PROSPECT is a comprehensive payload package developed by the European Space Agency which will support the extraction and analysis of lunar surface and subsurface samples as well as the acquisition of data from additional environmental sensors. The key elements of PROSPECT are the ProSEED drill and the ProSPA analytical laboratory. ProSEED will support the acquisition of cryogenic samples from depths up to 1 m and deliver them to the ProSPA instrument. ProSPA will receive and seal samples in miniaturized ovens, heat them, physically and chemically process the released volatiles, and analyze the obtained constituents via mass spectrometry using two types of spectrometers. Contextual information will be provided by cameras which will generate multi-spectral images of the drill working area and of acquired samples, and via temperature sensors and a permittivity sensor that are integrated in the drill rod. The package is designed for minimizing volatile loss from the sample between acquisition and analysis. Initially developed for a flight on the Russian Luna-27 mission, the payload package design was adapted for a more generic lander accommodation and will be flown on a lunar polar lander mission developed within the NASA Commercial Lunar Payload Services (CLPS) program. PROSPECT targets science and exploration in lunar areas that might harbor deposits of volatiles, and also supports the demonstration of In-Situ Resource Utilization (ISRU) techniques in the lunar environment. PROSPECT operations are designed to be automated to a significant degree but rely on operator monitoring during critical phases. Here, we report the PROSPECT flight design that will be built, tested, and qualified according to European space technology engineering standards before delivery to the lander provider for spacecraft integration. The package is currently in the hardware manufacturing and integration phase with a target delivery to the NASA-selected CLPS lander provider in 2025.

The detection and characterization of lunar resources, including water ice, is a key area of interest for a new generation of lunar missions. The electrical properties of water ice in the extremely low frequency range support its detection by means of in-situ permittivity measurements. A new type of miniaturized subsurface permittivity sensor is presented, which is under development for the PROSPECT package on the Luna-27 lander mission. Here, the sensor concept is described, key design features are presented and possible operations modes are introduced. The expected accuracy for measurements of the relative permittivity along the borehole is similar to 10-15% and depends mainly on the accuracy of borehole geometry models. Laboratory test results from a prototype sensor on a water ice/simulant mixture at cryogenic temperatures are presented, demonstrating the capability to detect water ice at 125 K. The improved capabilities of the flight design are discussed, operational modes are explained and alternative electrode configurations for lunar landers and rovers are proposed.