The space science community has narrowed down the shortlist for ESA’s next ‘medium’ mission to three finalists: M-Matisse, Plasma Observatory and Theseus. Following further study, one will be selected for implementation as the newest addition to ESA’s space science mission fleet.
Medium (or ‘M-class’) missions are a key component of ESA’s Science Programme that enable Europe to answer important scientific questions. From the Sun to dark matter, ESA's existing M-class missions cover a huge range of space science topics. The newest addition would complement the fleet by shedding light on the habitability and evolution of Mars (M-Matisse), exploring the plasma environment around Earth (Plasma Observatory) or studying high-energy, short-lived events across the cosmos (Theseus).
The process of choosing a new mission is far from straightforward, and includes many steps. In December 2021, ESA called for proposals. From 27 responses, experts within and outside ESA used rigorous scientific and technical assessments and a peer review selection process to narrow down the number of proposals in the running. In November 2022, five mission concepts remained.
Between January and September 2023, these final five went through ‘Phase 0’ studies – an undertaking that explores the expected science that could be achieved with each mission, as well as coming up with a preliminary mission design.
Read more about the process and the final three missions here.
[Image description: An infographic-style visual with a black background and six circles following a timeline. The title is 'How are we selecting our next medium science mission?'. The red circles include the text as follows: November 2021 – Call for mission proposals; February 2022 – 27 first stage proposals; July 2022 – 10 second stage proposals; November 2022 – 5 proposals for pre-study; November 2023 – 3 proposals for further study; 1 M-CLASS MISSION. The first four circles are a faint red, the circle labelled 'November 2023' is brighter red, and the circle labelled '1 M-CLASS MISSION' is greyed out.]