model of the Europan cryosphere is applied to evaluate the anticipated performance of the notional Europan relay system. The proposed relay communication system utilizes a circularly polarized patch antenna with dielectric cover layer for use in an upper UHF band, and a crossed ferrite-loaded loop antenna for use in a lower HF band. A sub-surface radiative transfer model for Europa is used to extrapolate the performance of the terrestrial demonstration system in the cryogenic outer conductive and mushy inner convective cryosphere layers. The extrapolation considers the number of pucks and deployment strategy required to achieve reliable communication with the cryobot at the sub-surface ocean interface and the size, weight, and power (SWaP) requirements of those pucks. It is found that the link budgets of the puck pairs is attenuation dominated and highly affected by Europan ice salt fraction. The UHF/HF puck system is found to be suitable within the outer conductive cryosphere, but the SWaP of a UHF/HF puck system used to penetrate the inner convective cryosphere is high enough to warrant use of complementary communication methods.