It is developing a map based on temperature data from NASAs Lunar Reconnaissance Orbiter.

The agency writes:

ESA is preparing a surface sampling payload that will prospect for lunar water among other resources. It is due to be flown to the Moon aboard Russias Luna-27 lander in 2025.

The payload is called Package for Resource Observation and in-Situ Prospecting for Exploration, Commercial exploitation and Transportation, or PROSPECT. A drill called ProSEED will extract samples, expected to contain water ice and other chemicals that can become trapped at the extremely low temperatures expected; typically -150 C beneath the surface to lower than -200 C in some areas.

Samples taken by the drill, says the ESA, will then be passed to the ProSPA chemical laboratory, being developed by an Open University team, for follow-up analysis of the chemical traces. This will test processes that could be applied for resource extraction in the future, it adds.

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ESA signals progress in hunting for water on the Moon - Electronics Weekly