Status of the assessment phase of the ESA M3 mission candidate EChO

EChO is an M-class mission candidate within the science program Cosmic Vision 2015-2025 of the European Space Agency. It was selected in February 2011 to enter an assessment phase (phase 0/A). Following the internal Concurrent Design Facility study conducted by ESA in June/July 2011, a call for instrument studies was released in September, resulting in two consortia being selected to study the complete science instrument on board EChO throughout 2012. Similarly, two parallel competitive industrial studies of the complete mission will end early 2013. The instrument study focuses on the design and accommodation in the spacecraft of the scientific instrument, a spectrometer divided into several channels covering the 0.55 to 11 micron (0.4 to 16 micron goal) wave band. It also includes the design of the active cryogenic chain required to operate the instrument focal plane detectors. The industrial study focuses on the complete system-level design, including the mission analysis and operations, the spacecraft design (both service and payload modules) and also programmatic aspects such as risk mitigation, schedule and cost analyses. This paper describes the status of the EChO assessment study at the mid- term review (June/July 2012). It includes a short introduction to the EChO mission, a brief update on recent work by the Science Study Team (SST) to refine the science requirements, the description of the telescope trade-off and baseline selection, as well as the status of both instrument consortia and industrial system-level studies.