Earth Explorer 7 Candidate Mission PREMIER: Addendum to the Report for Mission Selection

This report summarises the results of the activities performed in the context of the extension to the preparatory activities at Phase A level for the PREMIER mission, which have been completed since the publication of the PREMIER Report for Mission Selection (RfMS) (ESA SP-1324/3, May 2012). The findings are presented as an Addendum to the respective sections of the Report for Mission Selection and are numbered identically for allowing the reader to cross-reference the text to the relevant parts of the Report.

The activities performed for the PREMIER mission produced the following main results:
• Confirmation of the importance and urgency of the PREMIER science objectives as highlighted in newly published scientific studies;
• Detailed error analysis for the retrieval of IR extinction coefficient profiles in atmospheric windows, proving that cirrus and aerosols information will be derived with sufficient accuracy to meet the objectives of the mission;
• Definition of several independent procedures (in-flight calibration or retrieval) to increase the
determination accuracy of key instrument parameters, leading to improved error budgets of vertical profiles retrieval;
• Demonstration of the unprecedented horizontal and vertical resolution of the observation technique and of its capability to observe e.g. small scale filamentary trace gas structures with limited (500 m) vertical extent from the results of the ESSenCe campaign where the GLORIA airborne prototype of the PREMIER IRLS was flown;
• Demonstration of the capability to provide important constraints on the vertical distribution of Ozone in the troposphere and the stratosphere via simultaneous assimilation of limb and nadir Ozone data from concurrent satellite instruments;
• Technical consolidation of the STEAMR instrument design and subsequent optimization of the satellite configuration allowing to increase the clearance with the launcher fairing
• Consolidation of different elements of the IRLS design depending on the concept (mechanical/thermal architecture, front optics, cryostat, pointing mirror);
• Progress on technology pre-developments relevant to the IRLS instrument to demonstrate the maturity of key technologies (pointing mirror, front telescope, interferometer) prior to the start of the implementation phases;
• Start of the IRLS breadboard development to reduce the development risks and consolidate the instrument performance assessment.
• Consolidation of an option for the IRLS detectors based on the re-use of MTG detectors with the aim of reducing the development schedule and cost, subject to the acceptability of the reduced instrument performance;
• Execution of environmental test on selected STEAMR components/sub-assemblies to remove concerns about the space qualification.

The intent of this Addendum to the Report is to provide ESAC and the User Consultation Meeting
participants with an overview of the key findings from the Phase A extension in preparation of the User Consultation Meeting deliberations and the subsequent ESAC’s recommendation for the selection of the 7th Earth Explorer mission.