European community-derived science and samples needs for future Lunar sample-return chains

Upcoming lunar missions are renewing opportunities to return samples from underrepresented terrains and sample states. Existing Apollo, Luna and Chang'e collections provide foundational science, but do not fully capture polar cold traps, farside and deep-crust contexts, pristine surface states, depth-resolved volatile stratigraphy, or transient properties requiring controlled return-chain conditions. For cold and volatile-rich materials, scientific value depends on retaining diagnostic properties such as volatile abundance and isotopic composition, phase state, stratigraphy, reactive surfaces, magnetic signatures, and contamination records from collection through analysis. The ESA-funded Lunar Cold and Transient Volatile-rich Return Sample Chain Needs activity addresses how science objectives, sample needs, and sample-integrity considerations can be linked to future European lunar return-chain planning.

This presentation will summarize preliminary results from the return-chain project, focusing on community input on science priorities and sample needs. We will discuss how broad lunar science drivers can be translated into target sample families, representative sampling modes, and diagnostic properties that must be retained. We will describe how these community-derived inputs are being used to identify knowledge gaps and to prepare prioritized return-chain requirements for later project work. The emphasis is on general lessons for future sample-return mission design rather than a single mission architecture.

The assessment combined a focused literature and sample-return heritage review with a structured online community survey and follow-up interviews with selected European experts. Survey and interview responses were coded to identify recurrent science questions, missing or underrepresented sample types, desired geological settings, contextual information, sample amounts, and analytical needs. Existing returned collections were mapped against sample type, provenance, context, sample state, contamination knowledge, and access constraints. The synthesis links science objectives to sample-package needs and to return-chain drivers including temperature, pressure and headspace, contamination, mechanical disturbance, magnetic exposure, and post-return handling.

Community input indicates that future sample return should be framed around targeted sample utility, not simply total returned mass. High-priority needs include cold-trap and permanently shadowed region volatile-rich materials; depth-registered volatile stratigraphy; topmost and shallow regolith preserving surface-bound species and dust state; palaeoregolith and stratified cores; young, old, and compositionally unusual volcanic materials; farside and primary crustal lithologies; South Pole-Aitken and impact-melt materials; mantle or lower-crust candidates; oriented magnetic samples; and biological or lunar-contact exposure samples. Cross-cutting return-chain drivers include retention of volatile, isotopic, mineralogical, magnetic, textural, and reactive-surface properties; preservation of geological context and stratigraphic order; and robust contamination knowledge supported by witness materials, blanks, contact-material records, and environmental logs. The survey also shows that several requirement thresholds remain only qualitatively defined, especially for mixed ice-regolith systems, transient thermal excursions, vibration and shock impacts on cores or fragile regolith, magnetic cleanliness, and acceptable contamination levels for volatile, organic, and surface-sensitive measurements. Presenting community-derived science and sample needs together with their return-chain implications, this work supports a more systematic European view of how future lunar sample-return elements can maximize science return while acknowledging technical feasibility, mission resources, and operational constraints.