CALL FOR A MEDIUM-SIZE AND A FAST MISSION OPPORTUNITY
IN ESA’S SCIENCE PROGRAMME

Date: 19 March 2025

The ESA Director of Science solicits the scientific community in ESA's Member States for proposals for both a Fast mission opportunity (to be launched around 2034 and with an estimated ESA Cost at Completion of 205M€ at 2025 economic conditions (e.c.)) and for a Medium-size mission opportunity (to be launched around 2041 and with an estimated ESA Cost at Completion of 670M€ at 2025 e.c.).

The  long-term  plan for the ESA Science Programme, Voyage 2050, was approved in June 2021, following a broad consultation of the scientific community and a peer review process, with final recommendations issued by an independent Senior Committee.

The plan includes three Large (L) missions in selected science themes (Moons of the Giant Planets, From Temperate Exoplanets to the Milky Way, and New Physical Probes of the Early Universe) and a set of Medium (M) and Fast (F) missions.

The selection of the F- and M-missions is based on a competitive, peer-reviewed process. Proposals in all fields of space science will be considered for both the F-class and M-class missions.

The proposal submission process for this Call will be based on a two-step approach.

​​​​​​​In parallel to the present invitation, the Director of Science has issued an Exploratory Call for a mini-Fast mission in ESA's Science Programme.

Call information package

The documentation for this Call includes a Letter of Invitation from the Director of Science, the Call for a Medium-size and a Fast mission opportunity in ESA's Science Programme document,  and an  Annex  to the Call document containing technical details. These documents are available to download from the right-hand menu. Please consult the documents for full details, requirements, and constraints for this Call.

Step-1 proposal details

As indicated above, responding to this Call is a two-step process. Step-1 proposals - for M-class and F-class mission proposals - must be submitted electronically (in pdf format), using the form linked below, by 12:00 (noon) CEST on 21 May 2025. Late submissions will not be considered.

Details of the required content for Step-1 proposals are given in the Call for a Medium-size and a Fast mission opportunity in ESA's Science Programme document.

Workshops in preparation for Step-2 proposals

M-class mission proposals

Proposers whose proposals passed the Step-1 selection will be invited to a dedicated workshop in preparation for Step-2 proposals. The purpose of the workshop will be to discuss in detail, collegially but also with individual sessions for each team, the feasibility of the proposed candidate M-class missions with the ESA engineering team, in advance of the submission of the Step-2 proposal. The date and location of the workshop will be communicated to the Lead Proposers.

F-class mission proposals

Two dedicated workshops, separated by a maturation phase of about two months, are planned for the F-class mission proposals that will have passed the Step-1 selection. The first workshop will be similar in format to the M-class mission workshop. Following the first workshop, the proposers will use the maturation phase to further consolidate their Step-1 proposals, including for the payload contribution scheme, and to possibly already address some weaknesses identified by ESA. The second workshop will close the maturation phase and will allow the proposers to receive final feedback from ESA before submitting the Step-2 proposals.

Step-2 proposal details

Step-2 proposals must be submitted electronically (in pdf format), using the appropriate form linked below. Please note the different deadlines for submission of M-class mission proposals and F-class mission proposals. Step-2 proposals not preceded by a corresponding Step-1 proposal will not be considered. Late submissions will not be considered.

Details of the required content for Step-2 proposals are given in the Call for a Medium-size and a Fast mission opportunity in ESA's Science Programme document.

Proposal endorsement by national funding agencies

Letters of endorsement from Member States must be provided for Step-2 proposals. Details of the context and requirements for the Letters are given in the Call for a Medium-size and a Fast mission opportunity in ESA's Science Programme document.

The Letters will have to be addressed to the ESA Director of Science and sent directly by Member States to the following email address by the indicated deadlines:

Schedule for this Call and important dates