Call for Expressions of Interest
to become a Member of the L4 Payload Working Group

9 December 2024

Today, the ESA Director of Science has issued a Call inviting science instrument experts, affiliated with institutions in the ESA Member States, to express their interest in becoming a member of the L4 Payload Working Group (L4PWG).

This Working Group will support ESA in elaborating, by mid-2026, the Strawman payload concept and technology roadmap on payload developments for 'L4', the first Large mission of Voyage 2050 covering the science theme "Moons of the Giant Planets". Please read carefully the Call for Expressions of Interest to become a member of the payload working group for the Large mission covering the science theme "Moons of the Giant Planets" document.

A Science Expert Committee (EC) for L4 was competitively appointed in 2022 to support the further definition of space mission concepts addressing the L4 science goals. The Expert Committee delivered their report in April 2024 and identified a mission to the Saturn system including a tour of several Saturn moons, the capability to sample Enceladus' plumes, and the delivery of a surface element on Enceladus for in-situ measurements as the most suitable to achieve the L4 mission scientific objectives.

In parallel, ESA has conducted a set of preliminary Concurrent Design Facility studies to investigate potential mission concepts, by taking into account the preliminary science priorities received from the Expert Committee, and has recently started industrial concept studies for raising awareness in industry, addressing high level trade-offs, and achieving a first technical and programmatic consolidation of the overall L4 mission concept.

The L4PWG will be tasked to:

• Analyse concepts and designs of instruments suitable for the achievement of the L4 mission objectives both for the orbiter and for the lander;

• Perform trade-off analyses of different instrument concepts and characteristics (including expected performance);

• Analyse technical maturity and areas of technology gaps and possible innovation to be implemented in the next five to ten years in Europe to achieve improved instrument performance and optimised resource utilisation;

• Support ESA in defining a technology roadmap targeted to miniaturisation of instruments (in particular for the lander payload complement) and resource optimisation;

• Support ESA in defining an L4 Strawman payload for the orbiter, including accommodation and operational constraints, and for the lander, including any sample acquisition and preparation and operational modes and timelines;

• Support ESA in defining the budget allocations for the Strawman payload (e.g., mass, power, data rates and volume) to be considered in future mission studies;

• Act as focus of interests to liaise with the broader technical and technology communities in Europe potentially interested to be engaged in the implementation of the L4 mission.

Expression of interest Submission form

Expressions of Interest in response to this Call must be submitted using the online form – see link to the form below or in the top navigation menu.

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Preliminary Schedule for this Call

Last updated: 26 March 2025

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