The Cosmic Vision mission studies: status and overview of the M3 astrophysics candidates and L-class reformulation

Within the framework of the European Space Agency's Cosmic Vision 2015-2025 program, a third call for mission proposals (M3) was released to identify candidate missions for a launch slot in 2020-2022 that are to be studied in detail. The progress on the M3 astrophysics mission candidate studies is presented in this paper. The third medium-sized launch opportunity of the Cosmic Vision program limits the candidates to VEGA or Soyuz-compatible spacecraft to be launched from Kourou with a cost ceiling of 470 M∈. Following the first down-selection by the advisory structure, the selected proposals are undergoing internal studies in the Concurrent Design Facility. The mission concepts of the proposals are developed, the requirements refined, and the feasibility of the missions is assessed. The paper provides a summary of the status of these studies and describes the different spacecraft designs. A thorough description of the model payloads is given with special emphasis on their characteristics, requirements, design, and technical implementation. We also shed light on the ongoing reformulation of the IXO mission into ATHENA and present first results.